Lipids could be considered the most important part of skin care products. They are able to protect the skin from water loss, helping the barrier function of the skin. Lipids are defined by their ability to be soluble in organic solvents. In general lipids are used by mammals like us for energy reserves and to form cell membranes. The main lipid category is a triglyceride, also called a triacylglycerol. Other lipids include phospholipids, steroids and essential oils (for lack of any other category to put them). We’ll focus on the triglycerides alone though.
The structure of a triglyceride is a glycerol molecule as a backbone with three fatty acids attached to that. Since glycerol is a three carbon sugar, each fatty acid can bond to one of the carbons. Glycerine is also an alcohol as defined by the –OH groups.