What other active ingredients can polyglutamic acid be combined with?

Polyglutamic acid is a peptide with moisturizing properties derived from the fermentation of soybeans, further, a traditional Japanese food called "Nattô". Applied on the surface of the skin, it forms a microscopic film called microgel. It swells and traps water, promoting its retention. Polyglutamic acid is therefore capable of retaining up to 5,000 times its weight in water, five times more than the hyaluronic acid to which it is often compared. It also reduces the production of hyaluronidase, the enzyme responsible for the degradation of hyaluronic acid present in dermal and epidermal skin. By reducing its synthesis, polyglutamic acid prevents dehydration of the skin and therefore the appearance of wrinkles or fine lines.

In a cosmetic formula, polyglutamic acid is generally introduced at a percentage between 0.1 and 3%. It is advisable not to exceed these concentrations because an overdose of polyglutamic acid can weaken the skin and cause redness. Its pure use is therefore not recommended. This acid is referenced under the INCI (International Nomenclature Cosmetic Ingredient) name "Polyglutamic Acid" and is defined as a skin care ingredient.

With its high molecular weight, polyglutamic acid acts only on the surface layers of the skin. To benefit from a more in-depth effect on hydration and wrinkle reduction, it is relevant to combine polyglutamic acid products with the following compounds:

• Hyaluronic acid.

Hyaluronic acid and polyglutamic acid are complementary. They both optimize the skin's hydration. They differ mainly in their origin: hyaluronic acid is naturally present in the body (mainly in the skin), while polyglutamic acid is not. Their chemical structure and molecular weight are also different. Hyaluronic acid reaches deeper into the skin because its molecular weight is lower. Hyaluronic acid acts on the internal cells of the dermis for long-lasting hydration and contributes to the oxygenation, toning and nutrition of the skin. On the other hand, polyglutamic acid will form a protective film on the surface of the corneal layer, preventing water evaporation. During your beauty routine, morning and evening, you can for example apply first the hydrating serum with hyaluronic acid, then the plumping polyglutamic acid serum with red algae extract.

• Retinol.

Retinol (or vitamin A) is the ultimate anti-aging skin care ingredient. It acts on several levels. It stimulates the production of collagen and elastin for smoother, more elastic skin. Moreover, it is recognized for its antioxidant virtues, which prevent premature aging of skin cells. It also has an effect on the production of melanin in the skin, helping to reduce the appearance of brown spots that can appear with age. Polyglutamic acid can provide a complementary benefit to retinol, by limiting the degradation of hyaluronic acid. The combination of retinol and polyglutamic acid can therefore effectively fight against the signs of aging. During your beauty routine, morning and evening, you can first apply the polyglutamic acid serum with red algae extract and then the firming face cream with 0.2% retinol and tsubaki oil.

Note: People with sensitive skin should avoid combining several acids. For instance, polyglutamic acid combined with certain active ingredients such as glycolic acid, salicylic acid or lactic acid is not recommended.