Hyaluronic acid (hyaloid = glassy + uronic = acid) — a substance belonging to the group of polysaccharides, synthesized by cells of most living organisms, is an important component of the skin, muscles, nerves and other tissues.
In the descriptions of cosmetic formulations it is sometimes called «hyaluron», biochemists often use the phrase «Sodium hyaluronate», since it is present in the human body, mainly in the the form of sodium salt.
The biological role
Hyaluronic acid is essential for the formation of intercellular substance, which is a medium for cell functioning and their division, it proceeds to nutrient, and removal of waste products.
Half of the hyaluronic acid in the organism, is contained in the skin. Here it is a natural filler of intervals between the fibrous elements of the skin — collagen and elastin, is involved in their synthesis.
Hyaluronic acid is also involved in the processes of wound healing, effect on the immune responses, blocks the action of free radicals on cells, protecting tissues against premature aging.
One of the most important properties of hyaluronic acid is its highest hydrophilicity — the ability to bind moisture. One of its molecule is capable of holding up to 500 water molecules. Even a 1% aqueous solution of hyaluronic acid is not liquid and presents the viscous gel.
What causes a deficit of hyaluronic acid?
With age, under the influence of environmental factors and the natural aging process, the content of hyaluronic acid in the human body decreases. By the age of 50 its amount is reduced by half. Reducing the concentration of GA in the skin leads to its dehydration, a decrease in the synthesis of collagen and elastin, which is manifested in the form of dryness, sagging, wrinkles.
Application in Cosmetology
In modern cosmetology, hyaluronic acid injections are used as the primary method for moisturizing the skin. More effective agents for this purpose has not yet been found.
Since hyaluronic acid is not the extraneous agent to the body, preparations based on it are hypoallergenic.
Hyaluronic acid, used in cosmetics can be both natural and artificial origin. Because of its metabolism is very active (molecule GA «live» in the body for 2-3 days, then it collapses and the cell synthesizes the new one) to be inserted into the deeper layers of the skin, often used artificially synthesized substances, that differ in that the molecules are «stitched» together and their cleavage body requires more time.
In the composition for external use (creams, emulsions, lotions, etc.), the Hyaluronic acid acts as a humectant. The wafer-thin film on the surface of the skin, formed it, to prevent excessive evaporation of water and retains the necessary moisture. However, it does not clog pores, does not violate the transdermal gas exchange, it promotes deeper penetration of other active substances that make up the means. But applied to the surface of skin, hyaluronic acid does not penetrate into the deeper layers, it provides only superficial, transient hydration.
For deep and lasting hydration, for the introduction of hyaluronic acid in the deep layers of the skin is applied the biorevitalization method. биоревитализации.
The formulations with high concentration of hyaluronic acid, having a gel form, are used in contouring — for correction of nasolabial folds, wrinkles, lip augmentation.
In preparations for mesotherapy, the hyaluronic acid property is used to improve the penetration of the other substances into cells administered therewith.
Hyaluronic acid is used not only in cosmetics, it is part of the drugs that are widely used in many areas of medicine — ophthalmology, cardiology, transplantation, surgery and others.
In the late 80-ies of XX century, doctors have noticed that the healing process takes place during the prenatal period differently than after birth. For the treatment of congenital anomalies, surgical operations were carried out to the fetus, located inside the body of pregnant women(2-6 months pregnant). After the birth, on the bodies of these children no traces of the operations were found. Scientists attribute this to the very high concentration of hyaluronic acid in the body of the fetus and the amniotic fluid surrounding it.