Humectant

Polyglutamic Acid

Reviewed by Daisy · Last updated 14 Aug 2026

Also known as: PGA, Gamma-Polyglutamic Acid

The super hydrator

Best For Skin Types

All skin types

Addresses

Dehydration, Fine lines

Effective Concentrations

0.1-2%

Usage Frequency

As directed on product packaging

What Is Polyglutamic Acid?

Polyglutamic acid (PGA) is a powerful humectant derived from fermented soybeans, specifically the traditional Japanese food natto. It has a larger molecular weight than hyaluronic acid, which allows it to form a moisture-retaining film on the skin surface.

Research has shown that PGA can hold up to 5 times more moisture than hyaluronic acid, making it one of the most hydrating ingredients available. It also inhibits the enzyme hyaluronidase, which breaks down natural hyaluronic acid in the skin, thereby boosting overall hydration levels.

Unlike hyaluronic acid which draws moisture from the environment (or deeper skin layers if humidity is low), PGA creates a protective barrier that prevents moisture loss while keeping the skin plump and hydrated.

PGA works well in combination with hyaluronic acid and other hydrating ingredients. It is suitable for all skin types, including oily skin, as it hydrates without adding heaviness.

Clinical Evidence & References

Polyglutamic acid (PGA) is a fermented soybean-derived humectant with a molecular weight larger than hyaluronic acid, enabling it to form a moisture-retaining film on the skin surface. Published research indicates it can bind significantly more water than hyaluronic acid and may inhibit hyaluronidase, an enzyme responsible for breaking down skin's natural hyaluronic acid. These mechanisms support its role in sustained hydration and skin plumping.

Evidence for PGA's efficacy is developing, with several peer-reviewed studies demonstrating measurable moisturising effects in human skin. However, the body of evidence remains modest in scale; most published work involves relatively small participant groups and short study durations. Individual tolerance and time-to-visible-effect may vary. Further research examining long-term use, optimal concentrations, and synergistic effects with complementary ingredients would strengthen the evidence base.

How to Use

Apply to damp skin before moisturizer.

Safety & Precautions

Very rare

Frequently Asked Questions

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