Niacin is a B vitamin. In large doses, it’s the most effective therapy for raising HDL cholesterol levels and thus is often prescribed for people who need to elevate their HDL values. Niacin can also lower triglyceride and LDL cholesterol levels. The drug is available in immediate-release and extended-release (Niaspan) versions. The extended-release version is also sold in combination with lovastatin (brand name: Advicor) and simvastatin (brand name: Simcor).

Niacin Benefits

Niacin produces increases in HDL cholesterol levels of up to 35 percent. The drug also reduces LDL cholesterol by 10 to 20 percent and triglycerides by 20 to 30 percent. When used alone, niacin decreases the risk of heart attacks and heart attack deaths. When combined with a bile acid sequestrant or a statin, niacin slows the progression of atherosclerosis and helps shrink plaques in the coronary arteries.

Niacin Side Effects

Skin flushing and itching are common side effects of niacin. These side effects are not dangerous and are more likely to occur with immediate-release than extended-release niacin and with higher dosages (more than 2 g a day).

More serious side effects include liver damage, ulcers in the stomach or upper intestine, gout, and increases in blood glucose levels. If you have a history of ulcers, liver disease, or gout, you should not take niacin. If you have diabetes or prediabetes, you will need to use niacin with caution, taking no more than 1 g a day. Because of the risk of these serious side effects, all types of niacin (even the preparations available over the counter) should be used under a doctor’s supervision.

Publication Review By: Roger S. Blumenthal, M.D. and Simeon Margolis, M.D., Ph.D.

Published: 08 Jul 2011

Last Modified: 15 Jan 2015