What is Cholesterol?

Cholesterol is a waxy, fat-like compound that belongs to a class of molecules called steroids. It's found in many foods, in your bloodstream and in all your body's cells. If you had a handful of cholesterol, it might feel like a soft, melted candle. Cholesterol is essential for:

  • Formation and maintenance of cell membranes (helps the cell to resist changes in temperature and protects and insulates nerve fibers)
  • Formation of sex hormones (progesterone, testosterone, estradiol, cortisol)
  • Production of bile salts, which help to digest food
  • Conversion into vitamin D in the skin when exposed to sunlight.

The formation of cholesterol involves a series of complicated biochemical reactions that begin with the widespread 2-carbon molecule Acetyl CoA: Acetyl CoA (C2) --> mevalonate (C6) --> isopentenyl pyrophosphate (C5) --> squalene (C30) --> cholesterol (C27). Cholesterol is made primarily in your liver (about 1,000 milligrams a day), but it is also created by cells lining the small intestine and by individual cells in the body.


Most of the body's cholesterol is manufactured in the liver.