The Hyaluronic acid in the skin begins to diminish as soon as you reach your twenties !. At the age of 30 it becomes more evident and noticeable . And by the time you reach 50 , the level of hyaluronic acid under your skin is reduced to half ! . Therefore , it is advisable to start applying skin care products with hyaluronic acid in the twenties itself so that the skin adapts to the adverse effects of ageing.