Derived from a traditional Japanese food made of fermented soybean seeds known as nattō, polyglutamic acid is used as a moisturizing agent in facial and body care. In this article, discover our advice on how to effectively incorporate this active ingredient into your routine.
How to use polyglutamic acid?
Summary
Published on March 2, 2022, updated on June 15, 2025, by Maylis, Chemical Engineer — 4 min of reading
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Polyglutamic Acid, in brief.
Thepolyglutamic acid (PGA) is a biopolymer first isolated from the organism of the marine jellyfish. It allows it to store water in its delicate tissue, thus preventing accelerated dehydration due to its presence in the ocean's salty water. Today, PGA is extracted from a traditional Japanese food, the nattô, composed of fermented soybean seeds. It can also be biosynthesized from L-glutamic acid using the Gram-positive bacterium Bacillus subtilis.
From a chemical perspective, polyglutamic acid is apolymer derived from the amino acid glutamic. Its empirical formula is written as (C5H7NO3)n.In cosmetics, it is recognized for its hydrating action. It is capable of forming a protective film on the skin's surface that limits water evaporation. This is referred to as amicrogel; this structure swells and traps water, thus promoting its retention.Polyglutamic acid can retain up to 5,000 times its weight in water.
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The various treatments with polyglutamic acid.
In order to hydrate the skin and thereby prevent the appearance of wrinkles and fine lines, various formulations contain polyglutamic acid and are now distributed in the cosmetic market. This active ingredient can thus be found in creams, lotions, and aqueous serums.
For effectiveness on the skin, polyglutamic acid must be concentrated at a minimum of 0.3% in a cosmetic formula. Generally, serums are the formulations that have a higher concentration of active ingredients, and therefore, of PGA. However, it is advisable not to exceed 3% of PGA in a skin product. An overdose of polyglutamic acid can weaken the epidermal tissues and promote the appearance of redness. Therefore, its pure use is not recommended. Being an acid, a patch test on the inside of the elbow is recommended before any use. In case of intolerance, avoid using care products containing polyglutamic acid.
How to incorporate polyglutamic acid into a daily routine?
Areas of Application :
A polyglutamic acid treatment can be applied to the entire face avoiding the mouth, lips, or eyes. It can also be used locally, solely on areas affected by intense dryness as a spot treatment.
Application Frequencies :
Polyglutamic acid is not a photosensitizing agent: it does not increase skin sensitivity to the sun's UV rays. Thus, you can apply a skincare product containing this active ingredient morning and evening. However, make sure to protect your skin every morning with a broad-spectrum sunscreen.
Application methods according to the galenics used :
Generally, serums are more concentrated in active ingredients than creams.To apply a serum, pour 3 to 7 drops into the palm of your hands. Using your fingertips, apply the treatment evenly across your face and neck. Massage gently. When it comes to applying a polyglutamic acid cream, take a small amount of the product and spread it over your entire face. Allow it to penetrate by massaging gently. If you're using a body cream, apply a sufficient amount to areas prone to dryness, such as the hands, feet, or even the lower legs due to potential hair removal.
