What the research says

Research on the use of niacin you take by mouth to treat certain conditions shows:

• High cholesterol. Prescription niacin raises high-density lipoprotein (HDL) cholesterol. This is the "good" cholesterol that helps remove low-density lipoprotein (LDL), the "bad" cholesterol, from the blood. Even though niacin may raise HDL cholesterol, research suggests that niacin therapy isn't linked to lower rates of death, heart attack, or stroke.
• Niacin deficiency, also called pellagra. Niacin and a nutrient called niacinamide treat or prevent a lack of niacin. This condition isn't common in the United States.