Hyaluronic acid stock solution is a kind of hyaluronic acid (HYALURONIC ACID, referred to as HA), also known as uronic acid. Natural hyaluronic acid is a polymer polysaccharide. It is a linear polymer polysaccharide composed of glucuronic acid-N-acetate glucosamine as disaccharide molecular units. Hyaluronic acid, according to the injection doctor at Hangzhou Victoria Medical Beauty Hospital, was originally used as glue. It exists in the dermal tissue of human skin and is responsible for storing water and increasing skin volume, making the skin look plump, plump and elastic. However, hyaluronic acid will disappear with age, causing the skin to lose its ability to store water, gradually becoming dull, aging, and forming fine wrinkles.