Glycerol

Glycerol has a carbon skeleton of three carbon atoms with three alcohol groups attached to the carbons. At room temperature is has the appearance of a clear lightweight oil and is commonly used under the name glycerin. It is an ingredient of many cosmetics to make them smooth and easy to spread. It is helpful as a moisturizer for the skin.

Replacement of the three hydrogens on the alcohol groups with three fatty acid molecules creates a molecule of a lipid, an important class of molecules for biochemistry.