What it is
Polyglutamic acid is a water-soluble polymer built from repeating glutamic acid units, often produced by fermentation. In sunscreens and skincare it acts as a strong humectant that attracts and holds water and can form a light surface film that improves the feel of the formula. It is valued for adding hydration and a smooth finish.
Safety & warnings
Polyglutamic acid is generally well tolerated and is not a recognized allergen or comedogenic ingredient. As a large water-soluble polymer it tends to stay on the skin surface, and tolerability in a finished product depends on the overall formulation.
Origin & sourcing
It is typically produced by microbial fermentation, in which bacteria such as Bacillus species synthesize the glutamic acid polymer, which is then purified for cosmetic use.
Questions everyone asks
What does polyglutamic acid do for skin?
It is a humectant that draws and holds water at the skin surface and can form a light film, helping the product feel hydrating and smooth.
How is it different from hyaluronic acid?
Both are humectant polymers used for hydration, but they are chemically different. Polyglutamic acid is a glutamic acid polymer, while hyaluronic acid is a polysaccharide, and they are sometimes used together.