This fancy-sounding ingredient is definitely a byproduct of once you ferment soybeans. Primarily, “it is created when numerous glutamic acid molecules (an amino acid) are linked collectively,” notes board-certified dermatologist Hadley King, M.D. If that sounded too science-jargony, this is the breakdown: Amino acids are natural compounds which might be the constructing blocks of proteins in each crops and animals. “Amino acids play an instrumental position in some ways,” says board-certified dermatologist Keira Barr, M.D. “They’re concerned in lots of chemical reactions all through your physique to assist keep your physique’s regular capabilities, together with that of your pores and skin.” 

Because of this, they’re utilized in skincare—however there are numerous varieties of amino acids which might be extracted from a number of completely different sources (for skincare, the 2 most typical sources are soy and quinoa). When used topically, they’ll have quite a lot of capabilities: Some act as an antioxidant and neutralize free radicals, some encourage your physique to make its personal antioxidants, and others assist transport water, successfully performing as a hydrator. 

This ingredient falls into the final class as a humectant; humectants are courses of hydrators that work by drawing in and holding on to water molecules. “Polyglutamic acid is a strong humectant that may maintain 4 occasions extra water than hyaluronic acid,” says King. Hyaluronic acid, for reference, holds as much as 1,000 occasions its weight in water.