Cholesterol is a waxy substance found in the blood and is an essential component of cell membranes. It is also involved in the production of hormones and vitamin D. There are LDL (low-density lipoprotein) and HDL (high-density lipoprotein). LDL is often referred to as the “bad” cholesterol because it can build up in the arteries, leading to blockages and increasing the risk of heart disease. On the other hand, HDL is known as the “good” cholesterol because it helps remove excess cholesterol from the body.