Among the functions attributed to sebum in humans are the protection of the skin from UV rays, the inhibition of harmful microorganisms on the skin, the delivery of antioxidants to the skin surface and the creation of a moisture barrier to prevent excess water from passing through the skin. Though it performs many functions, science does not yet have a complete understanding of the role of sebum in the body.
Scientists do know that the production and secretion of sebum is the principal activity of mature sebaceous glands. The secreted sebum is a complex mixture of lipids consisting of 57.5 percent triglycerides and fatty acids, 26 percent wax esters, 12 percent squalene, and 4.5 percent cholesterol and esters. The squalene and wax esters secreted by the sebaceous glands are unique to sebum and not found anywhere else in the body. They are the major components that supply the skin with protection. Despite its benefits, the oily quality of sebum can cause hair follicles to become clogged if it is produced in excess. This can result in acne, whiteheads, blackheads or, in a worst case scenario, the follicle wall can break down, allowing sebum to leak into the tissue and forms pustules.