Mandelic acid, also known as mandelic acid (first extracted from bitter almond), is a large molecular weight fruit acid that can speed up the metabolism of skin cells, exfoliate, help reduce fine lines, and remove deposits on the stratum corneum. Melanin in cells, improves pigmentation, has a whitening effect (can be used to lighten acne marks). However, the effect is slightly inferior to that of glycolic acid, because mandelic acid has a large molecular weight and weak permeability. Because of this, mandelic acid is less irritating to the skin and is also suitable for sensitive skin. In addition, mandelic acid can inhibit the activity of Staphylococcus epidermidis, Candida albicans and other bacteria, as an antibacterial agent.