Polyglutamic acid: Is this the new moisturizer that truly beats hyaluronic acid?
You may have seen it listed on the labels of serums and moisturizers, often accompanied by an impressive claim: hold up to 5,000 times its weight in water, which is far more than hyaluronic acid. That’s enough to make polyglutamic acid (PGA) the new hero of hydration.
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Follow Beautydecoded on Google →But behind that spectacular figure, what do we really know? Here’s what the science says—and what needs to be put into perspective.
📌 See also: Hyaluronic acid: Real Benefits and How to Use It
What is polyglutamic acid?
Polyglutamic acid is a biopolymer, that is, a long chain of glutamic acid, a common amino acid. The form used in cosmetics is the poly-γ-glutamic acid (γ-PGA), produced by bacterial fermentation. It occurs naturally in the natto, this Japanese dish made from fermented soybeans with a stringy texture.
In cosmetics, it appears on ingredient lists under the names Polyglutamic Acid or Sodium Polyglutamate.
How does it affect the skin?
Three mechanisms are generally cited.
1. A powerful humectant. Like hyaluronic acid or glycerin, PGA attracts and retains water. In laboratory tests, it can bind up to 5,000 times its weight in water, compared to about 1,000 times for hyaluronic acid.
2. A moisturizing film on the skin's surface. It forms a light film on the skin, which limits water evaporation (insensible water loss).
3. A possible protective effect on hyaluronic acid. PGA is believed to inhibit the enzyme hyaluronidase, which breaks down the hyaluronic acid naturally present in the skin. Research also suggests that it may stimulate certain components of the natural moisturizing factor (PCA, lactic acid, urocanic acid).
What the Studies Say
The data exists, but it remains limited.
- A study involving volunteers compared a formula containing 0.2 % of PGA with a formula containing 5 % of glycerin, each applied to one forearm: the PGA formula produced good hydration results despite its much lower concentration.
- One study reported that, over 28 days, PGA improved skin elasticity more than collagen and hyaluronic acid.
- Healing properties have also been mentioned in the literature.
A Critical Eye: Why It's Important to Keep a Cool Head
At Beauty Decoded, we prefer to be straightforward.
- The figure «5,000 times» comes from the lab. It depends on the pH, the salt content of the gel, and the measurement conditions. In a real cream, applied to real skin, we are very far from these ideal conditions.
- No studies directly compare PGA and hyaluronic acid under robust clinical conditions. To say that one «beats» the other is therefore an overgeneralization.
- The inhibition of hyaluronidase has been demonstrated primarily in the laboratory. Its actual effect on the skin's hyaluronic acid reserves, when applied topically, has not been established.
- The studies are small in scope and often linked to industry stakeholders. Few independent trials, small sample sizes, short durations.
- «Anti-wrinkle» claims should be taken with a grain of salt. An effective moisturizer reduces fine lines caused by dehydration, but this is only a temporary effect—not a treatment for aging.
In short: the PGA is a A good moisturizer, well-tolerated, and promising. It hasn't been proven to be a revolution.
Who is it for, and how do you use it?
PGA is generally well tolerated and compatible with most active ingredients (retinol, niacinamide, vitamin C, exfoliating acids). It may be suitable for dry, dehydrated, or sensitive skin that does not tolerate certain moisturizers well.
Some practical tips:
- Apply it to slightly damp skin, like any humectant, so that it has water to absorb.
- Pair it with a cream To lock in moisture: A humectant alone can, in very dry air, end up drying out the skin.
- Morning and evening, with no specific restrictions, with or without hyaluronic acid.
Visit concentration is rarely listed on products, which makes it difficult to compare them: a serum that lists «PGA» at the end of the ingredient list will not produce the same results as a product where it appears at the beginning of the list.
Which products contain polyglutamic acid?
PGA is most commonly found in affordable serums and creams. Here are three products available at Sephora France, along with what you need to know about their formulas (approximate prices as of October 2026; subject to change).
| Product | What the Brand Says | Price guide | What You Need to Know |
|---|---|---|---|
| The INKEY List, Polyglutamic Acid Serum (30 ml) | A 3:% complex of polyglutamic acid, claimed to retain four times as much water as hyaluronic acid | about 17 € | The 3 % refers to a complex, not pure PGA. It appears in the 9th position on the INCI list. It has a silky, silicone-based texture and works well under makeup. |
| Sephora Collection, Hydrate, Plumping Hydrating Serum | Hyaluronic acid + polyglutamic acid combination, 2 % total, 97 % of naturally derived ingredients | about 20 € | PGA appears at the very end of the INCI list, so it makes up only a small portion of the formula. A short, silicone-free formula. |
| Sephora Collection, Glow, Vitamin C + PGA Radiance Gel-Cream | Vitamin C for radiance, PGA to strengthen the hydrolipid barrier | €15 to €17, depending on the format | PGA is a secondary ingredient here: the main benefit comes from vitamin C. |
To compare other products, check out the PGA's position in the INCI list : The higher it is on the list, the higher its concentration. If it’s at the bottom of the list, the moisturizing effect will come mainly from glycerin, hyaluronic acid, or other humectants in the formula.
Our verdict
Polyglutamic acid is a powerful humectant : It moisturizes well, is well-tolerated, and blends easily with the rest of a skincare routine. But the idea that it «outperforms» hyaluronic acid is based mainly on lab data and marketing.
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