Vitamin B3 / niacin / nicotinamide

Also known as niacinamide, nicotinic acid, vitamin b-3, niacine.

Last reviewed October 9, 2026 · Jump to references

What is Vitamin B3 / niacin / nicotinamide?

In plain words

Vitamin B3 is a nutrient found in foods and supplements, commonly as niacin or nicotinamide. The body turns it into helpers that release energy from food and support cell maintenance and repair. Researchers study these forms for their effects on blood fats and skin health, but the two forms do not have identical effects. Their role in preventing B3 deficiency is well established, while high amounts can cause harm, including liver injury.

Technical definition

Vitamin B3 comprises the water-soluble vitamers nicotinic acid (niacin) and nicotinamide (niacinamide), structurally related pyridine derivatives obtained from food; the body can also produce niacin equivalents from tryptophan. Both serve as precursors to NAD and NADP, coenzymes involved in energy metabolism and cellular maintenance, while nicotinic acid—but not nicotinamide—activates the HCAR2 receptor. Both forms are available in dietary supplements, and certain nicotinic acid formulations are approved prescription drugs in the United States for lipid disorders.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.