Clinical Reference
The Science of Skin
Why one serum works and another sits on the surface: the biology, the actives, and the formulation rules that decide.
01 · Method
Evidence, Not Marketing
Clinical skincare is separated from cosmetic skincare by a single measure: evidence. Every active in SK1N's catalog has been studied in peer-reviewed dermatological literature, and every formula is built to the concentration and pH proven to deliver a measurable biological effect on living skin.
This is biochemistry applied to physiology. Retinoids accelerate keratinocyte turnover. Antioxidants quench free radicals before they damage cellular DNA. Acids dissolve the bonds holding dead cells to the surface so actives can reach the layers that matter. The right molecule, at the right strength, at the right pH. Nothing else.
02 · Biology
Where Actives Have to Go
Skin is a layered barrier. An active only works if it reaches the layer where its target lives. Understanding these three layers explains why concentration, pH, and delivery matter more than brand.
0.01–0.04 mm
Stratum Corneum
The outermost barrier: flattened corneocytes embedded in a lipid matrix of ceramides, cholesterol, and fatty acids. Its slightly acidic pH (4.7–5.5) and lipid seal keep water in and irritants out.
0.05–1.5 mm
Epidermis
Living keratinocytes migrate upward over ~28 days, shedding as the stratum corneum. Melanocytes here produce melanin; this is where pigmentation begins and where most actives must reach.
1–4 mm
Dermis
The structural layer. Collagen and elastin fibres give skin its firmness and recoil; fibroblasts synthesise them. Blood supply and nerve endings live here. This is the target for anti-ageing actives.
03 · Actives
Key Active Ingredients
Eight actives form the backbone of evidence-based skincare. Each is included at a clinically validated strength and delivered to its target layer.
Cell Turnover
Retinoids
Bind retinoic acid receptors to accelerate keratinocyte turnover and stimulate fibroblast collagen synthesis. Reduces fine-line depth over 12+ weeks of nightly use. Start low; build tolerance.
Antioxidant
L-Ascorbic Acid
The bioactive vitamin C. Neutralises free radicals, inhibits tyrosinase to brighten pigmentation, and is essential to collagen cross-linking. Effective at 10–20% and pH below 3.5.
Hydration
Hyaluronic Acid
A glycosaminoglycan that binds up to 1,000× its weight in water. Low-molecular weights penetrate the epidermis; high-molecular weights sit on the surface for an immediate smoothing film.
Cellular Signalling
Peptides
Short amino-acid chains that act as messengers, signalling fibroblasts to produce collagen (e.g. Matrixyl) or relaxing expression muscle tone (e.g. Argireline). Firmness without irritation.
Barrier Repair
Niacinamide
Vitamin B3 at 4–5%. Up-regulates ceramide synthesis, regulates sebum, reduces erythema, and blocks melanin transfer to epidermal cells. One of the best-tolerated actives.
Exfoliation
Glycolic Acid
The smallest alpha-hydroxy acid. At pH 3.5–4.0 it dissolves desmosome bonds between corneocytes, accelerating desquamation and improving texture, tone, and downstream penetration.
Lipid Barrier
Ceramides
Constitute 30–50% of the stratum corneum lipid matrix. Replenishing them restores the moisture seal, reduces transepidermal water loss, and repairs barrier compromised by actives.
Mineral Protection
Zinc Oxide
Broad-spectrum mineral filter that reflects and scatters UVA + UVB immediately on application. No chemical absorption, no photo-sensitisation: the SPF of choice for reactive and post-treatment skin.
04 · Standards
Formulation Standards
Clinical Concentration
Actives formulated at the percentage shown effective in peer-reviewed studies, never a token inclusion for label appeal. Efficacy over marketing.
pH Optimisation
Each formula balanced to the pH at which its active remains stable and bioavailable: L-ascorbic acid below pH 3.5, AHAs at 3.5–4.0, niacinamide near pH 6.
Delivery Systems
Encapsulation, liposomal carriers, and penetration enhancers transport actives past the stratum corneum to the living layers where they actually work.
Barrier-First
Potency without compromise. Hydrators, ceramides, and soothing agents protect the barrier so actives can be used consistently without irritation.
Apply the Science
Explore SK1N's clinically formulated products, each selected for proven biological efficacy at its target layer.
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