Every living organism in the world contains hyaluronic acid as a structural component to their existence. Hyaluronic acid forms the basis of 90% of all dermal fillers used. As we age, or with certain disease conditions, fat and structural tissues in our bodies change in quantity. For example, fat over our temples reduces as we age. Or, in some cases, those seeking gender transitions may want to accentuate certain features to appear more feminine or masculine. Hyaluronic acid is degraded by an enzyme called hyaluronidase. Dermal fillers are placed under the skin to enhance features.