Hyaluronic acid is a natural building block found in human cell tissue, including the skin. Chemically, physically and biologically, hyaluronic acid is identical in the tissues of all living beings. An allergy test is not required! It is injected into the tissue to provide the intercellular spaces of the connective tissue with a space-filling viscoelastic additive. Introducing this material into skin tissue can correct skin deformities caused by wrinkles or sunken scars.​