Niacin, also called nicotinic acid, is what is known as a B vitamin or Vitamin B3. It is an organic compound that does occur naturally in plants, animals, and it is added to foods as a vitamin supplement. Niacin can be used to both treat, as well as, prevent a lack of it in the human body. It is also used to lower cholesterol and triglycerides. It is even used to lessen the chance of a person having a heart attack who has high cholesterol and who may have had a heart attack before. Niacin can be used to treat the conditions already highlighted above. However, it can also be used to treat coronary artery disease atherosclerosis, and also for other purposes not listed here. Some Strengths that do go along with niacin are only available through a doctor's prescription.