What it does
- Draws and holds water at the surface for immediate, lasting hydration and a plumped look.
- Forms a light moisture-retaining film.
- Often layered with hyaluronic acid for complementary hydration.
How it works
PGA is a biodegradable polymer of glutamic acid produced by fermentation. It is widely documented as a strong humectant that also forms a light surface film to reduce water loss, and it is often paired with hyaluronic acid, which hydrates at different depths.
Use level
- Typical use level
- typically 0.1–1%
Commonly used at 0.1–1%. Like other strong humectants it thickens water and can feel tacky at higher levels.
Formulation considerations
- Water-soluble; add to the water phase.
- Film-forming; adds a smooth after-feel.
- Pairs well with hyaluronic acid and other humectants.
What it pairs with & what to avoid
Pairs well with
- Hyaluronic acid, glycerin
- Occlusives and emollients to seal
Use with care / avoid
- High levels alone in very dry air without an occlusive
Regulatory status
Polyglutamic acid is listed in the EU CosIng database and is a well-established humectant.
Common questions
Is polyglutamic acid better than hyaluronic acid?
They are complementary; PGA forms a surface film and is often described as holding even more water, while HA hydrates at multiple depths. Many products use both.
What percentage of polyglutamic acid is used?
Typically 0.1–1%.
Is polyglutamic acid good for dry skin?
Yes, especially layered under an occlusive to lock in the water it attracts.