Cholesterol is a relatively small molecule, which means it can diffuse easily throughout the body and get into cells. The average adult has about 300 grams of cholesterol in their body. Cholesterol circulates in the blood as part of the body’s cells and helps them function. It is made in a cell’s mitochondria while aerobic respiration occurs. When produced in sufficient quantities, cholesterol helps keep membranes intact and nerves active; when produced in too much quantity (hypercholesterolemia), it may be deposited into fatty plaques on artery walls (atherosclerosis). This deposition may lead to atherosclerosis, which can cause heart problems or kill you through clogging arteries or heart attacks.
Cholesterol is also used to make several hormones, including:
testosterone (important for sex drive in men)
cortisol (important for stress response)
progesterone (important for pregnancy)