Hyaluronic acid is a kind of substance in the basal layer of human skin. After filling and injecting into the skin, it will be absorbed and decomposed by the human body continuously, but it has no toxic side effects on the human body, so it is one of the safest cosmetic fillers at present. In the medical consensus, filler in the human body, the shorter the residence time in the body, the safer for human health, and with age, the human body’s muscle and skin direction will also change, if the residence time is too long, it is easy to cause filler and after the muscle structure is not harmonious, so as to affect the aesthetics. According to the molecular weight of hyaluronic acid and the different physique of the aesthetics, the maintenance time of hyaluronic acid in the human body is different. The hyaluronic acid with larger molecular weight, which is usually used for injecting the nose bridge, apple muscle or temporal area, maintains about 8-12 months, and can keep the best shape in half a year. On the other hand, hyaluronic acid with smaller molecular weight is usually used for injection of silkworms or tear trough, which is usually absorbed within six months, and the best form can usually be maintained for about three months. When injecting hyaluronic acid, lovers need to go to regular hospitals, and experienced doctors will choose the suitable hyaluronic acid for injection. In addition, the maintenance time of hyaluronic acid is related to post-operative care, if you do a good job of post-operative care, the maintenance time will be longer.