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Moumoujus

PCA.

Valuable CAS 98-79-3 / HUMECTANT, MOISTURISING

PCA, or Pyrrolidone Carboxylic Acid, predominantly utilized as its sodium salt (Sodium PCA), is a fundamental component of the skin's Natural Moisturizing Factor (NMF). It acts as a powerful humectant, efficiently attracting and binding moisture to optimize skin hydration and strengthen barrier integrity.

Summary

Humectant Skin-identical ingredient Barrier support Antioxidant Anti-inflammatory Hair conditioning Antistatic

Science

Mechanism of Action

As a key constituent, comprising 12-14%, of the skin's Natural Moisturizing Factor (NMF), Sodium PCA functions as an exceptional humectant. It effectively draws and retains atmospheric moisture within the stratum corneum, capable of binding up to 250 times its weight in water. This action significantly enhances skin hydration, elasticity, and smoothness, concurrently reducing transepidermal water loss (TEWL) and fortifying the skin’s barrier function. Sodium PCA also demonstrates anti-inflammatory properties that soothe irritation and redness, alongside antioxidant capabilities that neutralize free radicals, contributing to overall skin vitality. Its small molecular size facilitates effective penetration, ensuring sustained moisturization.

Research

Clinical Evidence

High confidence
Effective range 0.2–5%
Optimal

0.5-3%

Key findings

  1. 01 Demonstrated to enhance skin hydration by reducing transepidermal water loss (TEWL) by up to 25%.
  2. 02 Cosmetic formulations containing at least 2% of the PCA-NaPCA salt system effectively improved dry skin conditions in both short and long-term applications.
  3. 03 Proven effective in moisturizers, particularly when combined with urea, for treating dry skin in patients undergoing long-term systemic retinoid therapy.
  4. 04 Formulations incorporating Sodium PCA have shown improvements in hair texture.

Transparency

Dusting Analysis

Not commonly dusted

Sodium PCA is effective at concentrations as low as 0.5% and has a high safety profile, even at very high percentages. Its well-documented efficacy and broad usage suggest it is not commonly 'dusted' at ineffective levels in formulations.

The Formula

Formulation

Solubility
Water
Optimal pH 4.5 – 7
0 7 14

Stability

Sodium PCA exhibits stability across a wide range of temperatures and pH levels, with an optimal pH for stability typically between 4.5 and 7.0 (ideally 5-6). For optimal integration, it should be incorporated during the cool-down phase of formulation, once temperatures are below 40-45°C.

Synergies

  • Urea (for dry skin treatment)

Conflicts

  • N-nitroso compounds (e.g., DEA or TEA)

Safety

Safety Profile

CIR Status
Safe as used
Max tested
50%
Sensitization risk Low

The CIR Expert Panel consistently deems PCA and its salts safe for cosmetic use, noting Sodium PCA's non-irritating nature to skin and eyes at concentrations up to 50%, with no observed phototoxicity, sensitization, or comedogenicity. However, co-formulation with N-nitroso compounds like DEA or TEA should be avoided to prevent potential harm. EWG also assigns low concerns for toxicity. Mild irritation is exceptionally rare, typically occurring only at extremely high concentrations (≥6-12%) or with direct contact with undiluted powder in highly sensitive individuals.

Your Skin

Skin Compatibility

Yes Normal
Yes Dry
Yes Oily
Yes Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Verdict

Valuable

A highly effective, skin-identical humectant that significantly boosts hydration, supports the skin barrier, and offers anti-inflammatory and antioxidant benefits for all skin types, with excellent safety.

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