Will Poly-γ-Glutamic Acid Replaces Hyaluronic Acid?

Tianjin,China--Sep.4,2025--Poly-γ-glutamic acid (abbreviated as PGA) is a water-soluble polyamino acid produced by microbial fermentation in nature. It is a unique anionic natural polymer formed through amide bonds between α-amino and γ-carboxyl groups. Specifically, PGA is a homopolypeptide composed of L- and D-glutamic acid units polymerized via γ-amide linkages, with a polymerization degree ranging between 1,000 and 15,000.

Since both PGA-producing strains and PGA itself are key components of natto (a traditional Japanese fermented food), its safety is unquestionable. Additionally, PGA has low viscosity and barely any sticky feel, giving it a competitive edge in the skincare-focused cosmetics industry.

Now, let’s briefly compare the main differences between HA and PGA.

First, HA is naturally present in the skin, while PGA is not (it is a natural peptide typically obtained through soybean fermentation).

Structurally, HA is an unbranched linear chain composed of repeating disaccharide units of D-glucuronic acid and N-acetyl-D-glucosamine. PGA, on the other hand, is a polymer derived from the amino acid L-glutamic acid. Essentially, based on their origins, HA is formed from polysaccharide chains, while PGA is formed through the polymerization of amino acids.

Now, let’s take a look at their respective efficacy mechanisms.

In terms of moisturizing effects, PGA’s unique three-dimensional structure allows it to create multiple layers of moisture retention and form a protective film on the skin’s surface, effectively preventing water evaporation. Hyaluronic acid, meanwhile, provides long-lasting hydration through its powerful water-absorption capacity.

Regarding anti-aging benefits, PGA helps delay skin aging through its antioxidant properties and by promoting skin barrier function. HA, on the other hand, directly improves skin laxity and wrinkles by stimulating collagen production.

In terms of safety, both PGA and HA perform excellently, as they are either naturally present in human skin or are edible components.

The widespread application of HA across various industries is well-recognized. Similarly, PGA—with its advantages such as biodegradability, biocompatibility, edibility, and non-toxicity—is already being used in fields including food processing, cosmetics, healthcare, water treatment, medical industries, and hydrogels.

In terms of synthesis methods, both hyaluronic acid and PGA can be produced through various approaches such as chemical synthesis and microbial fermentation. Chemical synthesis is less commonly used due to its complex processes, multiple steps, low yield, significant by-products, and involvement of toxic or hazardous gases in production.

Enzymatic conversion, suitable for PGA, avoids the drawbacks of chemical synthesis. However, the polymerization degree achieved through enzymatic conversion is low, resulting in a small molecular weight.

Microbial fermentation is currently the most commonly used and highly regarded method for producing both ingredients. It offers advantages such as mild culture conditions, controllable production processes, short production cycles, high yield, suitable molecular weight, high extraction efficiency, and environmental friendliness.

PGA is produced using specific microbial strains, such as certain Bacillus species, through fermentation processes. By screening strains and optimizing culture conditions, current yields can reach 10–40 g per liter of culture medium. HA, on the other hand, is produced using microorganisms like Streptococcus during fermentation.

So, will PGA replaces HA?

The answer, of course, is no. However, it can serve as an excellent complementary functional ingredient with promising prospects. According to data from Global Info Research, the PGA market is expected to reach $120.5 million by 2029, growing at a CAGR of 3.8% from 2022.

At a conference in Brazil, Bettina Gruber also presented test results of a facial toner containing PGA, which involved 60 participants, with efficacy evaluated by dermatology experts.

The results showed that after 14 days of use, the skin barrier was repaired, and wrinkles and fine lines were reduced. After 28 days, moisturizing effects became significant. Additionally, when exploring its antibacterial function, pores were noticeably reduced after 28 days of use, while colonization of Cutibacterium acnes decreased after 14 days. Therefore, she believes that further research into the bacterial-related functions of PGA is warranted.

The degradation of γ-PGA involves appropriately breaking down raw γ-PGA with a molecular weight of about 1,000 kDa to address its limited absorption and utilization by the skin. Experiments confirmed that 3% γ-PGA, heated at pH 2.0 and 80°C for 3 hours, or 3% γ-PGA, heated at pH 3.0 and 90°C for 1 hour, both yielded low-molecular-weight γ-PGA with a molecular weight of about 100 kDa, which exhibited optimal moisturizing performance.