Sugar is a natural source of glycolic acid, an alpha hydroxy acid (AHA) that penetrates the skin and breaks down the "glue" that bonds skin cells, encouraging cell turnover and generating fresher, younger-looking skin. Glycolic acid is typically used to treat sun-damaged and aging skin.
Sugar's small particles make an excellent topical exfoliant, and are used in a number of body scrubs to exfoliate dead surface skin cells and reveal the glowing, healthy-looking skin underneath. Sugar scrubs also have a few benefits over salt scrubs. For one, small sugar granules are generally gentler than salt, which can cause microscopic tears in the skin; two, because of sugar's natural properties, these scrubs are more hydrating than salt scrubs, which can strip skin of natural oils.