Learn more about lipids with Professor Thomas M. Terry. Fats or triglycerides are formed by three fatty acids each bonded by an ester linkage to glycerol. 1  Twist and turn the lipid below to see how kinky fatty acids are.
Superficial peels are the mildest type of chemical peel. They can be used on all skin types. In most cases, they use liquid containing a mild (dilute) acid, most often glycolic acid. Dry ice (solid carbon dioxide) is sometimes used. Medium peels soak deeper into the skin than superficial peels do.
By definition, superficial chemical peels do not enter the dermis or the lower layers of the epidermis. The two major acids that are used for this purpose are glycolic acid and salicylic acid. Glycolic acid is a water-soluble alphahydroxy acid of small molecular weight that rapidly penetrates into the skin.