Last edited and fact-checked by Ana Vasilescu.
- Polyglutamic acid is a peptide that acts as a humectant to draw moisture into the skin
- It can be made synthetically or extracted from fermented soybeans
- The benefits of polyglutamic acid for the skin include increasing hydration, accelerating wound healing, and plumping wrinkles look
- It’s gentle and can be used twice daily
- Polyglutamic acid can be paired with any skincare active, including hyaluronic acid, retinol, niacinamide, glycolic acid, and vitamin C
Ferments are one of the best Asian beauty innovations, and polyglutamic acid is one that stands out. While it’s not the most popular ingredient in the skincare scene, this guy is the OG of moisturizers and even rivals the likes of hyaluronic acid and other beloved humectants. It could soon spice up your beauty routine. So what drives this humble ferment’s claim to fame, and why it deserves a spot on your skincare cabinet?
What is polyglutamic acid?
Polyglutamic acid (PGA) is a polymer of glutamic acid, an essential amino acid your body uses to make proteins. Technically, PGA is formed by linking together multiple molecules of amino acids, which means it’s practically a polypeptide. While it can be produced synthetically, PGA is also often extracted from the fermentation of bacteria (mostly from soybeans) and purified to obtain a form that can be used in skincare products.
So what’s so coveted about polyglutamic acid that beauty junkies can’t get enough of it? For starters, its water binding capacity. Although it has tough competition in the world of moisturizers, PGA is one of the most potent humectants (compounds that retain moisture) that can help to plump and hydrate the skin. To put this into perspective, it can hold up to 5,000 times its own weight in water. This is about four times more than the water-binding capacity of hyaluronic acid.
But here’s the scoop: this moisture booster has too large molecules to penetrate the skin, which means it’s most effective for surface-level hydration. Instead of sinking into the skin, it sits on top of it, where it forms a thin film that helps seal moisture and prevent water loss. It does that while also attracting water from the air.
While PGA is a standout ingredient for hydration, it can also provide additional benefits for the skin. Here’s what else it can do:
What are the benefits of polyglutamic acid for the skin?
- Increases hydration: Polyglutamic acid is a humectant with water-binding and moisture-retaining properties. Because it attracts water and seals it at the same time, it’s one of the most effective ingredients to hydrate the skin.
- Boosts NMFs: It was found that topical use of polyglutamic acid can increase the production of natural moisturizing factors (NMFs) such as pyrrolidone carboxylic acid (PCA) and lactic acid—all needed to maintain overall skin integrity.
- Anti-aging: PGA is especially effective at taming fine lines that develop from dehydration. Its film-forming properties also have a plumping effect on the skin and can help diminish the appearance of wrinkles by making them appear fuller. Interestingly, PGA improved the hydration and elasticity of the skin more than collagen and hyaluronic acid during a 28-day period study.
- Speeds up healing: Before its fame in skincare, polyglutamic acid was first popularized for its healing effects and used in medicine to accelerate the recovery of wounds and burns.
- Reduces hyaluronic acid degradation: By using products with polyglutamic acid, your skin can keep itself elastic from within as PGA inhibits the enzyme hyaluronidase, a big baddie for age-related hyaluronic acid loss. The result is better moisture retention and faster healing for healthier skin.
- Primes the skin: PGA makes a good primer for other products, like vitamin C or retinol serum. It improves the efficacy of active ingredients in skincare formulations by allowing them to penetrate the skin more effectively.
FIY, polyglutamic acid is also eco-friendly and biodegradable, making it a sustainable choice for conscious consumers.
Side effects and other concerns
Polyglutamic acid is a fairly safe ingredient that’s gentle, stable, and non-irritating. It’s not been shown to react with other skincare products, and its gentle hydration pairs well with more sensitizing actives. Reactions are rare; however, possible side effects caused by polyglutamic acid can include itchiness and redness. We always recommend patch test new products, especially since dehydrated skin is more at risk for sensitivity and reactions.
Living in a dry climate? There’s a chance polyglutamic acid can have the opposite effect and exacerbate dryness. Due to its humectant nature, it may draw moisture from deeper skin layers to the surface, only to evaporate and leave your skin even more dehydrated. This happens when humidity is low (under 70%), which is more likely to happen in winter.
But don’t quit the idea of using polyglutamic acid products. Even if you live in a dry climate you can benefit from this humectant without risking drying your skin. Simply apply a cream or ointment with occlusives after your PGA product. Occlusives like petrolatum, shea butter, and squalane coat the skin’s surface with a protective layer to reduce transepidermal water loss and seal moisture. Although PGA can act as a lightweight occlusive on its own, it’s better to follow up with other moisture sealers to ensure every drop of water is locked in.
How to use polyglutamic acid
While just slathering yourself in everything PGA might be tempting, stick to quality formulations. The most effective skincare comes from serums infused with 0.2-3% polyglutamic acid, with higher concentrations taking the best advantage of its hydrating properties.
As a humectant, it’s essential to apply PGA to a damp face, especially if you live in dry climates with low humidity or when your skin is craving extra hydration in winter. Try using polyglutamic acid during the moisturizing steps of your routine; this helps sink in creamy products as PGA can act as a breathable occlusive. It’s also great for stretching out your usage of more expensive products since it maximizes product absorption and can amp up their effectiveness.
PGA serums are also often used in skin flooding, along with other humectants like hyaluronic acid. This is a technique born from a TikTok-inspired trend that implies saturating the skin with intense moisture. It’s basically done by applying a serum with humectants and topping it with an emollient cream or occlusive moisturizer. This way, you give your complexion maximum hydration and lock it in for long-lasting effects.
What can you pair polyglutamic acid with?
Super-compatible with your current routine, polyglutamic acid plays well with just about every product. Day or night, this hydrator can boost the absorption and activity of some of your favorite actives, including vitamin C and exfoliants like lactic and glycolic acids.
Pair polyglutamic acid and niacinamide to lock in moisture and enhance skin elasticity. For intense moisture, team up PGA with hyaluronic acid. Don’t miss out on the peptide’s healing effects; they are a game-changer when combined with polyglutamic acid. Finally, PGA and retinol work wonders together to minimize retinol irritation and intensify that new skin glow.
Who should use polyglutamic acid?
Polyglutamic acid in skincare is universal and is the kind of ingredient that is suitable for everyone. It works great on dry, dehydrated, and tight skin, as well as on mature skin looking to diminish fine lines and wrinkles. For those with sensitive skin, polyglutamic acid can be a good alternative to hyaluronic acid and other hydrating ingredients that may cause irritation or redness. It goes well on oily complexions prone to acne, too, since it’s lightweight, non-sticky, and doesn’t clog pores.
We answer all your questions about polyglutamic acid
- Is polyglutamic acid better than hyaluronic acid?
While both function as humectants and help seal hydration in the skin, polyglutamic acid is thought to hold five times more moisture than hyaluronic acid. However, that doesn't necessarily mean polyglutamic acid is better than hyaluronic acid, and there's no study to compare them directly. For the best results, use both ingredients together to boost hydration levels to the maximum.
- Can you use polyglutamic acid every day?
Yes, polyglutamic acid gives the best results when used twice a day, in the morning and night routines.
- Does polyglutamic acid repair the skin barrier?
Polyglutamic acid protects the barrier function by forming a protective layer on the outermost skin layer to reduce water loss.
- Is polyglutamic acid good for sensitive skin?
PGA restores the moisture barrier and reduces inflammation, which can be especially beneficial for sensitive skin prone to redness.
Read next: 10 Best Polyglutamic Acid Products for Long-Lasting Hydration
Women’s Concepts uses reliable sources, including dermatologists’ insights, clinical trials, and scientific journals, to find accurate information and support all the facts shared in our articles. All statements and claims have clear and legit references. Read our editorial policy to learn more about our sources of information, our process of researching and fact-checking the content, and how our team strives to keep all articles updated, completed, and trustworthy.
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- Lee, Na-Ri et al. “In vitro evaluation of new functional properties of poly-γ-glutamic acid produced by Bacillus subtilis D7.” Saudi journal of biological sciences vol. 21,2 (2014): 153-8. doi:10.1016/j.sjbs.2013.09.004
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