The smallest of the alpha-hydroxy acids, this odorless, colorless, and hygroscopic crystalline solid dissolves easily in water, and is used in numerous skin-care products. Glycolic acid derives from various sugar crops, as a glycolate (glycollate) is a salt or ester of glycolic acid. It is synthesized in a variety of ways, the but the primary means is a catalyzed reaction of formaldehyde with synthesis gas (carbonlyation of formaldehyde), as this is the most efficient and economical method of preparation. Industrially, glycolic acid is used for dyeing and tanning, and as a flavoring agent and preservative for food, as well as in pharmaceuticals as a skin care agent. Since its properties allow for excellent penetration of skin cells, glycolic acid is primarily used in skin care products such as skin peel formulas used professionally by dermatologists and in at-home kits for removing the top layers of the dermis due to acne scarring, hyperpigmentation, and improve many other skin conditions.