INCI: PCA - Also known as: Pyrrolidone Carboxylic Acid, Pidolic Acid, 2-Pyrrolidone-5-Carboxylic Acid

QUICK FACTS

What is PCA (Pyrrolidone Carboxylic Acid)?

PCA (pyrrolidone carboxylic acid), also known as pidolic acid, is a cyclic derivative of glutamic acid and one of the most abundant components associated with the skin's natural moisturizing factor (NMF). It is produced endogenously in the epidermis through the enzymatic breakdown of filaggrin - the structural protein responsible for bundling keratin filaments within the corneocyte. As filaggrin degrades during keratinocyte differentiation, it releases free amino acids and PCA into the stratum corneum, forming a significant portion of the NMF network associated with keeping skin hydrated and flexible.

In healthy, youthful skin, PCA is present at relatively high concentrations within the outermost layers, where it acts as a hygroscopic component - associated with drawing atmospheric moisture toward the corneocyte and contributing to the skin's moisture-retention environment. This natural process is associated with changes in aged skin, in individuals with filaggrin gene variants (commonly found in eczema-prone skin), and in anyone with a chronically compromised barrier.

At Sweet Chemistry, PCA is formulated alongside its sodium salt (Sodium PCA) and Sodium Lactate - completing a three-part NMF-restoring humectant system designed to closely mirror the biochemical composition of the skin's own moisture-retaining network.

What does it do for skin?

PCA functions as a hygroscopic humectant, associated with drawing water from the environment and from the deeper skin layers toward the stratum corneum. Its cyclic lactam structure is studied in connection with water-binding capacity, and its skin-identical character means it is designed to integrate naturally into the corneocyte's water-retaining environment without disrupting the barrier's pH or lipid organization.

Within the Sweet Chemistry water-based formulas, PCA works as part of a layered NMF approach that includes sodium PCA, sodium lactate, amino acids (including glycine, arginine, serine, and others), and four molecular-weight forms of sodium hyaluronate. Together these components are designed to recreate the full biochemical environment that healthy skin uses to self-hydrate - rather than relying solely on external film-forming agents to temporarily address dehydration on the surface.

Research has also explored PCA's contribution to the skin's mildly acidic environment. By helping to support the acidic conditions associated with the acid mantle, PCA may passively contribute to the pH environment in which barrier lipid-related and antimicrobial enzymes are studied to function best - making it a meaningful contributor to the overall surface environment beyond its direct humectant character.

FOUND IN

In 3 Formulas

PCA is present in all three Sweet Chemistry water-based formulas as part of a complete NMF-restoring humectant complex - formulated not as a standalone ingredient, but as one component of a designed system that mirrors the chemistry of healthy, hydrated skin.

Nourishment - All Skin Types

Barrier Repairing Hydra-Serum PCA - 1.0 oz / 30 ml

The Hydra-Serum pairs PCA with Sodium PCA, Sodium Lactate, eleven amino acids, and four forms of hyaluronic acid within a 40%-active emulsion. The Max Repair System's independent clinical study showed statistically significant improvement in skin hydration in 89% of subjects.

Hydration - Dry to Normal

Elasticity Reinforcing Hydra-Cream PCA - 1.7 oz / 50 ml

In the Hydra-Cream, the full NMF complex anchors the formula's hydration system within a 54%-water emulsion that also delivers peptides, ceramides, and vitamin C - combining active support with genuine moisture restoration.

Hydration - Dry to Dehydrated

Elasticity Reinforcing Lipid-Cream PCA - 1.7 oz / 50 ml

The Lipid-Cream pairs the NMF complex with shea butter, sea buckthorn, and jojoba seed oil for a hydration approach that addresses both the water-binding and lipid-barrier dimensions of chronically dry skin.

WORKS TOGETHER WITH

NMF Salt Sodium PCA

INCI: Sodium PCA.

The sodium salt of PCA, present alongside free PCA in all three water-based formulas, and studied for its water-binding properties. Synergy Note: Free PCA and Sodium PCA are naturally co-occurring within the stratum corneum's NMF - formulating both is designed to recreate the actual ionic environment the skin uses for its own moisture management.

NMF Lactate Sodium Lactate

INCI: Sodium Lactate.

The sodium salt of lactic acid and a key NMF component present alongside PCA in all three water-based formulas. Synergy Note: PCA and sodium lactate are co-occurring NMF components - together they represent two of the largest non-amino-acid contributors to healthy skin's intrinsic moisturization approach.

Amino Acid Blend Amino Acid Complex

INCI: Arginine, Aspartic Acid, Glycine, Alanine, Serine, Valine, Histidine, Phenylalanine, Isoleucine, Proline, Threonine.

A complete eleven-amino-acid NMF blend at 1% in all three water-based formulas. Synergy Note: Free amino acids account for approximately 40% of the NMF by composition; PCA accounts for another significant fraction. Formulating them together provides the two largest NMF fractions within a single hydration system.

Multi-Weight Hyaluronic Acid Sodium Hyaluronate Complex

INCI: Sodium Hyaluronate, Sodium Hyaluronate Crosspolymer, Hydrolyzed Sodium Hyaluronate, Sodium Acetylated Hyaluronate.

Four molecular-weight forms of HA present in all three water-based formulas. Synergy Note: PCA operates primarily within the stratum corneum; hyaluronic acid is studied in connection with reaching into the viable epidermis and upper dermis - together they are designed to create a multi-depth hydration approach that addresses both surface and structural moisture.