50 % of hyaluronic acid in our body is found in the skin. Hyaluronic acid can absorb liquid in a volume 1000 times larger than its own, thus acting as an excellent "sponge" under the skin. There are about 15 grams of hyaluronic acid in a 70 kilogram body.

IMPACT:

• filling wrinkles and facial expression lines
• volume increase (lips, cheekbones)

Functions of hyaluronic acid in the skin:

• it is a structural component of the extracellular matrix
• stimulation of the production of collagen, elastin and endogenous hyaluronan
• regulating the diffusion of water, electrolytes, and nutrients
• skin filler
• high water binding capacity

METABOLISM - reduction of hyaluronic acid in the skin:

• oxidation by hydroxylation of glucuronic acid
• enzymatically via hyaluronidase

Hyaluronic acid is a polysaccharide (made up of sugar molecules): D-glucuronic acid and N-acetyl-D-Glucosamine.

Chemical structure of hyaluronic acid (GAG)

GAG or glycosaminoglycan is a general name for a number of similar molecules found in the plant and animal world and which have the function of creating tissue structure. Examples of GAG molecules are cellulose in the plant world and chitin in the animal world. Hyaluronic acid is polysaccharide with a repeating unit disaccharides which contains D-glucuronic acid and N-acetyl glucosamine with ß-(1-3) protein-binding compounds. Each polysaccharide unit is cross-linked with ß-(1-4) compounds. Hyaluronic acid has a molecular weight between 5,000 and 20,000,000 Daltons. Hyaluronic acid derived from synovial fluid has a molecular weight of approx. 3,500,000 Daltons.

Molecular weight – Determines the viscosity and strength of the product at a certain concentration of hyaluronic acid. The higher molecular weight means that the product can have a lower concentration of hyaluronic acid and still maintain the same level of viscosity.

Viscosity – Describes the "density" of the product. A higher viscosity means that the product is thicker and has more stability inside the skin.

Modulus of elasticity (G') – Describes the tendency of a substance to elastically (non-permanently) deform when a force is applied to it. A higher modulus of elasticity means that the product is more suitable for deep lines.

Shear Stress – Describes how easily a product changes from a solid to a liquid state. The high shear stress factor will allow the product to easily change when absorbed into the skin and to regain its shape once inside the skin.