Polyglutamic Acid for Skin: Is It Better Than Hyaluronic Acid?

Another day, another new skin-care ingredient—it’s a tale as old as, well, moisturizer. But while many buzzy, up-and-coming actives tend to have more hype than hard data behind them, polyglutamic acid for skin is one of the few trends that actually has some credibility to back up its efficacy. Some even claim that it has quadruple the hydrating power of hyaluronic acid—able to hold up to 4,000 its weight in water—and while that’s not exactly true, there is a lot to love about it. (Long story short: That was in a lab setting, per one study, but there’s never been a head-to-head comparison between hyaluronic and polyglutamic acids in skin.)

For the uninitiated, polyglutamic acid (or PGA) is a peptide chain of glutamic acid, a type of amino acid, that’s derived from fermented soybeans. “It acts primarily as a humectant, binding and retaining water at the skin’s surface, like a hydrating sponge that leaves skin feeling softer and smoother,” says Taryn Huizenga, MD, a board-certified dermatologist in New York, NY. That’s why you may often spot it in hydrating serums and peptide formulas on the shelf.

Vogue’s Favorite Polyglutamic Acid Products:

• Best Overall: Byoma Phyto Mucin Glow Serum, $16
• Best Drugstore: Cetaphil Deep Hydration Water Gel, $22
• Best for Sensitive Skin: Prequel Skin Multi Quench Hydration Plumping Serum, $29
• Best for Dry Skin: Dermalogica Circular Hydration Serum, $69
• Best for Mature Skin: Skinfix Barrier+ Triple Lipid Activating Serum, $69
• Best for Dehydrated Skin: The Inkey List Polyglutamic Acid Serum, $17

PGA is also relatively large—which in this case, is a big bonus. “Because the molecule is so big, it mostly stays on the surface, where it leaves a light, flexible film that helps slow down water loss,” says Aderonke Obayomi, MD, a board-certified dermatologist in New York City. So it both pulls water into the surface layers of skin and, by forming that film, keeps water from evaporating. As a result, “what you actually see is skin that looks smoother and plumper and feels more comfortable, and fine lines caused by dehydration look softer,” she says.

There’s another advantage to be had with PGA. In addition to its hydrating properties, “it also inhibits hyaluronidase, the enzyme that breaks down your skin’s own hyaluronic acid,” says Asmi Berry, DO, a board-certified dermatologist in Los Angeles, CA. “So it’s not just hydrating. It’s helping protect the hydration you already have.” (That said, that’s mostly drawn from laboratory evidence, and there’s still a need for clinical evidence to show that this happens in the skin.)

But back to hyaluronic acid: There are a lot of similarities between the two, namely in terms of hydration. So, which is better—hyaluronic acid or polyglutamic acid? Hyaluronic acid has much more clinical evidence behind it, so it remains the gold standard for those who need hydration, according to Dr. Berry. Still, there’s room for PGA. “I think of them as complementary ingredients rather than one being inherently better than the other,” says Dr. Huizenga. Both are humectants that act as moisture magnets, tend to be gentle, and work for most skin types. “The difference is that PGA is a larger molecule that sits on the surface and forms that moisture-locking film, and a lot of people find it feels less tacky than hyaluronic acid,” says Dr. Obayomi. For that reason, she recommends pairing them: Apply a hyaluronic acid serum first, follow it with a PGA serum, and then apply your face moisturizer.

For those in need of extra hydration and plumping, PGA is fairly easy to incorporate. First, don’t worry too much about the percentage of PGA in a given formula. “There is not currently good clinical evidence that higher concentrations translate into proportionally better results,” says Jenna Queller, MD, a board-certified dermatologist in Boca Raton, FL. “The overall formulation and consistent use matter more than the percentage on the label.”

Moreover, polyglutamic is non-reactive, “meaning it does not interfere with other ingredients,” says Dr. Berry. “It layers well with actives that tend to compromise the skin barrier like retinoids, vitamin C, and exfoliating acids because it supports the skin and adds hydration.” Scroll ahead for the best products if you’re ready to add polyglutamic acid to your skin-care routine.

Best Overall: Byoma Phyto Mucin Glow Serum

• Why We Love It: Byoma’s serum calls on vegan ingredients, among them polyglutamic acid, to replicate the soothing, hydrating effects of snail mucin—thereby delivering glass skin. But it stands out from the crowd by supplementing that PGA with complementary ingredients, yielding long-lasting radiance and moisture. “It pairs PGA with ceramides and hyaluronic acid, so you’re getting surface hydration and barrier support in the same step,” explains Dr. Berry, who considers this formula an especially good option for those who have sensitivity or a compromised skin barrier. It’s also fragrance-free and doesn’t pill, making it ideal for layering beneath makeup.
• Key Ingredients: Polyglutamic acid, glycerin, hyaluronic acid, palmitoyl tripeptide-1, panthenol, ceramide NP
• Size: 1.01 fl. oz.
• Best For: All skin types, especially sensitive skin

Best Drugstore: Cetaphil Deep Hydration Water Gel

• Why We Love It: Cetaphil’s take on PGA for skin is proof that comprehensive hydration doesn’t necessarily require a heavy feel or sticky residue. This gel-like moisturizer is weightless and absorbs quickly, thanks to a strategic pairing of PGA and hyaluronic acid, which is part of the reason Dr. Huizenga likes it. Plus, “it’s lightweight, oil-free, and won’t clog pores, but still feels genuinely hydrating,” says Dr. Huizenga. But it’s not only about the instant results: The hydrating ingredients are gradually released, which allows them to keep skin comfortable and plump for a longer period of time.
• Key Ingredients: Polyglutamic acid, hyaluronic acid, panthenol, niacinamide, allantoin, glycerin
• Size: 1.7 fl. oz.
• Best For: All skin types, including oily skin

Best for Sensitive Skin: Prequel Skin Multi Quench Hydration Plumping Serum

• Why We Love It: This dermatologist-formulated serum goes above and beyond mere polyglutamic acid. It harnesses polyglutamic acid in multiple molecular weights, which work in tandem to plump skin and support skin’s Natural Moisturizing Factors (compounds that also keep skin hydrated), along with 10% glycerin, a well known and time-tested humectant. What’s more, a blend of organic compounds (called osmolytes) helps balance water levels in the skin, keeping it comfortable and hydrated throughout the day. Despite its impressive performance, it’s gentle: It has a Seal of Acceptance from the National Eczema Association, which indicates that it’s been vetted for safety and sensitization by a team of experts.
• Key Ingredients: Polyglutamic acid (1%), PGA Complex (3%), glycerin (10%), ectoin
• Size: 1.7 fl. oz.
• Best For: All skin types

Best for Dry Skin: Dermalogica Circular Hydration Serum

• Why We Love It: Dermalogica’s “Circulation” serum is named for its goal: to provide lasting hydration by bolstering the skin barrier, creating a beneficial “circulation” of hydration within the skin. It uses hyaluronic acid and an algae extract to hydrate skin, while polyglutamic acid boosts skin’s supply of water from within. A combination of sugars and amino acids, meanwhile, trap water on the surface of skin, minimizing water loss so skin stays hydrated and plump for a longer period of time. On top of that, “the combination with lactic acid means you’re getting cell turnover at the same time you’re locking in moisture,” says Dr. Berry. It does contain essential oils, so proceed with caution or consider patch-testing if you have a sensitivity.
• Key Ingredients: Polyglutamic acid, lactic acid, hyaluronic acid, glycerin, sea kelp extract
• Size: 1.0 fl. oz.
• Best For: Dry or dehydrated skin

Best for Mature Skin: Skinfix Barrier+ Triple Lipid Activating Serum

• Why We Love It: A boon for your skin barrier, this robust formula brings together several powerful ingredients. There’s polyglutamic acid, of course, as well as a lineup of lipids that mirror the composition of skin’s own moisture barrier. Also inside is niacinamide to brighten, glycerin and red algae (which serve as humectants), and multiple peptides that boost firmness and support elasticity. This combination makes it an especially good pick for those dealing with signs of aging like wrinkles, dark spots, and sagging skin, in addition to the dryness that can naturally occur over time or in cooler weather.
• Key Ingredients: Polyglutamic acid (3%), ceramides, sterols, fatty acid, peptides, niacinamide, glycerin, red algae extract
• Size: 1 oz.
• Best For: Mature skin, as well as most skin types

Best for Dehydrated Skin: The Inkey List Polyglutamic Acid Serum

• Why We Love It: For those seeking immediate plumping, the Inkey List’s formulation offers “a 3% PGA complex along with glycerin and a lightweight silicone base,” says Dr. Queller. “It provides an immediate plumping and smoothing effect, but I consider it a hydration step, not an anti-aging treatment.” Also inside the formula is Invisaskin, a trademarked ingredient that creates an undetectable film over skin to further bolster hydration. And there’s no fragrance, although it has a smell that might be polarizing for some. Ultimately, “it’s a straightforward formula, no unnecessary extras, and it does exactly what it promises at an affordable price point,” says Dr. Berry, who considers it the easiest entry into PGA because of its price tag and minimalist formulation.
• Key Ingredients: Polyglutamic acid (3%), Invisaskin (2%), glycerin, rice bran extract
• Size: 1.0 fl. oz.
• Best For: Dehydrated skin, all skin types