Water-soluble vitamins
Vitamin B3 (Niacin)
NAD+ precursor
NAD/NADP cofactors; energy metabolism, DNA repair.
Upper-limit caution
The Tolerable Upper Intake Level for Vitamin B3 (Niacin) is 35 mg per day. Routine intakes above this level — counting food + supplements — raise the risk of adverse effects. Multivitamins, fortified foods, and standalone supplements stack faster than people expect.
What Vitamin B3 (Niacin) does
Niacin is the precursor to NAD+ and NADP+ — the most heavily used redox cofactors in the cell. The body can synthesize a small amount of niacin from tryptophan (~1 mg per 60 mg tryptophan), so frank deficiency requires both low niacin and low protein. The upper limit of 35 mg/day applies to nicotinic acid only; high-dose nicotinic acid causes intense flushing (prostaglandin-mediated) and at gram-level cardiology doses can cause hepatotoxicity. Nicotinamide and inositol hexanicotinate do not flush.
Food sources of Vitamin B3 (Niacin)
Approximate Vitamin B3 (Niacin) content per serving. Whole-food intake counts toward your daily total alongside any supplemental dose.
| Food | Serving | Vitamin B3 (Niacin) |
|---|---|---|
| Cooked chicken breast | 3 oz | 10 mg |
| Cooked tuna | 3 oz | 9 mg |
| Cooked turkey breast | 3 oz | 10 mg |
| Peanuts | 1 oz | 4 mg |
| Brown rice (cooked) | 1 cup | 5 mg |
| Cooked salmon | 3 oz | 9 mg |
Signs of Vitamin B3 (Niacin) deficiency
- ●Pellagra's classic 'three Ds': dermatitis (sun-exposed areas), diarrhea, dementia
- ●Bright-red, painful tongue
- ●Apathy, depression, irritability
- ●Death in untreated severe pellagra
Who needs more Vitamin B3 (Niacin)
Groups and situations where Vitamin B3 (Niacin) requirements rise or status commonly runs low:
- ●Chronic alcohol use disorder
- ●Hartnup disease (impaired tryptophan absorption)
- ●Carcinoid syndrome — tryptophan diverted to serotonin synthesis
- ●Diets dominated by untreated maize without nixtamalization (historical pellagra cause)
How Vitamin B3 (Niacin) appears on labels
Supplement labels list Vitamin B3 (Niacin) under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your Vitamin B3 (Niacin) intake:
- niacin
- vitamin b3
- vitamin b-3
- nicotinic acid
- nicotinamide
- niacinamide
- inositol hexanicotinate
Best supplements for Vitamin B3 (Niacin)
Top-scoring supplements in our catalog that list Vitamin B3 (Niacin) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Deep dive
For mechanism of action, dosing protocols, evidence grade, and interaction warnings on Vitamin B3 (Niacin), see the full encyclopedia entry:
Niacin (Vitamin B3) encyclopedia entry →Guides covering Vitamin B3 (Niacin)
Long-form articles in our guide library that go deeper on Vitamin B3 (Niacin) — comparisons, protocols, and reviews.
Frequently asked questions
What is the daily target for Vitamin B3 (Niacin)?
What foods are highest in Vitamin B3 (Niacin)?
What is the best form of Vitamin B3 (Niacin) to supplement?
What are the signs of Vitamin B3 (Niacin) deficiency?
Who is most at risk for low Vitamin B3 (Niacin)?
Related water-soluble vitamins
Track your full intake
Formulate's free web app aggregates Vitamin B3 (Niacin) (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.
Track your intake free →Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.