The professional skincare encyclopedia
Skinipedia,by MSTA.
Every treatment, condition, ingredient, device and brand in professional skincare, explained properly. Written and clinically reviewed by working practitioners, for the people who actually perform these treatments.
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33 entries live · 30 in writing
Conditions
- Acne vulgarisAcne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit, involving follicular hyperkeratinisation, sebum production, Cutibacterium acnes and innate immune activation. It presents as comedones, papules, pustules, nodules or cysts, most often on the face, chest and back.
- HyperpigmentationHyperpigmentation describes skin that appears darker than its surrounding baseline. It is a sign, not one diagnosis: melasma, post-inflammatory hyperpigmentation and solar lentigines have different patterns and causes, while a suspicious or uncertain focal pigmented lesion needs medical assessment first.
- Impaired skin barrierImpaired skin barrier is descriptive shorthand for reduced barrier function, not a validated diagnosis. Dryness, scaling, stinging or raised TEWL may accompany it, but none confirms it alone. Dermatitis, infection, rosacea and sensitive-skin syndrome each require their own assessment.
- MelasmaMelasma is a chronic, relapsing hyperpigmentation disorder causing symmetrical, irregular brown or grey-brown facial patches. Ultraviolet and visible light, hormonal influences and genetic susceptibility contribute, but its biology extends beyond excess melanin and no treatment reliably prevents recurrence.
- Post-inflammatory hyperpigmentation (PIH)Post-inflammatory hyperpigmentation is acquired darkening that remains after skin inflammation or injury. Increased epidermal melanin appears brown, while pigment released into the dermis can appear grey-brown or blue-grey and usually resolves more slowly.
- RosaceaRosacea is a chronic inflammatory condition of the central face. Two features are independently diagnostic: persistent centrofacial erythema with periodic intensification, and phymatous change. Flushing, telangiectasia, inflammatory lesions and ocular signs are not individually diagnostic.
In writing: Eczema (atopic dermatitis) · Keratosis pilaris
Treatments
- Chemical peelGuideA chemical peel is the controlled wounding of the epidermis, and sometimes the dermis, with a chemical agent. Peels are classified by the depth of that wound — superficial, medium or deep — which determines the indication, the downtime, the risk and the training required.
- DermaplaningGuideDermaplaning is manual exfoliation with a sterile blade held at an angle to the skin, removing stratum corneum and vellus hair. It gives immediate smoothness. Claims beyond that rest on a literature a published systematic review called scarce, anecdotal and not well documented.
- Jessner's solutionJessner's solution is 14% resorcinol, 14% salicylic acid and 14% lactic acid in ethanol. It is used alone as a superficial peel and as the keratolytic step before 35% TCA. The modified formula removes resorcinol and adds citric acid.
- LED light therapyGuideThe use of specific wavelengths of light to influence cellular activity in the skin, also called photobiomodulation. Red, blue and near-infrared wavelengths are used for different indications, commonly as a recovery or adjunct treatment.
- MicroneedlingGuideMicroneedling is a treatment creating controlled micro-injuries in the skin with fine needles, intended to trigger the wound-healing cascade and collagen synthesis. Depth, density and passes are selected by indication and anatomical site. Also called collagen induction therapy.
- Radiofrequency microneedlingGuideRadiofrequency microneedling combines microneedling with radiofrequency energy delivered through the needles, producing mechanical micro-injury plus controlled dermal heating. Because radiofrequency has no chromophore target, its heating is unaffected by skin colour.
- TCA peelA trichloroacetic acid peel destroys tissue by protein denaturation. Full-field use is commonly 10–35%; modern medium-depth technique uses an epidermolysis step then 35% TCA. High concentrations are focal techniques — CROSS, for individual atrophic scars — not stronger versions of a field peel.
In writing: BioRePeel · Extraction · Facial lymphatic drainage (MLD) · Microdermabrasion · Polynucleotides (PN) · Skin boosters
Devices & Technology
In writing: Cryotherapy (skin) · Dermalux · HydraFacial · Laser resurfacing · Morpheus8 · Radiofrequency (RF)
Ingredients & Actives
- Azelaic acidAzelaic acid is a topical dicarboxylic acid used in specific medicinal formulations for acne and papulopustular rosacea, with narrower off-label evidence for melasma and post-inflammatory hyperpigmentation. Results depend on the finished product and indication; direct human pregnancy and breastfeeding outcome data are sparse.
- CeramidesCeramides are a diverse family of sphingolipids that, with cholesterol and free fatty acids, organise the stratum-corneum permeability barrier. In skincare, 'ceramide' names an ingredient, not a guaranteed finished-product effect: performance depends on species, companion lipids, concentration, vehicle and tested population.
- ExosomesExtracellular vesicles are lipid-bilayer particles released by cells that cannot replicate. “Exosome” names those of demonstrated endosomal origin, not a size class. In professional skincare, EV-containing preparations are applied topically after procedures that open the skin.
- Glycolic acidGlycolic acid is the smallest alpha-hydroxy acid, used at roughly 3–10% in cosmetic products and 20–70% as a professional peel agent. It does not self-neutralise: the reaction continues until an alkaline neutraliser stops it.
- Lactic acidLactic acid is an alpha-hydroxy acid used at 5–12% in cosmetic products and from 10% to 92% as a professional peel. Lactate is also a genuine component of natural moisturising factor — which is a separate fact from what a free-acid peel does.
- NiacinamideNiacinamide, also called nicotinamide, is a form of vitamin B3 used topically for barrier, pigmentation, sebum and skin-ageing aims. Evidence exists across these areas, but effects are formulation- and outcome-specific; the breadth of research does not establish one universal concentration.
- RetinoidsRetinoids are vitamin A-related compounds used topically in cosmetics and medicines. Prescription retinoids have established roles in acne and photoageing; cosmetic retinol, retinaldehyde and retinyl esters require conversion or formulation-dependent delivery and do not inherit that evidence automatically.
- Salicylic acidSalicylic acid is lipid-soluble 2-hydroxybenzoic acid, marketed as a BHA but structurally a phenolic aromatic acid. Used at 0.5–2% in cosmetics and 20–30% as a professional peel, it is desmolytic rather than keratolytic and is removed at a timed endpoint rather than neutralised.
- Sunscreen and SPFSunscreen is a finished topical formulation that reduces ultraviolet exposure at the skin. SPF is the ratio of erythema-producing UV doses on protected and unprotected skin under a standard test; it does not state hours of safe exposure, or by itself quantify UVA protection.
- Tranexamic acidTranexamic acid is an antifibrinolytic medicine also used for melasma by oral, topical and intradermal routes. Oral use for melasma is off-label and prescriber-led. Topical formulations beat vehicle and match hydroquinone in trials, but recurrence after stopping is common by any route.
- Vitamin C (ascorbic acid)Topical vitamin C includes L-ascorbic acid and several distinct derivatives used for antioxidant, pigmentation and photoageing aims. L-ascorbic acid is biologically established but difficult to formulate; clinical outcomes depend on the exact molecule, vehicle, stability and finished-product evidence.
In writing: Growth factors · Hyaluronic acid · Peptides
Skin Science
- CollagenCollagen is the dominant structural protein of the dermis, providing tensile strength. Types I, III and V predominate in skin, and it turns over extremely slowly — a half-life estimated in years, not weeks. Most figures quoted about its loss and replacement do not survive checking.
- FibroblastThe fibroblast is the principal synthetic cell of the dermis. It produces collagen, elastin and the extracellular matrix — and also the matrix metalloproteinases that degrade them. Stimulating it is the stated mechanism behind most regenerative skin treatments.
- Fitzpatrick scaleThe Fitzpatrick scale classifies six skin phototypes by their tendency to burn and tan after ultraviolet exposure. It was not designed to classify ethnicity or visible skin colour, and practitioners should not use it alone to predict treatment risk.
- MelanogenesisMelanogenesis is the production of melanin within melanocyte melanosomes and its subsequent distribution to keratinocytes. It is regulated by genetic, ultraviolet, visible-light, hormonal and inflammatory signalling; excessive or persistent activation contributes to hyperpigmentation disorders.
- Skin barrierSkin barrier describes the skin's coordinated ability to limit water and solute loss while resisting entry of irritants, allergens and microbes. The stratum corneum supplies most permeability resistance, but viable epidermal junctions, surface chemistry and immune defences also contribute. It is a function, not a film.
- Stratum corneumThe stratum corneum is the outermost epidermal layer: flattened, anucleate corneocytes joined by corneodesmosomes and embedded in organised extracellular lipids. Its thickness and composition vary by body site. It is the principal physical substrate of permeability-barrier function, but it is anatomy, not every barrier process.
- Transepidermal water loss (TEWL)Transepidermal water loss is the rate of water vapour passing outward through a defined area of skin. It is a research measure of the stratum corneum's water-permeability barrier — not a measure of hydration, not a diagnosis, and not a universal 'damaged barrier' score.
- Wound-healing cascadeThe wound-healing cascade is the overlapping sequence — haemostasis, inflammation, proliferation and remodelling — by which skin repairs injury. Controlled activation of it underpins microneedling, resurfacing and peels. The phases overlap rather than following one another in blocks.
In writing: Contraindication · Patch test
Brands
In writing: AnteAGE · Circadia by Dr Pugliese · Cosmacure · Dermaceutic · Dermalogica · Medik8 · Mesoestetic · SkinBetter Science · SkinCeuticals · SkinPen · ZO Skin Health
Why we’re building this.
Our mission at MSTA is to raise the standard of professional skincare and aesthetic treatment delivered across this industry. Not just for the people who train with us — for everyone working in it, and for every client sitting in a treatment chair trusting that the person holding the device knows what they are doing.
Most skincare information online is written for consumers, by people who have never performed the treatment. Search anything technical — needle depths, peel neutralisation, erythema grading, the difference between a Jessner and a TCA — and you will find either nothing, or something written to sell you a product. That gap is not harmless. It is where poor practice comes from.
Skinipedia is our attempt to close it. It is built to be used at work: opened between clients, checked mid-consultation, read properly on the evening you decide you want to genuinely understand the treatment you have been performing for two years. Every entry is written by educators who deliver these treatments on real clients every week, clinically reviewed before publication, referenced where the science matters, and dated so you know how current it is.
When you understand a treatment at that level, everything downstream improves — the information you give your clients, the expectations you set, the contraindications you catch, and the results you are able to defend. That is the whole point of it.
It is free, it always will be, and it is deliberately useful to people who will never train with us.