Polyglutamic acid is a high-performance humectant polymer derived from fermented soybeans that holds significantly more moisture than hyaluronic acid. This biopolymer forms a flexible, hydrating film on the skin surface to prevent transepidermal water loss while supporting the body’s natural moisturizing factors.
- INCI Name:
- Polyglutamic Acid
- Chemical/Scientific Name:
- Gamma-Poly-L-Glutamic Acid (γ-PGA)
- Common Aliases:
- PGA, Natto Gum (related concentrate), Sodium Polyglutamate
| Category: | Moisturizers |
| Source Origin: | Natural (Bacterial fermentation of Bacillus subtilis) |
| Comedogenic Rating: | 0 |
| Primary Industries: | Cosmetics, Medical Wound Care, Food Science |
| Solubility: | Water-soluble |
At a Glance: Properties & Effects
| Hydration/Moisture: | |
| Barrier Repair: | |
| Texture Enhancement: | |
| Irritation Risk: |
Primary Benefits:
- Provides intense surface hydration by forming a breathable film.
- Reduces the appearance of fine lines and wrinkles through plumping.
- Inhibits the breakdown of endogenous hyaluronic acid.
- Enhances the skin’s natural moisturizing factor (NMF) levels.
Potential Risks:
- May cause “pilling” when layered with certain silicone-heavy formulas.
- Highly concentrated serums may feel slightly tacky upon initial application.
Biological Action & Cosmetic Profile
Structurally, this polypeptide consists of multiple glutamic acid units linked via peptide bonds between amino and carboxylic acid groups. Because it possesses a high density of carboxyl groups, the polymer exhibits an exceptional capacity for hydrogen bonding with water molecules. Research indicates that specific molecular weights can sequester significantly more water than Sodium Hyaluronate, making it one of the most efficient humectants in modern cosmetology. By creating a smooth, hydrogel-like film on the stratum corneum, the molecule physically traps moisture and prevents it from evaporating into the environment.
Clinical studies emphasize that this ingredient serves a dual purpose by regulating enzymatic activity within the skin. It acts as a potent inhibitor of hyaluronidase, the enzyme responsible for degrading the skin’s natural moisture reservoirs. By limiting this enzymatic breakdown, the polymer helps maintain the structural integrity of the extracellular matrix. Furthermore, it has been shown to stimulate the production of PCA (pyrrolidone carboxylic acid), lactic acid, and urocanic acid, which are critical components of the skin’s natural moisturizing factor.
Broader Applications & Origins
Natural production of this biopolymer occurs during the fermentation of soybeans by Bacillus subtilis, a process historically used to create the Japanese food “natto.” In a cosmetic context, the material is purified to remove odors and soy proteins, leaving a clear, viscous liquid or powder. While its primary use is in skincare, the medical industry utilizes its film-forming properties for advanced drug delivery systems and specialized wound dressings that require a moist environment for tissue regeneration.
Routine Integration
Synergies:
- Sodium Hyaluronate: Combining these humectants provides multi-level hydration across different skin depths.
- Niacinamide: Enhances barrier function and improves overall skin texture.
- Glycerin: Works alongside the polymer to pull moisture into the deeper layers of the stratum corneum.
- Panthenol: Boosts the soothing and wound-healing properties of the formulation.
Conflicts:
- No known chemical contraindications; however, high molecular weight versions should be applied before heavy oils to ensure absorption.
Clinical Consensus & Safety
Dermatological assessments categorize this ingredient as non-sensitizing and safe for all skin types, including sensitive and reactive skin. The Cosmetic Ingredient Review (CIR) Expert Panel and various independent studies confirm that it lacks the potential for systemic toxicity or significant irritation at typical cosmetic concentrations (0.1% to 5.0%). Because it is a biodegradable biopolymer, it is also regarded as an environmentally sustainable alternative to certain synthetic thickeners and film-formers.
Is polyglutamic acid better than hyaluronic acid?
Rather than being “better,” it is complementary. While Sodium Hyaluronate penetrates deeper to hydrate from within, polyglutamic acid forms a superior protective film on the surface to seal that moisture in and prevent evaporation.
Can this ingredient cause acne or clogged pores?
No, this molecule has a comedogenic rating of 0. It is water-soluble and does not contain lipids or waxes that typically contribute to pore congestion, making it suitable for oily and acne-prone skin types.
Why does my product pill when using this?
Pilling usually occurs because the large molecular weight of the polymer creates a film that may rub off if it doesn’t bond well with subsequent products. To avoid this, allow the serum to dry completely before applying silicone-based primers or heavy sunscreens.