How many Hyaluronic Acid does your skin have

Hyaluronic Acid  is a natural substance that constitutes a human body.
In contrast to 20~30, the content of hyaluronic acid in 30~40 was 75%, only 40 over the age of 60% years.
In the process of skin aging, the human body can reduce the hyaluronic acid, and decrease the skin elasticity.
So we need the vital injector to inject hyaluronic acid to fical skin to keep younger.