Polyglutamic Acid Is the Hydrating Hero Ingredient Your Skincare Routine Needs

Woman with glass of water

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About a month ago I heard the words polyglutamic acid (PGA) for the first time. I was listening to Charlotte Tilbury talk about her latest product launches at a virtual event (because that's the new normal). Tilbury was extolling the virtues of this little-known ingredient as a hydrating hero. In fact, she is so enamored with it, she factored it into her Magic Serum ($80).

"Polyglutamic acid is a hydration powerhouse!" Tilbury tells Byrdie. "Polyglutamic acid is an incredible humectant that holds four times more moisture than hyaluronic acid (HA)—my skin just drinks it in!"

So why is an ingredient supposedly more moisture-banding than the hydration hero that is hyaluronic acid so little known? I called on Tilbury and scientist Michelle Wong of Lab Muffin Beauty Science to reveal more about the enigma that is polyglutamic acid. Plus, keep scrolling to shop the products that feature this buzzy skincare ingredient.



MAIN BENEFITS: Moisturizes skin, reduces the appearance of wrinkles and pores, replenishes cell moisture.

WHO SHOULD USE IT: It is ideal for anyone with dry or dehydrated skin. Polyglutamic acid is safe for all skin types, however, if you have sensitive skin it is always best to patch test a new product.

WHEN YOU CAN USE IT: Polyglutamic acid can be morning and night.

WORKS WELL WITH: It plays nicely with other skincare ingredients, especially hyaluronic acid and vitamin C.

DON’T USE WITH: There are no known negative reactions with polyglutamic acid.

What is Polyglutamic Acid?

"Glutamic acid is an amino acid. Polyglutamic acid is created when lots of glutamic acid molecules are linked together," says Wong. "It's produced by bacterial fermentation and is found in Nattō." [Ed note: Nattō is a traditional Japanese food made from fermented soybean.]

What Are the Skin Benefits?

"It's a very effective humectant that can grab onto water and keep skin hydrated," notes Wong.

"Polyglutamic acid helps seal the moisture in your skin, and enhances the skin’s elasticity," says Tilbury. "Part of the aging process involves the loss of HA in the skin, which is broken down by an enzyme called hyaluronidase. Products that contain PGA help to inhibit the action of hyaluronidase, resulting in more HA in the skin, and giving an overall moisturized, rejuvenated, and hydrated appearance to the skin."

Within her namesake brand's Magic Serum, Tilbury tells us that the PGA hydrates the skin, leading to a plumper-looking complexion and a diminished appearance of pores. "It makes makeup application so much easier too!" she adds.

How Does It Compare to Hyaluronic Acid?

"[Unlike HA], polyglutamic acid doesn't occur naturally in our bodies," Wong says. "Ingredient suppliers claim it can hold 10 times more water than hyaluronic acid, which is very impressive." Tilbury, on the other hand, claims it holds four times as much moisture because of its larger molecular size and can actually help the skin produce more hyaluronic acid. "Not only does it draw water into the cells, like HA, but it also forms a protective film on your skin that prevents water from evaporating," she claims. "I call it my plumper-looking skin filter!"

What both Wong and Tilbury do agree on is that polyglutamic acid is more effective at holding onto moisture than hyaluronic acid,—however, don't be so quick to abandon HA in favor of PGA. "I see the two ingredients as friends rather than competitors," says Tilbury. "When used together, they can be seen as the ultimate recipe for hydrated skin."

Why Is It Under-the-Radar?

Polyglutamic acid is relatively new on the beauty market, Wong tells us. According to Tilbury, it also costs more than HA, which affects profit margins and could be one of the reasons we haven't seen it in that many products to date.

Does Polyglutamic Acid Play Nice With All Skin Types and Ingredients?

"Yes, it mixes well with other products, especially water-based ones," says Wong.

Tilbury notes that "polyglutamic acid floods the skin with moisture—all skin types require hydration to function optimally but sensitive and dry skin types, in particular, will love the hydration boost this gives."

Is It Best Applied via a Serum?

Polyglutamic acid is mostly formulated into serum textures, and Wong tells us that "since it's a general humectant and effective at very low concentrations (as low as 0.1%), it can work well in lots of different formulations. Along with serums, it can be formulated into moisturizers, essences, toners, possibly even sunscreens though I don't know of any on the market yet."

"As more people learn about the benefits of PGA, it will gain the cult status of HA and we can expect to see it used in more products," predicts Tilbury. "I’m thrilled to have been one of the first to bottle this incredible, supercharged ingredient."

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