What it is
Cholesterol (C27H46O, CAS 57-88-5) is the principal sterol of all animals and an essential structural component of animal cell membranes. In the skin it is one of the major lipids of the epidermal barrier, sitting alongside ceramides and free fatty acids in the spaces between corneocytes, where together they help limit transepidermal moisture loss. Because it is identical to a lipid the skin already makes, it is used in cosmetics as an emollient and skin-conditioning agent and can also help stabilize emulsions.
Safety & warnings
Cholesterol is a skin-identical lipid that is generally very well tolerated, including by people with sensitive or dry, barrier-compromised skin, and it is commonly paired with ceramides and fatty acids in barrier-repair formulas. Because cosmetic cholesterol is often derived from lanolin, those with a known lanolin sensitivity may wish to take note of the source.
Origin & sourcing
Cholesterol is biosynthesized by all animal cells and is distributed throughout body tissues, especially the brain, spinal cord, and animal fats and oils. Cosmetic cholesterol is typically obtained from animal sources such as lanolin (wool grease), and high-purity grades are also produced synthetically.
History
French chemist Francois Poulletier de la Salle first identified cholesterol in solid form within gallstones in 1769. In 1815 Michel Eugene Chevreul named it cholesterine, from the Ancient Greek words for bile and solid, and the modern -ol suffix reflects its classification as an alcohol.
Questions everyone asks
Is cholesterol in skincare the same as blood cholesterol?
Chemically it is the same molecule, but applying it to skin does not raise blood cholesterol; topically it acts as a barrier lipid and emollient.
Why is cholesterol added to sunscreen and moisturizers?
It is one of the skin's own barrier lipids, so it conditions and softens skin and helps reinforce the lipid matrix that holds in moisture.
Is cosmetic cholesterol vegan?
Usually not. It is an animal sterol and is commonly sourced from lanolin (wool grease), though synthetic grades exist.