PCA
Pyrrolidone carboxylic acid. A primary NMF component (~12%). Humectant, retains moisture in the stratum corneum.
Evidence by route
Topical application
Natural NMF component, effective humectant.
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Oily, Combination, Sensitive
About this ingredient
PCA (Pyrrolidone Carboxylic Acid) is a natural component of the skin's natural moisturizing factor (NMF). Makes up 12% of NMF in the stratum corneum. A derivative of the amino acid pyroglutamate. Mechanism. Strong humectant – binds water in the stratum corneum 3 times more efficiently than glycerin. Restores NMF deficit in dry skin, atopic dermatitis, xerosis. Maintains skin pH around 5.5. Where applied. Creams, serums, toners, shampoos (0.5–5%). Often in salt forms – Sodium PCA, Zinc PCA. In Spain in Sesderma, Martiderm, La Roche-Posay Lipikar lines. An alternative to hyaluronic acid for moisturizing effect. Evidence base. Tabachnick 1982 RCT (one of the first) showed 30% skin hydration increase in 7 days at 2% PCA. The Loden 2003 meta-analysis confirms PCA efficacy as a component of emollient therapy in atopy and xerosis. Safety. CIR confirmed safety. Hypoallergenic, non-comedogenic, does not photosensitize. Pregnancy and lactation – topically safe. Acceptable at any stage including face, breast, abdomen.
Frequently asked questions
Is PCA safe during pregnancy?
PCA is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is PCA for?
PCA suits: normal, dry, oily, combination, sensitive.
What is PCA and what does it do in cosmetics?
Pyrrolidone carboxylic acid.
What's the INCI name for PCA?
The INCI name is PCA. It may also appear as: Pyrrolidone Carboxylic Acid, L-PCA.
See PCA in a product composition right on the store page
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
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PEG-20, PEG-200, PEG-32, PEG-4, Sucrose, C12-13 Alkyl Glyceryl Hydrolyzed Hyaluronate, Fucose, Hydrolyzed Vegetable Protein
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