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PCA (Pyrrolidone Carboxylic Acid)

PCA (Pyrrolidone Carboxylic Acid) — a natural component of the skin's NMF (Natural Moisturizing Factor) formed from glutamic acid. One of the most effective natural moisturizers that replicates the skin's natural hydration. The sodium salt (Sodium PCA) is the main cosmetic form.

NMF componentnatural humectantSodium PCAhydration
✓ Safe
Comedogenic Rating
0/5
Irritation Potential
0/5

What is it?

PCA/Sodium PCA (INCI: Sodium PCA or PCA) — the sodium salt of 2-pyrrolidone-5-carboxylic acid. MW: 151.1 Da (PCA), 173.1 Da (Sodium PCA). Formed in vivo: spontaneous cyclization of glutamine and glutamic acid in corneocytes → PCA. Share in NMF: ~12% (along with lactates ~12%, amino acids ~40%, urea ~7%). Moisturizing mechanism: very hygroscopic (binds water better than glycerin at low humidity). Kosher and natural component — the synthetic version is identical to the natural one. pH-stable. Water-soluble. Colorless and odorless.

Moisturizing serums and creams, products for dry and atopic skin, NMF restoration products, hair care (moisturizing and conditioning).

Key Benefits

✦
NMF component — replicating the skin's natural hydration
Sodium PCA is one of the key components of NMF (Natural Moisturizing Factor) — an intracellular moisturizing complex in corneocytes. Normal NMF: maintains optimal hydration of SC and a content of 20-30% water by dry weight of SC. When NMF is disrupted (dry skin, atopy, aging): deficiency of PCA → reduced hydration. Topical Sodium PCA: replenishes the deficiency of NMF components → restoration of normal hydration. Advantage vs glycerin: at very low humidity (<50% RH) sodium PCA retains greater moisture in SC than glycerin. Clinical data: 2% sodium PCA — significant increase in corneometry over 4 weeks in xerosis.
◈
High hygroscopicity — effective humectant
Sodium PCA is one of the most powerful natural humectants — surpasses glycerin under certain conditions. Mechanism: residual carboxyl and cyclic amide groups → binding of water molecules through hydrogen bonds. Quantitatively: sodium PCA binds 5-10 water molecules per molecule. Hygroscopicity: better than glycerin at low humidity (relevant for dry climates). Synergy in humectant blend: sodium PCA + hyaluronic acid + glycerin = three-component moisturizing complex (each — different MW and mechanism). Additionally: sodium PCA interacts with hair keratin (ionic interaction) → moisturizing and softness of hair.
✧
Restoration of barrier function and protection from irritations
Sodium PCA supports the normal activity of SC enzymes (pH-dependent), which are functionally important for the barrier. Normal hydration of SC (provided by PCA) is necessary for: normal activity of serine proteases (SCCE, kallikreins) → proper exfoliation of corneocytes; activity of lipid enzymes → normal ceramide processing in lamellar bodies. In case of moisture deficiency: disruption of these enzymes → abnormal exfoliation, reduced barrier. PCA restoration: normalization of enzyme activity → improvement of the barrier. Anti-inflammatory support: maintenance of NMF → reduction of micro-injuries to the skin that provoke inflammation.

Suitable for

dry and dehydrated skinskin with atopic dermatitisnormal skin

Main Actions

✓ replication of NMF for natural skin hydration✓ exceptional hygroscopicity at any humidity✓ support of SC enzyme activity
Sodium PCA: natural and synthetic form

PCA = pyrrolidone carboxylic acid = 5-oxoproline. Sodium PCA = sodium salt (main form in cosmetics). Zinc PCA (INCI: Zinc PCA) — form for oily skin (antibacterial + moisturizing). Cosmetic Sodium PCA = synthetic, identical to the natural NMF component. INCI: Sodium PCA. Effective concentration: 1-5%. pH-stable 4-8. Water-soluble. Hygroscopic — may clump in dry form. Excellent in minimalist moisturizing formulas.

Frequently Asked Questions

What does PCA (Pyrrolidone Carboxylic Acid) do for skin?
Moisturizing serums and creams, products for dry and atopic skin, NMF restoration products, hair care (moisturizing and conditioning).
Who should use PCA (Pyrrolidone Carboxylic Acid)?
PCA (Pyrrolidone Carboxylic Acid) is suitable for: dry and dehydrated skin, skin with atopic dermatitis, normal skin.
Are there any warnings about PCA (Pyrrolidone Carboxylic Acid)?
PCA = pyrrolidone carboxylic acid = 5-oxoproline. Sodium PCA = sodium salt (main form in cosmetics). Zinc PCA (INCI: Zinc PCA) — form for oily skin (antibacterial + moisturizing). Cosmetic Sodium PCA = synthetic, identical to the natural NMF component. INCI: Sodium PCA. Effective

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