Polyglutamic Acid
A fermentation-derived polymer that forms a water-holding film on the skin surface.
Plausible and widely used, but the human evidence base is thin.
On the label: Polyglutamic Acid. Also known as PGA, Gamma-PGA, Natto gum.
What it does for you
Helps the hydration you apply stay put for longer.
Why we use it
It layers well with the hyaluronic acid system without competing with it.
Mechanism
A large, strongly water-loving polymer that binds water and forms a film, slowing evaporation. It is too big to penetrate meaningfully, and it is not meant to.
Commonly confused with
You will often see the claim that polyglutamic acid holds four to five times more water than hyaluronic acid. We cannot trace that figure to a peer-reviewed source, so we do not repeat it.