Hyaluronic acid (also called Hyaluronan or hyaluronate or HA) is a linear polysaccharide with repeating disaccharide units composed of D-glucuronic acid and N-acetyl glucosamine. Hyaluronic acid is a naturally occurring biopolymer whose molecular structure is highly conserved between mammalian species.

Hyaluronic acid is distributed widely throughout connective, epithelial, and neural tissues. First described in 1934, it has since been used across a wide variety of medical fields as diverse as neurosurgery and cutaneous wound healing.
Hyaluronic acid is one of the main lubricating components of synovial joint fluid, and it has been shown to increase the viscosity of the fluid. Hyaluronic acid is also an important component of cartilage. HA-based products developed for osteoarthritis (called "viscosupplementation") aid in pain relief, as well as lubrication and cushioning of the joint.

The average 70 kg (154 lbs) person has roughly 15 grams of hyaluronan in the body, one-third of which is turned over (degraded and synthesized) every day. Skin contains large amount of hy-aluronic acid which amounts to about 1/3 of total hyaluronic acid existing in live body. The highest hyaluronic acid content in the body, for people, occurs in the embryonic period, and it gradually decreases after birth. Age, as well as exposure to the sun and pollution, leads to decreased pro-duction of hyaluronic acid, resulting in decr-eased volume and the appearance of wrinkles. If the relative content of hyaluronic acid in the 20-year-old human body is positioned to 100%, it will drop to 65%, 45%, 25% respectively at the age of 30, 50, and 60 years old.
Hyaluronic acid is often used in formulation of skin care products, such as facial lotion, cream, because of its excellent moisture retention property. Hyaluronic acid ranges in size from 0.20×10⁶-2.50×10⁶ Da. Hyaluronic acid with different molecular weights has different functions in cosmetics.
 

 
Liyoung offers Hyaluronic acid through over 10 years' research and development. Now Liyoung can offer Hyaluronic acid for Cosmetic Grade, Food Grade, Eye Drop Grade and Pharma Grade.