Hyaluronic acid (scientific name hyaluronic acid) is a natural substance existing in human body and widely distributed in connective tissues of eyes, bones, joints and skin. Hyaluronic acid is a carbohydrate, and human body functions are naturally generated. There is about 15g hyaluronic acid in 70kg human body, of which 50% hyaluronic acid exists in skin and fascia, and one third of hyaluronic acid is metabolically updated every day. The most fundamental reason why the human body is aging is that its ability to produce hyaluronic acid begins to decline. At the age of 40, it is only 50% of normal, and at the age of 60, it is only 10%. One of the culprits of skin aging is that the human body gradually loses its ability to produce hyaluronic acid with age. Many women envy those female stars in their forties and fifties. Their skin is still as full, moist and elastic as a girl in her early twenties, as if time had stopped on them. In fact, the secret of their frozen age is to supplement hyaluronic acid!