In part because it is added to white flour, most people generally get enough vitamin B3 from their diets to prevent a deficiency. However, 10–25 mg of the vitamin can be taken as part of a B-complex or multivitamin supplement. Larger amounts are used for the treatment of various health conditions.
The best food sources of vitamin B3 are peanuts, brewer’s yeast, fish, and meat. Some vitamin B3 is also found in whole grains.
Pellagra, the disease caused by a vitamin B3 deficiency, is rare in Western societies. Symptoms include loss of appetite, skin rash, diarrhea, mental changes, beefy tongue, and digestive and emotional disturbance.
Vitamin B3 occurs naturally in two forms: niacin (or nicotinic acid) and niacinamide (or nicotinamide). There are important differences between the forms when it comes to effectiveness and side effects. In very large doses (more than 3 grams a day), both forms may cause reversible hepatotoxicity (liver damage). However, niacinamide does not appear to have the other side effects associated with niacin, such as skin flushing, itching, and urticaria. Time-release niacin may reduce the risk of skin flushing, but such preparations raise even greater concerns about hepatotoxicity. Niacin improves serum lipid levels, whereas niacinamide does not. Niacinamide is used more often than niacin for conditions that respond to vitamin B3, because of its lower toxicity profile.1
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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.