Vitamin B3 (niacin)
Nicotinic acid and nicotinamide
Vitamins. Modern nutrition.
Also called Niacin, Nicotinamide, Niacinamide, Vitamin PP
Pinyin: wéishēngsù B3
Spanish: Niacina
Liver harm at high dosesA B vitamin the body needs to make energy and to keep skin, nerves and the gut working well.
Did you know? The name niacin was chosen so it would not be confused with nicotine, the chemical in tobacco. Pellagra, the disease caused by too little niacin, once killed many poor people in the American South.
What it may help, and how strong the proof is
- Cholesterol. High-dose prescription niacin, often 1 to 2 grams a day, raises HDL (good cholesterol) and lowers LDL (bad cholesterol) and triglycerides in many trials. It causes flushing and can harm the liver.Good proof
- Skin. In one trial of adults at high risk, 500 mg of nicotinamide (a form of B3) twice a day led to fewer new non-melanoma skin cancers. That is one trial, so more research is needed. Niacin pills for other skin problems are not proven.Early proof
- Heart health. Large trials of niacin pills added to statin drugs, including AIM-HIGH and HPS2-THRIVE, did not lower heart attacks or strokes. Niacin is not a proven heart protector.Not supported
Parts of the body
Traditional use
In Mesoamerica, cooks soaked corn in lime, a process that frees niacin from the grain and protects people from pellagra. Corn-heavy diets without this step caused pellagra in the American South.
How it is classified
- Herbal actions
- Nutritive, Circulatory. Energy: neutral.
How people take it
Adults need 16 mg NE a day (men) or 14 mg NE a day (women). NE means niacin equivalents. The upper limit is 35 mg a day from pills and fortified foods, to prevent flushing and liver harm. Cholesterol doses are much higher and must be set and watched by a doctor.
Food, capsule and tablet.
Where to get it
Good sources are chicken breast, turkey, tuna, salmon, beef liver, peanuts, brown rice, mushrooms such as portobello, fortified cereals, and whole grains. The body can also make some niacin from the protein tryptophan, found in eggs, milk and meat. Pills come as niacin (nicotinic acid), which causes flushing, or as niacinamide, which does not.
Be careful
Niacin (nicotinic acid) causes flushing, itching and a hot red face within an hour of a dose. Long-term high doses can harm the liver, raise blood sugar, and cause stomach upset or gout. Niacinamide does not flush, but high doses can still harm the liver.
Avoid if: liver disease; stomach ulcers; gout; diabetes.
Mixing with other things
- Works well together
Riboflavin and niacin are both needed for enzymes that make energy in cells.
- Use cautionStatins (Lipitor, Zocor, Crestor)
Niacin with a statin raises the risk of muscle damage. Big trials also did not show added heart benefit.
- Use cautionBlood pressure medicine (lisinopril, amlodipine, losartan)
Niacin can lower blood pressure, which may add to blood pressure medicines.
- Use cautionDiabetes medicine (metformin, insulin, glipizide, Ozempic)
Niacin can raise blood sugar, which works against diabetes medicines.
- Use cautionAlcohol (beer, wine, spirits)
Alcohol adds to the liver risk of high-dose niacin.
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The honest take
Niacin is needed, and true pellagra is now rare where diets are varied. Prescription niacin can change cholesterol numbers, but big trials did not show fewer heart attacks. Doses that change cholesterol can harm the liver, so they should only be used with a doctor.