Niacin (B3)

Water-soluble · energy

What does Niacin (B3) do in your body?

Becomes NAD and NADP — coenzymes used in more than 400 reactions.

What does Niacin (B3) do?

NAD and NADP carry electrons in energy production and help repair DNA.

Where does Niacin (B3) act in the body?

Every cell.

Which foods contain Niacin (B3)?

Poultry, fish, meat, peanuts, brown rice, fortified grains. The body can also make some from the amino acid tryptophan.

How much Niacin (B3) do adults need?

RDA: 16 mg NE (men), 14 mg NE (women). Upper limit: 35 mg/day from supplements and fortified foods.

What happens with too little Niacin (B3)?

Severe deficiency causes pellagra: dermatitis, diarrhea and dementia.

Can you get too much Niacin (B3)?

Supplemental nicotinic acid causes flushing; high doses can harm the liver.

What does Niacin (B3) interact with?

Niacinamide in skincare is the same vitamin, used topically.

What is known and unknown about Niacin (B3)?

Roles are established. High-dose niacin for cholesterol did not reduce heart events in major trials when added to statins.

Evidence & sources

• The adult RDA for niacin is 16 mg NE (men) and 14 mg NE (women); the UL is 35 mg. Evidence: regulatory. Known: Set by the Institute of Medicine (1998). Unknown: — Source: NIH Office of Dietary Supplements, Niacin — Health Professional Fact Sheet (Current revision).

Connected topics

• Energy Metabolism
• Chicken
• Riboflavin (B2)
• Liver

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General education only, not medical advice. Drafted Oct 2026 · pending qualified expert review.