Malic acid is likely effective for treating dry skin and sun damage, according to WebMD. It works by getting rid of the top layers of dead skin cells. The acid also helps to improve the thickness of the deeper skin layers, enhancing skin firmness.
Also known as alpha hydroxy acid, malic acid is a group of natural acids available in foods, notes WebMD. Some people take malic acid together with magnesium to treat tenderness and pain caused by fibromyalgia. It is also applied to the skin to treat acne and enhance the appearance of acne scars. Malic acid is also an ingredient in many cosmetic products.