Polyglutamic acid is a recent introduction to the skincare sector. There have been more and more scientific studies on this ingredient, celebrating its excellent hydrating and regenerating properties. Let’s take a look at the main benefits of polyglutamic acid in skincare.
What are the benefits of polyglutamic acid for your skin?
- Polyglutamic acid for hydration
- Polyglutamic acid for reducing the appearance of wrinkles
- Polyglutamic acid vs certain skin conditions
Polyglutamic acid for hydration.
Polyglutamic acid or PGA is a hydrosoluble peptide from the polymerisation of glutamic acid extracted from the fermentation of soybeans. It helps to fight dehydration in several ways.
First, it forms a microscopic film, called a microgel, at the surface of the epidermis. This swells when it comes into contact with water, and captures H2O molecules. PGA is able to hold up to 5,000 times its weight in water. As a comparison, hyaluronic acid can hold up to 1,000 times its weight in water. A study from 2014 shows that PGA has a more hydrating effect than hyaluronic acid.
Next, PGA boosts the production of natural moisurising factor (NMF) molecules. As a reminder, in the stratum corneum, water is retained by hygroscopic substances that form during epidermal differentiation. Several studies have shown that polyglutamic acid can boost production of some of these molecules, including pyrrolidone carboxylic acid (PCA), lactic acid and urocanic acid.
Finally, PGA limits the effects of hyaluronidase, the enzyme responsible for the breakdown of hyaluronic acid in the skin. As a reminder, hyaluronic acid is a molecule that is primarily produced by fibroblasts in the dermis (the deepest layers of the skin), and which acts like a sponge to retain water. It helps to maintain the skin’s hydration and gives it that plumped, healthy look. As time goes by, our skin produces less, and of worse quality. At age 50, our stock of hyaluronic acid has reduced by half. This drastic drop leads to atrophy of the fatty pockets located deep in the dermis, causing fine lines and wrinkles on the surface of the skin. By inhibiting the activity of the enzyme hyaluronidase, polyglutamic acid prevents dehydration of the skin and the appearance of the signs of ageing.
Note: PGA helps to maximise skin hydration, but can’t penetrate deeply because of its high molecular weight. Its effectiveness is limited to the upper layers of the skin. Hyaluronic acid has a low molecular weight, so is highly recommended for deeply hydrating the skin.
Polyglutamic acid for reducing the appearance of wrinkles.
Skin ageing is due to intrinsic factors like a reduction in skin cell renewal, changes in the molecules which make up the dermis (hyaluronic acid, collagen), and the weakening of fatty and muscular tissue which starts to sag. Outside factors and lifestyle choices can accelerate the process (bad diet, smoking, excessive alcohol consumption, sun exposure, stress, lack of sleep…). Faced with these issues, the skin starts to wrinkle, it gets dryer, pigmentation marks can appear alongside dilated blood vessels. As the epidermis changes, it gets thicker or thinner depending on the person.
The first wrinkles that appear at around age thirty are usually dehydration wrinkles (generally around the eyes and/or on the forehead). Polyglutamic acid helps to slow this process thanks to its hydrating action, as above. Plus, a study has shown polyglutamic acid’s ability to more significantly strengthen the skin’s elasticity than collagen or hyaluronic acid when applied topically.
Polyglutamic acid vs certain skin conditions.
Traditionally, polyglutamic acid was used in medicine to accelerate healing of injuries and burns. A study from 2015, carried out on animals, showed that PGA could accelerate wound healing. It works by stimulating the synthesis of transforming growth factors TGF-β which play an essential role in the regulation of immune responses.
Also, polyglutamic acid is effective against acne bacteria S. aureus and Candida albicans yeast which causes fungal infections like athlete's foot, jock itch, nappy rash and fungal nail.
HONG-JOO SONA & al. In vitro evaluation of new functional properties of poly-γ-glutamic acid produced by Bacillus subtilis. Saudi Journal of Biological Sciences (2014).
MOON-HEE SUNG & al. Promotion effects of ultra-high molecular weight poly-γ-glutamic acid on wound healing. Journal of Microbiology and Biotechnology (2015).
RADECKA I. & al.Poly-γ-glutamic acid: production, properties and applications. Microbiology Society (2015).
HIURA N. & al. Characterization of poly(L-glutamic acid)-grafted hyaluronan as a novel candidate medicine and biomedical device for intra-articular injection. Journal of Biomedical Materials Research (2017).