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By injection, hyaluronic acid is delivered directly to the dermis. However, in the skin, hyaluronic acid is present in high concentrations not only in the dermis, but also in the epidermis, where it plays a key role in the process of division and migration of keratinocytes (epidermal cells).
It is the characteristics of the hyaluronic acid of the epidermal layer that largely determine the ability of the skin to recover. Hyaluronic acid in the composition of a cosmetic product can affect the skin at two levels: high molecular weight remains on the surface of the skin, where it forms a protective moisturizing barrier, low molecular weight – penetrates into the deep layers of the epidermis, where it improves skin tone and elasticity and helps to smooth fine wrinkles with regular use.
MYTH: Hyaluronic acid is not effective at low concentrations.
Studies show that with a balanced product formula, even low concentrations of hyaluronic acid can provide the desired cosmetic effect. In addition, hyaluronic acid and its salts (for example, sodium hyaluronate, a form of high molecular weight hyaluronic acid) are distinguished by the ability to form high-viscosity aqueous solutions already at low concentrations, and at relatively high concentrations – pseudogels, solutions of colossal viscosity. Therefore, adding high concentrations of hyaluronic acid to a cosmetic product would make it impossible to apply, it would be very viscous and sticky.
MYTH: Hyaluronic acid “sucks” water out of the skin.
Hyaluronic acid is very hygroscopic, i.e. able to attract water. This property is used when adding its high-molecular forms to the composition of a cosmetic product, the main point of application of which is the skin surface. At the same time, having a large size of molecules that are not able to penetrate into the deep layers of the epidermis, as well as the dermis, hyaluronic acid, remaining on the surface of the skin, reduces the loss of moisture by the skin, attracting water to itself. Low molecular weight forms of hyaluronic acid have a slightly different mechanism of action – they retain water already in the epidermis, so water is fixed inside the skin and its excessive evaporation does not occur.