What You Need to Know About Polyglutamic Acid for Skin

We're already big fans of hyaluronic acid, a sugar molecule that your body naturally produces and that's a common ingredient used in skin care to boost hydration. The ingredient has been lauded by scientists for its ability to hold 1,000 times its weight in moisture.

But another is even stronger: polyglutamic acid, which holds up to 5,000 times its weight in moisture. It comprises amino acid chains derived from fermented soybeans and, like hyaluronic acid, is a humectant.

"A humectant attracts moisture from the surrounding environment and retains it to deliver hydration," explains dermatologist David Kim, M.D. By holding on to water, polyglutamic acid plumps the skin to diminish fine lines and boost elasticity for a younger-looking complexion.

Polyglutamic acid can also inhibit an enzyme called hyaluronidase, which breaks down the hyaluronic acid in the deeper layers of your skin, says Dr. Kim. "By protecting your hyaluronic acid supply, polyglutamic acid can help keep you from going dull and dry and instead make you look fresh and healthy," says dermatologist Dhaval Bhanusali, M.D. "It also increases production of other moisturizing acids, like urocanic acid and lactic acid," Dr. Kim adds.

If you typically have dry or dehydrated skin, use both hyaluronic and polyglutamic acids for a powerful punch of moisture. If you're oily, go with just polyglutamic acid to keep skin in balance. Dr. Bhanusali recommends using the acids in the form of serums, which contain the highest levels of the active ingredients. Pat the liquids into skin before applying your daily moisturizer. (Important note: "Hydrating" and "moisturizing" mean very different things in skin care.)

Find polyglutamic acid in products like Then I Met You The Giving Essence (Buy It, $50, thenimetyou.com), Inkey List Polyglutamic Acid serum (Buy It, $15, sephora.com), and Charlotte Tilbury Magic Serum Crystal Elixir (Buy It, $80, sephora.com), which also contains hyaluronic acid.

But remember, it takes a team to stay moisturized. Amp up your overall hydration by adding these products to your arsenal as well.

• Propylene Glycol is ideal for dry eyes. Try Systane Hydration Preservative-Free Dry Eye Relief drops (Buy It, $19, target.com).
• Squalane strengthens your skin's protective barrier so moisture can't leak out. Try Biossance Squalane + Zinc Sheer Mineral Sunscreen (Buy It, $30, sephora.com).
• Glycerin is a humectant that attracts and holds water in your skin. Try La Roche-Posay Cicaplast Baume B5 (Buy It, $15, dermstore.com).