Introduction: The Hydration Debate
Hyaluronic acid (HA) has long been considered the gold standard for skin hydration, but in recent years, polyglutamic acid (PGA) has emerged as a promising alternative. Consumers and chemists alike are now comparing pga vs hyaluronic acid to determine which active offers better hydration, smoother texture, and long-term barrier support. This question is one of the most searched in skincare, and it is backed by increasing scientific research.
What is Hyaluronic Acid?
HA is a glycosaminoglycan naturally found in the skin’s extracellular matrix. It binds up to 1,000x its weight in water, making it a powerful humectant (PubChem).
- Forms in cosmetics: Sodium hyaluronate, hydrolyzed HA, crosslinked HA
- Molecular weights:
- High MW: forms a surface film, reducing TEWL
- Low MW: penetrates deeper for plumping
- Limitations: Can be unstable in low pH formulas, and some consumers experience “tightness” from large MW film-forming HA.
What is Polyglutamic Acid?
PGA is a biopolymer produced by fermentation of Bacillus subtilis. It consists of repeating glutamic acid units. Unlike HA, which occurs naturally in the skin, PGA is biotech-derived. Research shows it can hold up to 5x more water than HA (Journal of Cosmetic Dermatology).
- Film-forming: Creates a soft, flexible film on the skin, reducing water evaporation
- Barrier support: Stimulates natural moisturizing factors (NMFs) and improves elasticity
- Additional properties: May enhance delivery of other actives by modifying skin permeability
Scientific Evidence
- Studies show PGA significantly increases skin elasticity and hydration after 4 weeks of use (PubMed).
- Comparative testing confirmed PGA improved skin smoothness more effectively than HA alone.
- Clinical research also highlights HA + PGA blends deliver superior hydration compared to HA-only formulations (NCBI).
Key Differences: PGA vs HA
| Feature | Hyaluronic Acid (HA) | Polyglutamic Acid (PGA) |
|---|---|---|
| Source | Naturally found in skin (glycosaminoglycan) | Fermentation-derived polypeptide |
| Water-binding | ~1,000x weight | Up to 5,000x weight |
| Action | Humectant, plumps skin, reduces TEWL | Film-forming, boosts elasticity, supports NMF |
| Penetration | Depends on MW (low MW penetrates deeper) | Primarily surface hydration and barrier support |
| Added benefit | Viscoelasticity in dermis | Improves smoothness, enhances delivery of actives |
Cosmetic Applications
- HA-Focused Serums: Lightweight hydration with different MW fractions. See our guide on Barrier Repair Ingredients.
- PGA Barrier Creams: Long-lasting hydration and soft feel
- HA + PGA Hybrids: Synergistic formulas for intense, multi-level hydration
- Mask Formulas: Film-forming polymers (like PGA) lock in hydration during wear
Consumer Benefits
- PGA: Longer-lasting hydration, smoother skin, improved elasticity
- HA: Immediate plumping, fine-line reduction, deep hydration
- Both: Well-tolerated, vegan-compatible, and suitable for all skin types
Formulation Tips for Chemists
- Combine multi-weight HA with PGA for layered hydration.
- Use PGA in masks and leave-ons to maximize film-forming benefit.
- Pair with ceramides and niacinamide for barrier-focused formulations.
- Highlight consumer-friendly comparisons (“PGA holds more water than HA”) in marketing claims.
Regulatory Considerations
Both HA and PGA are safe for cosmetic use. Claims should remain cosmetic:
- “Boosts hydration”
- “Improves skin smoothness”
- “Helps strengthen the skin barrier”
Avoid drug-like claims such as “treats dryness disorders” or “heals eczema.”
Future Outlook
HA will remain a staple, but PGA is quickly rising as a complementary or alternative hydrator. For chemists, the winning approach is not PGA vs HA, but PGA + HA. Combining these polymers allows brands to deliver differentiated hydration products that stand out in a crowded market. As biotech fermentation expands, expect to see novel PGA derivatives with tailored film properties, opening new frontiers in hydration science.
