Cholesterol

Cholesterol is a complex organic compound with the molecular formula C₂₇H₄₆O. It is a member of the biochemical family of compounds known as the lipids. Other lipids, such as the waxes, fats, and oils, share not a structural similarity (as is the case with most families of compounds), but a physical property-they are all insoluble in water, but are soluble in organic liquids.

Cholesterol belongs more specifically to a class of compounds known as the steroids. Most steroids are naturally occurring compounds that play critical roles in plant and animal physiology and biochemistry. Other steroids include sex hormones, certain vitamins, and adrenocorticoid hormones. All steroids share a common structural unit, a four-ring structure known as the perhydrocyclopentanophenanthrene ring system or, more simply, the steroid nucleus.