Ph.Doctor Beauty Blog

Hyaluronic acid is on the label of almost every serum, moisturiser and sheet mask on the shelf — and for good reason. It is one of the few hydrating ingredients your skin already makes on its own. But its ubiquity has also bred a lot of half-truths: that it "plumps" wrinkles away, that more is always better, or that a single drop will transform dry skin overnight. The reality is more useful than the hype, and it hinges on two things most articles skip: what molecular weight actually means, and how you layer the product. This guide explains what hyaluronic acid is, how it hydrates skin, why the size of the molecule changes what it does, and — most importantly — how to use it so it works with your skin rather than against it. Key takeaways Hyaluronic acid is a humectant your skin produces naturally — its job is to bind and hold water. Molecular weight matters: high-molecular-weight HA sits on the surface and smooths; low-molecular-weight HA penetrates and hydrates deeper. In a controlled trial, topical HA improved skin hydration and elasticity, and low-molecular-weight HA also reduced wrinkle depth. Apply it to slightly damp skin and seal it with a moisturiser — otherwise, in dry air, it can pull water the wrong way. It suits virtually every skin type, including oily and sensitive, because it hydrates without adding oil. What is hyaluronic acid? Hyaluronic acid (HA), also called hyaluronan, is a glycosaminoglycan — a large sugar molecule — that occurs naturally throughout the body, with a substantial share found in the skin. It is a key molecule for skin moisture, with an unusual capacity to bind and retain water [1]. In the dermis it helps keep the tissue hydrated and cushioned; as we age, the skin’s own HA content and quality decline, which is one reason mature skin looks less plump and holds less moisture. In skincare, HA is used as a humectant: an ingredient that attracts water and holds it in the upper layers of the skin. That is the whole basis of its hydrating reputation. It does not "feed" the skin or rebuild collagen directly the way a retinoid does — its power is water management, and used correctly that is genuinely valuable. How hyaluronic acid hydrates the skin Applied topically, HA works by drawing water toward the skin surface and slowing its loss. A humectant like HA pulls moisture from two sources: from the deeper layers of the skin upward, and — when the surrounding air is humid enough — from the environment. Held in the outer skin, that water makes the surface look smoother, feel softer and appear more supple almost immediately. There is a catch worth understanding, because it explains most "HA made my skin worse" complaints. In a dry environment — winter heating, air conditioning, low humidity — there is little moisture in the air for HA to grab, so it can draw water from deeper in the skin and, without anything to lock it in, that water simply evaporates. The fix is not to avoid HA but to use it correctly: apply it to damp skin and seal it with a moisturiser. More on that below. Why molecular weight matters Not all hyaluronic acid behaves the same, and the reason is molecular weight — the size of the HA chain. This is the single most useful thing to understand about the ingredient, and it is why two products both listing "hyaluronic acid" can perform quite differently. High-molecular-weight (HMW) HA is a large molecule. Because of its size and water-holding capacity it forms a viscoelastic film on the skin surface that reinforces the barrier and reduces transepidermal water loss, giving an immediate smoothing, cushioned feel — but that same size largely prevents it from diffusing through the stratum corneum, so it stays on top [2]. Low-molecular-weight (LMW) HA is smaller, penetrates more readily, and delivers hydration to deeper layers over a longer period. Neither is "better" — they do different jobs, which is why many well-formulated products combine several molecular weights to hydrate at multiple levels at once. In a randomised controlled trial, topical 0.1% HA formulations across a range of molecular weights all significantly improved skin hydration and elasticity versus placebo, and the low-molecular-weight versions (50 and 130 kDa) additionally reduced wrinkle depth after 60 days — an effect the authors attributed to LMW HA’s better ability to penetrate [3]. What hyaluronic acid can — and cannot — do Set expectations correctly and HA rarely disappoints. It reliably improves surface hydration, makes skin look and feel smoother and more supple, softens the appearance of fine lines that are exaggerated by dryness, and supports a comfortable, less tight complexion. Because it is lightweight and oil-free, it does this without heaviness. What it does not do is permanently "fill" deep wrinkles the way an injectable dermal filler does — topical HA and injected HA are different applications entirely. Nor does it replace a moisturiser: HA attracts water, but it needs an occlusive or emollient layer to keep that water from escaping. Think of it as one specialised step, not a whole routine. Its best results come from consistent daily use as part of a sensible sequence. How to use hyaluronic acid correctly Almost every problem people have with HA comes down to application, not the ingredient. Two habits make the difference. Apply to damp skin. HA works best when there is water available to bind. After cleansing (or after a hydrating toner or essence), apply your HA serum while the skin is still slightly damp, not bone dry. This gives the humectant moisture to hold onto at the surface. Always seal it in. This is the step most people miss. Immediately after the HA has been applied, follow with a moisturiser to lock the water in place. Without that occlusive layer — especially in dry or heated air — the water HA is holding can evaporate and leave skin feeling tighter than before. The serum attracts the water; the cream keeps it there. Beyond those two rules: HA layers comfortably with most other actives, which is part of its appeal. It pairs well with vitamin C in the morning and can help buffer the dryness that stronger actives like retinoids can cause in the evening. As always, introduce one new product at a time so you can tell how your skin responds. How to choose by skin type One of HA’s biggest strengths is how broadly it suits different skin. Oily and blemish-prone skin. HA is ideal here precisely because it hydrates without oil. Oily skin still needs water, and a lightweight HA serum under a non-comedogenic moisturiser delivers hydration without a heavy, pore-clogging feel. Dry and mature skin. HA is a natural fit, but the sealing step is non-negotiable — pair it with a richer, barrier-supporting moisturiser to hold the water in. A blend of molecular weights, or an HA serum layered under a lipid-rich cream, tends to give the most comfortable result. Sensitive and reactive skin. HA is generally very well tolerated, since it mirrors a substance the skin already makes. Choose fragrance-free formulas and keep the routine simple. Skin under active treatment. During courses of retinoids, peels or in-clinic procedures, skin is often drier and more reactive; a simple HA serum sealed with a gentle moisturiser is a low-risk way to restore comfort. The Ph.Doctor approach to hydration Ph.Doctor is a dermocosmetics line developed by Dr. Nina Wiśniewska and biotechnologist Anna Sienkiewicz, built on a "less is more" philosophy: few ingredients, each with a defined function. For hydration, two products map neatly onto the two rules above — a serum that carries hyaluronic acid into the skin, and a lipid cream that seals it in. The serum is the Tetra C Serum, which pairs a stable vitamin C with a well-tolerated form of hyaluronic acid. Tetra C Serum SEE PRODUCT Tetra C Serum is, per its product card, "a synergy of 3 ingredients: Vitamin C + crocus extract + non-inflammable form of hyaluronic acid." The card describes that HA form — "Epidermosil is a combination of low-molecular hyaluronic acid and silanetriol" — which "nullifies the possible pro-inflammatory effects of hyaluronic acid," has "an effect on faster epidermal regeneration," and is "more effective in epidermal regeneration than hyaluronic acid alone." The serum overall "moisturizes, evens out skin tone, lightens hyperpigmentation and has an anti-aging effect," is "88% ingredients of natural origin," is vegan and "suitable for pregnant and breastfeeding women." Usage follows the damp-skin, then-moisturiser logic above: "apply 3 to 5 drops to the face and neck in the morning and evening. Once the product is absorbed, use a Ph.Doctor moisturizer." That moisturiser step is where the Lipid facial cream comes in — the occlusive, barrier-supporting layer that keeps the hydration from escaping. Lipid facial cream SEE PRODUCT Lipid facial cream is described on its card as "a universal cosmetic. Suitable for all skin types, including those sensitive or temporarily sensitized by dermatological therapies." It uses "niacinamide," which "strengthens the epidermal barrier," alongside "squalane and rice oil," so "the skin regenerates faster." Per the card’s tested results, it "reduced TEWL by 34% after 4 weeks of use" — TEWL being "the natural evaporation of water from the epidermis, which affects skin dryness" — which is exactly the water-loss that a humectant like HA needs sealed in. It is "89% natural ingredients," vegan, fragrance-free and "suitable for pregnant and breastfeeding women," and is listed as suitable "during dermatological treatments: retinoids, peels, laser." Used together the logic is simple and matches the science: the serum brings water-binding HA (plus antioxidant vitamin C) into slightly damp skin, and the lipid cream seals it in and reduces the water loss that would otherwise undo it. Frequently asked questions How often can I use hyaluronic acid? Daily, morning and evening, for most people. HA is gentle and mirrors a substance the skin already produces, so it does not require the cautious "start slow" build-up that stronger actives do. The key is not frequency but technique — apply it to damp skin and always seal it with a moisturiser. Should I apply hyaluronic acid to dry or damp skin? Damp. HA is a humectant, so it works best when there is water available to bind. Apply it after cleansing while the skin is still slightly moist, or after a hydrating toner or essence. On completely dry skin in a dry environment, HA has less surface water to hold and can feel less effective. What is the difference between low- and high-molecular-weight hyaluronic acid? It comes down to the size of the molecule. High-molecular-weight HA is large, stays on the surface, forms a smoothing film and reduces water loss. Low-molecular-weight HA is smaller, penetrates more readily and hydrates deeper layers over time. Neither is better — many products combine several weights to hydrate at multiple levels, and in trials low-molecular-weight HA has also been linked to reduced wrinkle depth. Can hyaluronic acid dry out my skin? It can if used incorrectly. In dry air, a humectant with no moisture to draw from can pull water from deeper in the skin, and without an occlusive layer that water evaporates, leaving skin tighter. This is entirely preventable: apply HA to damp skin and follow immediately with a moisturiser to lock the water in. Can I combine hyaluronic acid with retinol or vitamin C? Yes — HA pairs well with both. It sits comfortably alongside vitamin C in the morning and can help buffer the dryness that retinoids sometimes cause in the evening, which is one reason it is such a useful base layer. Introduce one new product at a time so you can judge how your skin reacts. Is hyaluronic acid suitable for oily or blemish-prone skin? Very much so. Oily skin still needs hydration, and HA provides it without adding oil or heaviness. A lightweight HA serum under a non-comedogenic moisturiser hydrates without contributing to clogged pores, which makes it one of the most universally suitable hydrating ingredients. Do I really need a moisturiser after hyaluronic acid? Yes, and it is the step that makes HA work. The serum attracts and holds water; the moisturiser seals it in and slows its evaporation. Skipping it — particularly in heated or air-conditioned rooms — is the most common reason people feel HA "did nothing" or even left skin drier. Hyaluronic acid in a serum or in a cream — which is better? They serve different roles. A serum delivers a higher concentration of HA in a lightweight base and is applied first, to damp skin. A cream generally provides the sealing, barrier-supporting layer on top. The most effective approach is usually to use both in sequence rather than to pick one. Selected references Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: a key molecule in skin aging. Dermatoendocrinol. 2012;4(3):253–258. Reviews HA as the key molecule in skin moisture, with a unique capacity for retaining water, and its decline with skin aging. Zanchetta C, Scandolera A, Reynaud R. Hyaluronic acid in topical applications: the various forms and biological effects of a hero molecule in the cosmetics industry. Biomolecules. 2025;15(12):1656. High-molecular-weight HA forms a viscoelastic surface film that reinforces the barrier and reduces transepidermal water loss but does not readily penetrate the stratum corneum; lower molecular weights penetrate more. Pavicic T, Gauglitz GG, Lersch P, Schwach-Abdellaoui K, Malle B, Korting HC, Farwick M. Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment. J Drugs Dermatol. 2011;10(9):990–1000. RCT: topical 0.1% HA of various molecular weights significantly improved skin hydration and elasticity; the 50 and 130 kDa (low-molecular-weight) groups significantly reduced wrinkle depth after 60 days.

Few skincare ingredients are as well studied — or as widely misunderstood — as retinoids. They are the closest thing skincare has to an all-rounder: the same vitamin A derivatives that smooth fine lines also support clearer, more even skin. But the word "retinoid" covers a whole family of molecules with very different strengths, and most of the frustration people have with them comes from picking the wrong one, or starting too fast. This guide explains what retinoids actually are, how they work in the skin, how the main forms differ in strength, and how to introduce one without the redness and peeling that make so many people give up in the first month. Key takeaways "Retinoid" is an umbrella term for all vitamin A derivatives — retinyl esters, retinol, retinaldehyde and retinoic acid among them. They work by converting to retinoic acid, which binds receptors in skin cells, stimulates collagen and supports renewal. The forms differ mainly in how many conversion steps they need: the fewer the steps, the more potent — and often the more irritating. Retinaldehyde sits in a useful middle ground: one step from retinoic acid, yet well tolerated in studies. Start low and slow, use it in the evening, and pair it with daily SPF — that is how you build tolerance and keep results. What are retinoids? "Retinoid" is a collective name for vitamin A (retinol) and its natural and synthetic derivatives [1]. They share a common ability: once in the skin they influence how skin cells behave — how quickly they renew, how much collagen the deeper layers produce, and how evenly pigment is distributed. That is why a single ingredient family is associated with so many different benefits, from smoother texture to a more even tone. The forms you will see on an ingredient list differ in potency, and that difference is the single most useful thing to understand before you buy. The main cosmetic forms, from gentlest to strongest, are retinyl esters (such as retinyl palmitate), retinol, and retinaldehyde (also called retinal). The prescription form, retinoic acid (tretinoin), is the active molecule the others ultimately become. How retinoids work in the skin Whatever form you apply, the skin has to convert it into retinoic acid — the only form that is biologically active. Retinoic acid binds to retinoic acid receptors inside skin cells and switches on a cascade of effects: it stimulates the growth of keratinocytes and fibroblasts and prompts fibroblasts to produce more extracellular matrix, including collagen [2]. Topical retinoids are recognised for promoting collagen synthesis and for inhibiting matrix metalloproteinases — the enzymes that break collagen down [1]. That combination matters for ageing skin in particular. Loss of firmness over time is driven partly by collagen breakdown; an ingredient that both encourages new collagen and slows its degradation works on the problem from two directions at once. This is why retinoids feature so consistently in evidence-based anti-ageing care. The retinoid family, from gentle to strong The reason the forms differ in strength comes down to conversion. Each form has to be metabolised through a chain of steps to reach retinoic acid, and every extra step costs potency. Retinyl esters → retinol → retinaldehyde → retinoic acid (three steps). The gentlest and least potent. Retinol → retinaldehyde → retinoic acid (two steps). The most common over-the-counter form. Retinaldehyde (retinal) → retinoic acid (one step). More potent than retinol, yet still cosmetic. Retinoic acid (tretinoin) — already active, prescription only. Because retinaldehyde is only a single conversion away from retinoic acid, it is more potent than retinol, while the prescription acid — being already active — tends to cause more irritation than the converted forms [1]. The practical takeaway: stronger is not automatically better. The best form is the most potent one your skin can use comfortably. For a deeper look at retinaldehyde specifically — and who it suits — see our dedicated article on retinal. Why retinaldehyde is a useful middle ground Retinaldehyde is worth singling out because it resolves the usual trade-off between strength and tolerability. In the skin it is metabolised to retinoic acid in a single step, so it delivers genuine retinoid activity. Yet in clinical work it has been notably well tolerated: in a study of topical retinaldehyde, the 0.05% and 0.1% preparations applied to facial skin were well tolerated and allowed prolonged use — up to three years — in patients with inflammatory skin conditions, while still producing a dose-dependent increase in epidermal thickness [3]. That is the appeal of a well-formulated retinaldehyde: meaningful results with a lower likelihood of the stinging and flaking that lead people to abandon stronger retinoids. What retinoids can — and cannot — do Realistic expectations are part of using retinoids well. With consistent use over months, retinoids are associated with smoother texture, softening of fine lines, more even tone and support for clearer, blemish-prone skin. What they are not is an overnight fix. The skin changes they drive — renewed cells, new collagen — take time to accumulate, and the first few weeks can actually look worse before they look better as skin adjusts. Patience and consistency matter more than strength. It is also worth knowing that retinoids and vitamin C are both useful but ask different things of a routine; how to combine them is a topic in its own right. How to start without irritating your skin The single biggest reason people fail with retinoids is starting too strong, too often. The adjustment period — sometimes called retinisation — is when skin gets used to the ingredient, and it is much smoother if you ease in. A sensible approach: choose a cosmetic strength appropriate to your experience, apply it only in the evening, start two to three times a week, and increase frequency only once your skin stays comfortable. Use a small amount — a pea-sized portion is enough for the whole face — and if redness, irritation or dryness appears, pause for a few days until it settles, then resume. Buffering with a moisturiser and keeping the rest of the routine simple both help. Two rules are non-negotiable. First, retinoids are evening ingredients. Second, daily sunscreen is essential while using them — both to protect the freshly renewed skin and to preserve the results you are working for. The Ph.Doctor approach to retinoids Ph.Doctor is a dermocosmetics line developed by Dr. Nina Wiśniewska and biotechnologist Anna Sienkiewicz, built on a "less is more" philosophy: few ingredients, each with a defined function. Its retinoid range is built around a stable form of retinaldehyde, encapsulated to release gradually — the middle-ground form described above — in two strengths for different needs and experience levels. For the face, the RetinALL IN ONE Face cream 0.1% is the stronger option. RetinALL IN ONE Face cream 0.1% SEE PRODUCT RetinALL IN ONE Face cream 0.1% is, per its product card, a cream "with a stable form of retinal 0.1%… encapsulated in cyclodextrin γ," a technology that "provides stability for 12 months after opening." It is described as a "balanced formula with minimal risk of irritation, thanks to the slow release system," is "anti-wrinkle, reduces hyperpigmentation, against imperfections, suitable for sensitive skin," and notes that "the action of retinal improves the appearance of acne-prone skin." Application follows the cautious pattern above: "apply a pea-sized portion… gently spread over the entire face (initially 2–3 times a week at night)," followed in the morning by "SPF 50 sunscreen"; if irritation appears, "take a break for a few days until symptoms subside," then build back up "until you develop full tolerance." For those who also want to treat the body — or prefer a lower strength — the FACE & BODY RetinALL 0.05% is the gentler option. FACE & BODY RetinALL 0.05% SEE PRODUCT FACE & BODY RetinALL 0.05% is a face-and-body cream with a stable form of retinal at 0.05%, also encapsulated in cyclodextrin with a slow-release system for "minimal risk of irritation." Per its card it is intended for all skin types, especially those with signs of skin ageing or a tendency to blemishes, is applied in the evening (the face starting 2–3 times a week, building to tolerance) and followed by SPF 50 in the morning. Note the indications: this product is contraindicated for pregnant women, though listed as suitable while breastfeeding per e-lactancia.org. As always, anyone pregnant, breastfeeding or under dermatological care should check with a professional first. Whichever you choose, the principle is the one running through this article: pick the form your skin can use comfortably, start slow, and protect the result with daily sun protection. Frequently asked questions What is the difference between retinol and retinal? Both are cosmetic vitamin A derivatives, but they differ in how close they are to the active form. Retinol needs two conversion steps to become retinoic acid, while retinaldehyde (retinal) needs only one. That makes retinal more potent than retinol at comparable concentrations, although it can also be felt sooner by reactive skin. Many people find a well-formulated retinal a good balance of results and comfort. When should I apply a retinoid? In the evening. Retinoids are used at night as part of your PM routine, on clean, dry skin. Daytime use is not recommended; instead, the focus during the day is sun protection. Applying at night and following with SPF in the morning is the standard, and it is exactly what Ph.Doctor's RetinALL instructions describe. Do I need to use SPF with a retinoid? Yes — daily, and it is not optional. Sunscreen protects the freshly renewed skin a retinoid produces and preserves the improvements you are working towards. A broad-spectrum SPF of at least 30 (the RetinALL cards specify SPF 50) used every morning is part of any retinoid routine, not an add-on. Why is my skin peeling and red after starting a retinoid? This is the adjustment period, sometimes called retinisation, and it is common in the first weeks. It usually means you are using too much, too often. Reduce frequency to two or three evenings a week, use only a pea-sized amount, buffer with a moisturiser, and pause for a few days if irritation flares — then resume and build up slowly. The reaction typically settles as the skin adapts. Can I use a retinoid if I have sensitive skin? Often yes, with the right form and pace. Gentler, well-tolerated forms such as a low-strength encapsulated retinaldehyde are designed to reduce irritation, and starting slowly makes a big difference. Patch-test first, begin once or twice a week, and keep the rest of your routine simple. If your skin is highly reactive or you have a skin condition, check with a professional before starting. How long until I see results from a retinoid? Plan in months, not days. The cell renewal and collagen support that retinoids drive take time to accumulate, and most people need consistent use over several weeks before changes in texture and tone become visible. The first few weeks can even look worse as skin adjusts. Consistency matters far more than chasing a stronger product. Can I use a retinoid with vitamin C or acids? You can, but not carelessly. Retinoids, vitamin C and exfoliating acids are all active ingredients, and stacking them in the same routine raises the risk of irritation, especially while you are still building tolerance. A common approach is to separate them — for example acids or vitamin C in the morning and a retinoid at night — and to introduce only one new active at a time. Are retinoids safe during pregnancy? Topical retinoid use in pregnancy is generally approached with caution, and individual products carry their own guidance. Ph.Doctor's FACE & BODY RetinALL 0.05%, for instance, is contraindicated for pregnant women per its product card. If you are pregnant or planning to be, do not start a retinoid without first checking with your doctor. Selected references Mukherjee S, Date A, Patravale V, Korting HC, Roeder A, Weindl G. Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clin Interv Aging. 2006;1(4):327–348. Reviews the retinoid family, receptor mechanism, collagen stimulation and MMP inhibition, and the metabolic conversion of the different forms to retinoic acid. Fisher GJ, Voorhees JJ. Molecular mechanisms of intrinsic skin aging and retinoid-induced repair and reversal. J Investig Dermatol Symp Proc. 1998;3(1):57–60. Retinoic acid stimulates growth of keratinocytes and fibroblasts and stimulates extracellular matrix (collagen) production by fibroblasts. Saurat JH, Didierjean L, Masgrau E, et al. Topical retinaldehyde on human skin: biologic effects and tolerance. J Invest Dermatol. 1994;103(6):770–774. Retinaldehyde produced a dose-dependent increase in epidermal thickness; 0.05% and 0.1% facial preparations were well tolerated and allowed prolonged use (up to 3 years).

Exfoliation is one of the easiest steps in skincare to overdo. Remove too little and dull, flaky skin lingers; remove too much, too often, and you weaken the very barrier you are trying to improve. Most of the confusion starts with the words themselves. "Chemical peel" and "enzymatic peel" are often presented as two opposites, when in reality an enzymatic peel is a specific, gentler branch of chemical exfoliation. Understanding what each one actually does at the level of the skin’s surface is what lets you choose the right one — and use it at a frequency your skin can tolerate. This guide explains how acid-based and enzyme-based peels work, what separates them in practice, and how to match a method to your skin type, from reactive and sensitive to oily and blemish-prone. Key takeaways An enzymatic peel is technically a type of chemical exfoliation — both dissolve the bonds between dead surface cells rather than scrubbing them off. Acid peels (AHA/BHA) loosen the "glue" between corneocytes; lactic acid is the gentlest, best-studied AHA for beginners and sensitive skin. Enzymatic peels use fruit proteases (papain, bromelain) that break down keratin only at the surface, with minimal irritation. Sensitive or reactive skin generally tolerates enzymes or low-strength AHA once a week; resilient skin can handle stronger AHA two to three times a week. Acids increase the skin’s sensitivity to UV — daily SPF 30–50 is non-negotiable while exfoliating. What exfoliation actually is The outermost layer of skin, the stratum corneum, is made of flattened dead cells called corneocytes, held together by protein "rivets" known as desmosomes. In healthy skin these connections are broken down enzymatically over time so that the oldest cells shed invisibly — a process called desquamation. When that natural shedding slows down, dead cells accumulate, and the skin can look dull, rough or flaky, with clogged pores. Exfoliation is simply a way of supporting or accelerating that shedding. There are two broad strategies. Mechanical exfoliation physically buffs cells away with grains or a tool. Chemical exfoliation, the focus of this article, dissolves the bonds that hold dead cells in place — either with acids or with enzymes. Because chemical methods work on the bonds rather than abrading the surface, they are generally more even and, when chosen correctly, gentler than scrubbing. Chemical peels: how acids work Acid exfoliants fall into two main families. Alpha hydroxy acids (AHAs) — such as lactic and glycolic acid — are water-soluble and work mainly on the surface. Beta hydroxy acid (BHA) — salicylic acid — is oil-soluble and can also work inside the pore, which makes it useful for oily and blemish-prone skin. The core mechanism of AHAs is a reduction in corneocyte cohesion: they loosen the bonds holding dead cells together in the lower part of the stratum corneum, which encourages those cells to release and the surface to renew [1]. Importantly, ultrastructural studies of glycolic acid show this is a "targeted" action on the desmosomes of the outermost, already-loosening layer (the stratum disjunctum), without disrupting the deeper barrier structures at the concentrations used in cosmetics [2]. In other words, a well-formulated acid peel works with the skin’s renewal process rather than stripping it. Why lactic acid is the gentle starting point Among the AHAs, lactic acid is the usual recommendation for beginners and for sensitive skin. It is a larger molecule than glycolic acid, so it penetrates more slowly and acts more gradually. It is also a humectant and a natural component of the skin’s own moisturising system, which means it draws and holds water as it exfoliates. There is a measurable barrier benefit too. In a controlled study, lactic acid increased the skin’s production of ceramides — the lipids that hold the barrier together — with the L-isomer raising stratum corneum ceramide levels by 48%, and this translated into improved barrier function and resistance to dryness [3]. That combination of exfoliation plus barrier support is why lactic acid is often the AHA of choice when skin is reactive or prone to dryness. Enzymatic peels: papain and bromelain Enzymatic peels take a different route to the same goal. Instead of acids, they use proteolytic (protein-digesting) enzymes derived from fruit — most commonly papain from papaya and bromelain from pineapple. These enzymes catalyse the breakdown of keratin proteins in the stratum corneum, releasing dead surface cells and supporting cell turnover, without the abrasion of a scrub [4]. The defining feature of enzymes is selectivity. They act on the proteins of the outermost dead-cell layer and are generally well tolerated, with minimal irritation across a broad pH range, which is why they are favoured in formulations for sensitive skin [4]. Bromelain in particular is valued for its soothing profile on redness-prone skin. Because enzymatic peels work only at the very surface, they typically produce no visible flaking and little to no downtime — at the cost of a milder, more gradual result than a stronger acid. Chemical vs enzymatic: a practical comparison It helps to think of these not as rivals but as points on a spectrum of intensity. The table below summarises the practical differences.   Acid peel (AHA/BHA) Enzymatic peel Active Lactic, glycolic (AHA); salicylic (BHA) Fruit proteases: papain, bromelain How it works Loosens bonds between dead cells; BHA also works in the pore Digests surface keratin proteins only Depth Surface to upper layers (concentration-dependent) Surface only Irritation potential Low to moderate (rises with strength) Low Best for Texture, dullness, blackheads, fine lines, uneven tone Sensitive, reactive, redness-prone skin; beginners Typical frequency 1×/week to start; up to 2–3× once tolerated Can be used more frequently; still 1–2×/week is sensible How to choose by skin type The right method depends less on trends and more on how reactive your skin is and what you want to address. Sensitive or reactive skin. Start with an enzymatic peel or a low-strength AHA (around 5% or below), no more than once a week. These options exfoliate while keeping the risk of stinging, redness and barrier disruption low. If you tolerate that well over several weeks, you can reassess. Normal to resilient skin. A stronger AHA — for example a 12% lactic acid formula — can be used once a week to begin with, building up to two or three times a week if your skin stays comfortable. This is the level at which you tend to see clearer improvements in texture, tone and the look of pores. Oily and blemish-prone skin. Salicylic acid (BHA) has the advantage of being oil-soluble, so it can work inside the pore where blackheads form. Lactic acid also has a role here, since it helps normalise surface shedding and unclog pores. For more on managing oilier skin day to day, see our guide on caring for oily skin. Skin with uneven tone or post-blemish marks. Regular, gentle AHA exfoliation can improve the look of discolouration over time by speeding surface renewal. This works best as part of a broader routine rather than as a quick fix. One universal rule: whichever method you choose, introduce only one new exfoliating active at a time, and avoid stacking it with other strong actives such as retinoids in the same routine until you know how your skin responds. After exfoliating: barrier and sun protection Exfoliating acids make freshly renewed skin temporarily more vulnerable to ultraviolet light. This is not a marketing caution — it is documented. Regulatory review of AHA cosmetics found that applying an AHA increased the skin’s sensitivity to UV-induced redness by 18% after four weeks of use, and that this heightened sensitivity can persist for up to a week after you stop [5]. A controlled study similarly showed that topical glycolic acid increased markers of UV damage in the skin, including erythema, DNA damage and sunburn-cell formation [6]. The practical conclusion is simple: daily broad-spectrum sunscreen of at least SPF 30 is part of any exfoliation routine, not an optional extra. Without it, you risk trading short-term smoothness for worsened pigmentation and premature ageing. For the full picture on photoprotection, see our dedicated guide. Beyond SPF, support recovery by keeping the rest of your routine gentle on peel days: a mild cleanser, a barrier-supporting moisturiser, and no second exfoliant. Always patch-test a new peel before applying it to the whole face. The Ph.Doctor approach to gentle exfoliation Ph.Doctor is a dermocosmetics line developed by Dr. Nina Wiśniewska and biotechnologist Anna Sienkiewicz, built on a "less is more" philosophy: few ingredients, each with a defined function. For exfoliation, two products map onto the steps above — careful preparation of the skin, and a single, well-tolerated acid peel. Good exfoliation starts with clean skin. The Osmogel Precleanser is the first cleansing step, removing make-up and UV filters before any further care; the lactic-acid peel is then applied to skin that has been thoroughly cleansed and dried. Osmogel Precleanser SEE PRODUCT Osmogel Precleanser is an "osmotic gel with micellar technology for eye and face make-up removal… Removes makeup and UV filters." It is "dedicated to all skin types, including sensitive skin," has a "formula consistent with the natural pH of the skin," and is "suitable during dermatological treatment." It is used as the first stage of cleansing, followed by the Gentle facial cleansing emulsion. For the peel itself, the Lactic acid 12% Face and body peeling is an AHA exfoliant formulated to stay tolerable. Lactic acid 12% Face and body peeling SEE PRODUCT Lactic acid 12% Face and body peeling is described as a peeling with 12% lactic acid that is "suitable for all skin types, including sensitive skin" and "gently removes dead skin cells, leaving the skin smooth and moisturized." The card notes that lactic acid "belongs to alpha-hydroxy acids (AHA)," is part of the skin’s "natural moisture factor," works as a "humectant" that "improves skin hydration," and that the product "stimulates the production of collagen, elastin and ceramides." It is a vegan formula (97% natural ingredients) and "suitable for pregnant and breastfeeding women." Usage follows the cautious approach described above. The card directs you to "apply a small amount… in the evening on cleansed and dried skin" and "wash off after 15 minutes," at a frequency of "1–2 times a week" for the face. It also instructs that while using the peel you should "use daily creams with UVA/UVB sunscreen min. SPF 30–50," and to perform an allergy test before first use. The peel should not be used on areas of acute inflammation or in case of known allergy to any component. If you are unsure where to begin, the principle is the same one that runs through this article: start gently, exfoliate no more than your skin comfortably tolerates, and protect the result with sunscreen. Frequently asked questions Which is better, an enzymatic or a chemical peel? Neither is universally better — they sit at different points on the same spectrum. Enzymatic peels are milder and act only at the surface, which suits sensitive, reactive or redness-prone skin and anyone new to exfoliation. Acid peels can deliver clearer results for texture, dullness and pores, but ask more of the skin. The best choice is the gentlest method that achieves what you want. How often should I exfoliate my face? For most people, starting once a week is sensible, increasing only if the skin stays comfortable. Sensitive skin should generally stay at one gentle session a week. More resilient skin can build up to two or three times a week with a stronger acid. Signs you are overdoing it include tightness, stinging, persistent redness and flaking — if these appear, reduce frequency. Is an enzymatic peel suitable for sensitive skin? Yes — it is often the preferred option. Fruit enzymes such as papain and bromelain act only on dead surface proteins and are generally well tolerated, with little irritation. Bromelain in particular has a soothing reputation on redness-prone skin. As with any new product, patch-test first and keep the rest of the routine simple. What concentration of lactic acid should I use at home? Home AHA peels commonly range from around 5% to 15%. Lower concentrations suit sensitive or beginner skin, while well-tolerated skin can use stronger formulas such as 12%. Whatever the strength, frequency matters as much as concentration: start once a week and adjust based on how your skin feels. Do I have to use SPF after a peel? Yes. Acids increase the skin’s sensitivity to UV, and that sensitivity can persist for several days after use. Daily broad-spectrum sunscreen of at least SPF 30 protects the freshly renewed skin and prevents the pigmentation and premature ageing that unprotected exposure can cause. Treat sunscreen as part of the exfoliation routine, not an afterthought. Can I do a chemical peel at home? Yes, within limits. At-home peels are formulated at lower strengths than professional treatments and are designed for short contact times. Follow the product’s instructions on amount, timing and frequency exactly, always patch-test first, and avoid using them on broken or inflamed skin. Stronger, deeper peels belong in a clinic. When should I avoid exfoliating? Skip peels on skin that is sunburnt, broken, actively inflamed or experiencing a flare. Avoid them if you have a known allergy to any ingredient in the product. Take particular care if you are already using other strong actives such as retinoids, and introduce only one new active at a time. If in doubt, especially during dermatological treatment, check with a professional first. Should I exfoliate before or after cleansing? After. Exfoliating acids and enzymes work best on clean, dry skin, so make-up, sunscreen and surface oils should be removed first. A two-step cleanse — a make-up-removing precleanser followed by a gentle cleanser — prepares the skin so the peel can work evenly. Selected references Van Scott EJ, Yu RJ. Alpha hydroxy acids: procedures for use in clinical practice. Cutis. 1989;43(3):222–228. AHAs reduce the thickness of hyperkeratotic stratum corneum by reducing corneocyte cohesion at lower levels of the stratum corneum. Fartasch M, Teal J, Menon GK. Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier. Arch Dermatol Res. 1997;289(7):404–409. Glycolic acid acts through a "targeted" desmosomal action in the stratum disjunctum without disrupting deeper barrier structures at the concentration used. Rawlings AV, Davies A, Carlomusto M, et al. Effect of lactic acid isomers on keratinocyte ceramide synthesis, stratum corneum lipid levels and stratum corneum barrier function. Arch Dermatol Res. 1996;288(7):383–390. L-lactic acid increased stratum corneum ceramides by 48% and improved barrier function. Trevisol TC, Henriques RO, Souza AJA, Furigo A Jr. An overview of the use of proteolytic enzymes as exfoliating agents. J Cosmet Dermatol. 2022;21(8):3300–3307. Proteolytic enzymes such as papain and bromelain mimic the skin’s desquamation process and are applied as exfoliants; pH, temperature and stabilisation are key formulation factors. U.S. Food & Drug Administration. Alpha Hydroxy Acids (Cosmetic Ingredients). AHA use increased UV sensitivity (skin reddening) by 18% after four weeks; effect can persist up to a week after stopping; SPF advised. Kornhauser A, Wei RR, Yamaguchi Y, et al. The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin. J Dermatol Sci. 2009;55(1):10–17. Topical glycolic acid increased UV-induced erythema, DNA damage and sunburn-cell formation; salicylic acid did not produce significant changes.

It is rarely genetics that decides how old your skin looks. It is usually the sun. A widely cited 2013 study by Flament and colleagues, which examined facial signs of aging in nearly 300 women, quantified the contribution of sun exposure to visible facial aging at approximately 80% on average [1]. Wrinkles, dark spots, loss of firmness, rough texture — most of it is the cumulative work of UV radiation, and most of it is preventable. That makes photoprotection — sometimes called sun protection — one of the best-supported steps in any skincare routine. This article is a practical, dermatology-led guide to what photoprotection actually is, how UV radiation damages your skin, and how to use SPF in a way that genuinely works. Every concrete claim is sourced to a peer-reviewed study or official body, listed at the end. Key takeaways About 80% of visible facial aging is caused by UV radiation — and is preventable. UVA (95% of UV reaching skin) ages — UVB (5%) burns. Both matter; both need broad-spectrum protection. SPF 30 blocks ~97% of UVB; SPF 50 blocks ~98%. The real-world difference favours SPF 50 because most people underapply. For full face protection, apply a 2-finger-length dose 15–30 minutes before sun exposure; reapply every 2 hours outdoors. Daily SPF is for every season — UVA passes through glass and snow reflects up to 80% of UV. Pair SPF with a vitamin C serum in the morning for the strongest combined defence. What photoprotection actually means Photoprotection is the umbrella term for everything we do to shield the skin from harmful effects of light, particularly ultraviolet (UV) radiation. The word itself is rooted in medical terminology — Greek phos (light) and Latin protectio (protection) — and it covers far more than just applying sunscreen. A useful way to think about it is as three overlapping layers of defence, each addressing what the others cannot. The first layer is behavioural: limiting time in direct sun during peak UV hours (roughly 10 a.m. to 4 p.m. in summer), seeking shade, and being aware of high-exposure environments like beaches, snow, and high altitudes. The second is physical: clothing that blocks UV, wide-brimmed hats, and sunglasses with UV-rated lenses to protect the delicate periorbital skin and the eyes themselves. The third is topical: dermocosmetics with UVA and UVB filters — what most people call sunscreen or SPF cream. It is worth understanding that no single layer is enough on its own. A high-SPF cream cannot fully compensate for two hours of midday sun on a glacier, and a hat alone will not prevent UVA from reaching the rest of your skin. The most effective photoprotection is the boring kind: small, consistent habits applied every day rather than dramatic interventions applied occasionally. Photoprotection is what you do every day, not only on holiday. How UV radiation damages skin Of the solar radiation that reaches the Earth's surface, ultraviolet light makes up only about 5% [2] — yet this small fraction is responsible for almost all the chronic damage we associate with the sun. UV is divided into three bands: UVC, which is almost entirely absorbed by the ozone layer and rarely reaches us; UVB, which causes sunburn and contributes to skin cancer; and UVA, which is largely responsible for long-term aging. Understanding the difference between UVA and UVB matters, because they damage the skin in completely different ways and require slightly different defences. UVA — the silent ager According to the World Health Organization, UVA makes up approximately 95% of the UV radiation that reaches the Earth's surface [3]. It is long-wave radiation, which means it penetrates deeply — past the epidermis, into the dermis, where collagen and elastin fibres sit. You do not feel UVA. It does not burn you. There is no immediate signal that anything is happening. But over the course of years, it degrades the structural proteins of the skin, drives the formation of pigmented spots, and quietly accumulates DNA damage that increases the long-term risk of skin cancer. Three properties of UVA make it particularly insidious. First, it is present all year round, with relatively small seasonal variation — winter does not switch it off. Second, it passes through window glass, which means it reaches you while you are driving, sitting at an office window, or working from home next to natural light. Third, because there is no visible warning, most people significantly underestimate their cumulative exposure. A good broad-spectrum sunscreen — clearly marked as protecting against UVA, ideally with a high PA rating or the European UVA-in-a-circle logo — addresses all three. UVB — the burner UVB accounts for about 5% of the UV that reaches us [4], but it has powerful, immediate effects on the skin. It is shorter-wavelength radiation, doesn't penetrate as deeply as UVA, and is the primary cause of sunburn — that red, hot, painful inflammation that appears a few hours after too much exposure. Tanning, often celebrated as a healthy glow, is actually the skin's defensive response to UVB damage: melanocytes produce more pigment to shield the deeper layers from further harm. UVB intensity varies sharply with season, time of day, latitude, and altitude. It is strongest in summer, around midday, closer to the equator, and at higher elevations — which is why an hour of skiing in the Alps can burn you as quickly as an hour on a Mediterranean beach. The SPF number on your sunscreen primarily measures protection against UVB, which is why a sunscreen labelled SPF 50 is not necessarily giving you equivalent UVA protection unless it is explicitly broad-spectrum. Photoaging — what is actually happening in your skin Photoaging is the dermatological term for the cumulative damage UV radiation causes to skin over time. It is distinct from chronological aging — the kind that happens naturally as you get older — and it is responsible for the majority of what most people think of as "aging skin." Dermatology research frames UV radiation as the dominant external driver of skin aging, alongside other "exposome" factors such as pollution, smoking and sleep quality [2]. The reason this distinction matters is that chronological aging is, for now, largely inevitable; photoaging is largely preventable. At a biological level, UV radiation triggers the formation of free radicals — unstable molecules with unpaired electrons that damage everything they touch: cell membranes, mitochondria, DNA strands, and the collagen and elastin proteins that give skin its structure. Your skin has its own antioxidant defences, but they are quickly overwhelmed by even moderate UV exposure. Free radical damage activates enzymes called matrix metalloproteinases (MMPs), which break down collagen faster than the skin can rebuild it [5]. Over years, the cumulative effect is a net loss of structural protein. The skin literally has less scaffolding holding it up. The visible signs of photoaging develop gradually and tend to appear together. Fine lines deepen into wrinkles, particularly around the eyes, forehead, and mouth. Pigmentation becomes uneven, with sun-induced spots called solar lentigines — sometimes informally referred to as age spots — appearing on the face, hands, neck, and chest. The skin loses elasticity and starts to feel thicker and rougher to the touch. Capillaries dilate and become visible, especially in those prone to rosacea. In more advanced cases, solar elastosis develops: a yellowish, leathery thickening of the skin caused by degraded elastin fibres clumping together, most often seen on the back of the neck and forearms in people with decades of outdoor exposure. The optimistic part of this picture is that prevention works extraordinarily well, and the strongest evidence for it comes from a randomized controlled trial conducted in Nambour, Australia. Hughes and colleagues followed 903 adults under 55 for 4.5 years, randomly assigned to either daily broad-spectrum sunscreen use or discretionary use. The daily-use group showed 24% less photoaging — measured by skin-surface microtopography — than the discretionary-use group [6]. Combine daily sunscreen with a topical antioxidant — a stable form of vitamin C is the most studied — and at night a retinoid, and you have one of the most consistently studied combinations of dermatology-recommended ingredients available. How to use SPF correctly — and why most people don't The uncomfortable truth about sunscreen is that the SPF number on the bottle is calculated under standardised laboratory conditions — using a specific dose of product applied evenly to a specific area of skin. In practice, almost nobody applies sunscreen the way the SPF test measures it. A 2014 review by Petersen and Wulf summarised the literature on real-world use: under natural conditions, people apply between 0.39 and 1.0 mg/cm² — roughly 20–50% of the standard test dose [7]. That means an SPF 50 cream, used at half-dose, may give you protection closer to SPF 15. The cream is doing what it promises; the application is not. The recommended dose for SPF testing, set by both the ISO standard 24444:2019 and the US FDA, is 2 mg/cm² of skin [8]. For an adult face and neck this works out to roughly 1.2 to 1.5 grams of product. The most useful visual references are the two-finger rule — a line of cream running the length of your index and middle fingers — or, equivalently, about a quarter of a teaspoon. If your sunscreen bottle is lasting you six months, you are almost certainly underdosing. Timing matters too. Apply sunscreen 15 to 30 minutes before sun exposure, not as you walk out the door. This is the same interval used in ISO SPF testing, and it gives the product time to form an even film on the skin [8]. Reapply every two hours during sustained outdoor activity, and immediately after swimming, heavy sweating, or towelling off — even with water-resistant formulas, friction removes a measurable amount of product. Equally important is what most people miss. The ears, the sides and back of the neck, the décolletage, the eyelids (using a formulation safe for that area), the backs of the hands, and the tops of the feet are some of the most common sites for chronic sun damage and pre-cancerous lesions, precisely because they are forgotten in daily application. A useful habit is to apply sunscreen in the same routine order every morning so nothing gets skipped. One small but important point on makeup with SPF. Foundation, powder, or BB cream containing SPF can be a useful additional layer, but it should never be your only source of protection. Most people apply a fraction of the foundation dose that would deliver the labelled SPF, and SPF values from different products do not add up — applying an SPF 30 foundation over an SPF 30 sunscreen does not give you SPF 60. You get whichever number is higher. Treat sunscreen as the protection layer and makeup as a bonus, not the other way around. Mineral and chemical sunscreens — what actually matters UV filters fall into two broad categories, and both have legitimate places in modern photoprotection. The choice between them is often presented as more dramatic than it actually is, but understanding the trade-offs helps you pick what works for your skin. Mineral filters — primarily zinc oxide and titanium dioxide — sit on the surface of the skin and work mainly by absorbing UV radiation, with a small amount reflected. They are generally well-tolerated, photostable, and start working immediately on application, which makes them particularly suitable for sensitive skin, reactive skin, rosacea, post-procedure care, infants and children, and pregnancy. The classic drawback is the white cast, especially with higher concentrations of zinc oxide, although modern micronised formulations have largely solved this on most skin tones. Chemical filters — including modern molecules like Tinosorb S, Tinosorb M, Uvinul A Plus, Mexoryl, and bemotrizinol — work by absorbing UV radiation and converting it into a small amount of heat. They allow for lighter, more elegant textures, layer beautifully under makeup, and the newer generation are remarkably photostable and well-studied for safety. The reputation that chemical sunscreens are "worse" than mineral ones is largely a legacy of older filters like oxybenzone, which has been progressively replaced in European formulations by far better alternatives. Many of the best modern sunscreens use hybrid formulations that combine mineral and chemical filters to get the benefits of both — broad protection, cosmetic elegance, and tolerance. If you have sensitive or reactive skin, a tendency to redness, or a diagnosed condition like rosacea or perioral dermatitis, mineral or hybrid formulas with a high proportion of zinc oxide are usually the safer starting point. If you have normal or oily skin and want something invisible under makeup, well-formulated chemical sunscreens are an excellent choice. Neither category is intrinsically dangerous, and choosing one over the other should be based on your skin's needs, not on marketing fear. Why daily SPF matters — yes, even in winter One of the most persistent myths in skincare is that sunscreen is a summer product. This belief survives mainly because of how dramatic sunburn is — visible, painful, immediate — and how invisible UVA damage feels in comparison. But the data is unambiguous: UVA is present at meaningful levels every single day of the year, including overcast winter mornings, and it is doing slow, cumulative damage whether you can feel it or not. Winter introduces some additional factors that make daily SPF arguably more important, not less. According to the World Health Organization, snow can reflect up to 80% of UV radiation, which is why a day on the slopes can burn your face as severely as a Mediterranean beach [3]. Dry beach sand reflects around 15%, sea foam about 25%. The cold itself weakens the skin barrier — that thin lipid-rich layer that keeps moisture in and irritants out — making it more vulnerable to oxidative damage. The contrast between freezing air outside and dry, heated air indoors compounds the effect. The result is skin that is simultaneously more exposed to UV and less able to defend itself against it. For anyone who spends time outdoors in winter — running, skiing, walking to work, even just walking the dog — a daily broad-spectrum SPF 50 is not overkill. It is the baseline. Pair it with a stable vitamin C serum in the morning and you have built a meaningful preventive shield against photoaging, no matter the season. Choosing the right SPF for your skin type The best sunscreen is the one you will actually use every day. Beyond that, matching the formulation to your skin type makes a meaningful difference to both comfort and outcomes. Sensitive, reactive, and rosacea-prone skin tolerates mineral or hybrid formulations best, particularly those with a high proportion of zinc oxide. Look for products free from fragrance, essential oils, and high concentrations of alcohol. Anti-redness ingredients like niacinamide or specific botanical complexes can be a useful bonus. This skin type benefits from a single, well-chosen daily SPF rather than rotating products. Oily and acne-prone skin needs lightweight, non-comedogenic textures — fluids, gels, and matt-finish creams. Avoid heavy occlusive ingredients that can trap sebum. Modern chemical or hybrid formulations tend to work well here. Be wary of the assumption that "all sunscreens cause breakouts" — usually the issue is texture or specific ingredients, not the act of applying sunscreen itself. Dry and mature skin can use richer SPF creams with added emollients and humectants. Look for formulations that combine UV protection with moisturising and barrier-supporting ingredients. Some people prefer to apply a separate moisturiser under their sunscreen; others find a single hybrid product more practical for daily use. Both approaches are valid. Skin prone to hyperpigmentation — whether from sun, hormones, or post-inflammatory marks after acne — benefits most from high SPF (50+), broad-spectrum coverage, and additional protection against visible light, which also contributes to pigmentation in darker skin tones. A vitamin C serum applied underneath provides additional antioxidant defence and helps fade existing pigmentation over time. Active and outdoor skin — for cycling, running, hiking, skiing, watersports — needs water-resistant formulations that hold up to sweat and friction. Apply generously before exposure and reapply every two hours, regardless of the resistance claim on the bottle. No sunscreen is truly waterproof. The Ph.Doctor approach to sun protection Ph.Doctor is a dermocosmetics line developed by Dr. Nina Wiśniewska and biotechnologist Anna Sienkiewicz. Our sun protection range includes two SPF 50+ creams designed for distinct use cases, both tested according to European standards: ISO 24444:2019/AMD 1:2022 for the SPF value and ISO 24443:2021 for UVA protection. A simple way to decide which one is for you: SUNSET AR — daily face cream for skin with a tendency to redness and visible vascularity. SUNSET SPORT — water- and sweat-resistant cream for active outdoor use and athletes. SUNSET AR Day Face Cream with SPF 50+ SEE PRODUCT SUNSET AR Day Face Cream with SPF 50+ is intended for all skin types, with a particular recommendation for people with vascular skin and a tendency to redness. It is designed for year-round use. The cream was tested for 28 days on people with sensitive skin prone to erythema, with measured reductions in redness and erythema area. Use daily in an amount corresponding to the length of two fingers; reapply every 2–3 hours during prolonged sun exposure. SUNSET SPORT SPF 50+ SEE PRODUCT SUNSET SPORT SPF 50+ is intended for all skin types, for year-round use including athletes and people active outdoors. In addition to the SPF and UVA standards above, the cream is tested for water resistance under ISO 2444:2019/A1:2022 and ISO 18861:2020 — with a separate water-resistance test performed after cycling. It was tested in application by 30 people actively practising sports. Apply at least one pump for the face (approximately 0.8–0.9 g per pump); reapply every 2–3 hours during prolonged sun exposure. If you use makeup, wait 10 minutes after applying the sunscreen. For both products, we recommend layering a stable vitamin C serum underneath. Our C Tetra Sérum uses vitamin C in the form of ascorbyl tetraisopalmitate — a stable, fat-soluble form of vitamin C that is well tolerated even by sensitive skin and does not require a low pH to be effective. According to the product specification, it acts as an antioxidant ideal for use under sunscreen, and increases the degree of UV protection. The product is vegan, contains 88% ingredients of natural origin and is suitable for pregnant and breastfeeding women. Apply 3 to 5 drops to the face and neck in the morning and evening; once absorbed, follow with a Ph.Doctor moisturiser. Frequently asked questions What is the difference between sunscreen and sunblock? In modern dermatology and regulatory terminology, the distinction has largely disappeared — no UV filter blocks 100% of radiation, even at high SPF, so "sunblock" is technically misleading. In most countries, including the EU, products are labelled simply as sunscreen or sun protection. Older language sometimes used "sunblock" for mineral filters and "sunscreen" for chemical, but this is no longer meaningful. What is the difference between SPF 30 and SPF 50? SPF 30 blocks about 97% of UVB radiation; SPF 50 blocks about 98% [9]. The difference sounds small, but it matters more than the numbers suggest — going from 3% transmitted UVB to 2% effectively halves the radiation that reaches your skin. Over years of daily use, that compounds. For daily preventive protection, SPF 50 is the dermatologically preferred choice. Do I need sunscreen if I work indoors? For most office settings, the UV exposure through windows is real but modest, and the main consideration is consistency. If you sit close to a window for hours at a time, or work from home in a sunlit room, daily SPF is worth the small effort. If your daily indoor exposure is genuinely minimal, the priority is wearing sunscreen reliably on the days you do go outside — including grey, overcast, and winter days. Does daily sunscreen cause vitamin D deficiency? Current evidence is mixed. A 2025 systematic review and meta-analysis pooling data from seven studies found that regular sunscreen use was associated with a small reduction in serum 25(OH)D levels — on the order of around 2 ng/mL — but the broader population-level effect is modest, and most authors conclude that incidental daily sun exposure remains sufficient for most healthy adults [10]. If you are at higher risk of deficiency — limited outdoor time, darker skin tones, northern latitudes, older age — supplementation is a safer and more controllable solution than deliberately skipping sunscreen. Can I use the same sunscreen for my face and body? Technically yes, but facial sunscreens are formulated for a much smaller surface area and tend to be more expensive per millilitre. Many also include anti-aging and skin-care active ingredients that are wasted on the body. A separate body sunscreen — simpler, larger volume, easier to apply generously — is usually the practical choice, especially for extended outdoor activity. Can I combine sunscreen with vitamin C? Yes, and you should. Vitamin C is one of the most well-studied antioxidants in skincare and provides a complementary layer of defence: sunscreen blocks most UV radiation, and vitamin C neutralises the free radicals from whatever gets through. The standard morning sequence is cleanse, vitamin C serum, moisturiser if needed, then sunscreen as the final step. How often do I really need to reapply? Every two hours of continuous sun exposure, immediately after swimming or heavy sweating, and after towel-drying. For a normal day at the office or at home, a single morning application is usually adequate. The two-hour rule applies most strictly to outdoor, daytime use during peak UV. Is mineral sunscreen always better for sensitive skin? Often, but not always. Zinc oxide and titanium dioxide are well-tolerated by most reactive skin types, which is why they are the default recommendation for rosacea, post-procedure care, and pregnancy. That said, modern chemical filters used in European formulations — particularly Tinosorb S, Tinosorb M, and bemotrizinol — are also well-tolerated by most users and may be more cosmetically elegant. The right choice depends on your specific reactivity pattern. If you would like to read about a closely related topic — uneven skin tone, pigmentation, and hyperpigmentation — see our article on pigmentation and skin discolouration, and what actually helps. Selected references Flament F, Bazin R, Laquieze S, Rubert V, Simonpietri E, Piot B. Effect of the sun on visible clinical signs of aging in Caucasian skin. Clin Cosmet Investig Dermatol. 2013;6:221–232. The study quantified the contribution of UV exposure to facial aging signs at 80.3% ± 4.82% (sun damage percentage, SDP) in a cohort of nearly 300 Caucasian women. Krutmann J, Bouloc A, Sore G, Bernard BA, Passeron T. The skin aging exposome. J Dermatol Sci. 2017;85(3):152–161. Foundational review establishing the "skin exposome" framework — UV radiation, pollution, smoking, nutrition, stress and lack of sleep as the primary external drivers of skin aging. World Health Organization. Ultraviolet (UV) radiation — Q&A. WHO confirms that long-wavelength UVA accounts for approximately 95% of UV radiation reaching the Earth's surface, that snow can reflect as much as 80% of UV radiation, and that UV is a small fraction of total solar irradiance. International Agency for Research on Cancer (IARC). Solar and Ultraviolet Radiation — IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Reference data on UVB representing about 5% of solar UV reaching Earth's surface; reviews altitude, latitude, and cloud effects on UVB intensity. Singh A, Yadav S, Mehta D, et al. A comprehensive review of the role of UV radiation in photoaging processes between different types of skin. 2025. Reviews the role of matrix metalloproteinases (MMPs) in UV-induced collagen degradation and the differential photoaging mechanisms across Fitzpatrick skin types. Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med. 2013;158(11):781–790. The landmark Nambour randomized controlled trial in 903 Australian adults, showing 24% less photoaging (measured by skin-surface microtopography) in the daily-sunscreen group versus discretionary use over 4.5 years of follow-up. Petersen B, Wulf HC. Application of sunscreen — theory and reality. Photodermatol Photoimmunol Photomed. 2014;30(2-3):96–101. Literature review documenting that real-world sunscreen application typically delivers only 0.39–1.0 mg/cm² versus the 2 mg/cm² test dose, substantially reducing the protection factor delivered in practice. International Organization for Standardization. ISO 24444:2019 — Cosmetics — Sun protection test methods — In vivo determination of the sun protection factor (SPF). Specifies the standard test dose of 2.0 mg/cm² ± 0.05 and the 15–30 minute interval between application and UV exposure. Northwestern Medicine. What do the SPF numbers mean? Confirms that SPF 30 blocks approximately 97% and SPF 50 blocks approximately 98% of UVB radiation. Consistent with FDA and dermatology consensus. Gatta E, Cappelli C. Sunscreen and 25-Hydroxyvitamin D levels: friends or foes? A systematic review and meta-analysis. Endocr Pract. 2025. Meta-analysis of seven prospective studies in 1,495 adults reporting a standardized mean difference of approximately –2 ng/mL in serum 25(OH)D associated with sunscreen use, with significant heterogeneity in clinical impact.

If you are currently undergoing dermatological treatment for acne, whether with antibiotics or retinoids, you can safely use most Ph.Doctor products. The only exception is Ph.Doctor Tetra C Serum, which should not be used during treatment if your doctor has prescribed isotretinoin, tetracycline, adapalene, benzoyl peroxide, a combination of tretinoin and an antibiotic, or topical antibiotics. It is best to introduce this product only after the active phase of treatment has ended and remission has been achieved. During treatment, you can use a combination of Gentle Facial Cleansing Emulsion, Glutathione Eyelid Serum, Lipid Facial Cream, and Creamy Body Lotion. These products work very well alongside topical tretinoin treatment. Once your treatment has ended and you move on to maintenance skincare, you can fully incorporate these and other products into your routine. However, do not stop your dermatological treatment prematurely, as the effects of retinoids may take approximately 12 weeks of regular use to become noticeable. Patience is essential. Remember to protect your skin from the sun every day and use SPF 30–50 throughout the year. During oral isotretinoin treatment, you can safely rely on intensive hydration from Ph.Doctor. Lipid Facial Cream, Creamy Body Lotion, and Vitamin C Hand Cream are suitable for sensitive skin and can be used during this time. We recommend introducing the brand’s other products only after completing your treatment to minimise the risk of irritation. During this phase, avoid using the Ph.Doctor body scrub, Lifting Elbow and Knee Cream with Glycolic Acid, and 12% Lactic Acid Peel. While taking isotretinoin, focus primarily on intensive skin hydration and avoid anything that may cause irritation. If you are currently using retinoids, such as retinal, we recommend applying the 12% Lactic Acid Peel only once a week in the evening, leaving it on for 10 minutes, and using it instead of retinal on that particular evening.

Jak alkohol ovlivňuje kondici pleti? Dehydruje, zvyšuje citlivost pleti a urychluje tvorbu vrásek. Zjistěte, jak tomu předejít správnou hydratací, péčí a nahrazením alkoholu šetrnějšími nápoji.

Jak začít s péčí o pleť? Klíčem je obnova lipidové bariéry, dvojí čištění a správná aplikace produktů. Podívejte se na doporučenou rutinu a postupy, které posílí a zklidní vaši pleť.

Pokud je vaše pleť poškrábaná, zašedlá a plná pigmentových skvrn, pravděpodobně máte jizvy po akné. První krok: přestaňte se škrábat, mačkat pupínky a používat hrubé peelingy.Tím jen zhoršujete zánět a podporujete vznik pigmentových skvrn. Regenerace pleti s Tetra C Sérum Ph.Doctor Vyzkoušejte Tetra C Sérum Ph.Doctor, které obsahuje 3 % tetraizopalmitátu askorbylu, stabilní a účinnou formu vitaminu C. Díky emulzní textuře poskytuje vysokou biologickou dostupnost aktivních látek z lipofilní i hydrofilní fáze. Sérum je obohacené o hydratační látky: kyselinu hyaluronovou, silanetriol, alantoin a D-panthenol, který poskytuje tak komplexní péči bez ucpávání pórů. Dále obsahuje výživné emolienty jako makadamový a rýžový olej, vitamín E a skvalan.Pokročilá složka Dermcom (2%) stimuluje tvorbu kolagenu a elastinu. Laboratorní testy prokázaly nárůst kolagenu o 115 % po 2 týdnech, takže pleť je pevnější a pružnější. Jak používat produkty Ph.Doctor Čištění: Jemná čisticí emulze Ph.Doctor (pH 4,5–6) Ráno: Tetra C Serum Ph.Doctor + Lipidový krém Ph.Doctor Večer: FACE & BODY RetinALL (retinal 0,05 %) nebo RetinALL IN ONE (retinal 0,1 %) Po 15 minutách můžete nanést Lipidový krém Ph.Doctor. Kombinace retinoidů a vitaminu C Ano, Tetra C Sérum můžete bezpečně kombinovat s retinalem.Pokud používáte retinoidy na předpis, poraďte se s dermatologem. Nezapomínejte na SPF! Každodenní ochrana SPF 50 je klíčem ke zdravé pleti po celý rok. Doplňková péče Krémový tělový balzám Ph.Doctor – naneste do 5 minut po koupeli. Peeling s 12% kyselinou mléčnou Ph.Doctor – vyhlazuje, rozjasňuje a stimuluje tvorbu kolagenu. Používejte střídavě s retinalovými krémy po dosažení tolerance pokožky.

Trápí vás celulitida? Naučte se rozpoznat vodní a tukovou celulitidu a zjistěte, jak na ni účinně. Správná péče, kartáčování těla, studené oplachování i speciální kosmetika Ph.Doctor vám pomohou vyhladit pokožku a zbavit se pomerančové kůže.

Trápí vás alergie na kosmetiku? Zjistěte, jak správně provést alergický test doma. Jednoduchý postup vám pomůže odhalit možnou reakci ještě před plným použitím produktu a ochránit vaši pleť před nežádoucími projevy.

Trápí vás mastná pleť? Objevte, jak ji šetrně čistit, hydratovat a regulovat tvorbu mazu. Ph.Doctor nabízí účinnou péči, která zmatní pleť, zjemní póry a pomůže předcházet nedokonalostem.

Chcete zpomalit stárnutí pleti? Retinal podporuje kolagen, vyhlazuje vrásky a pomáhá sjednotit tón pokožky. Zároveň redukuje akné i pigmentace a zlepšuje texturu pleti.