Niacin (Vitamin B3)
Also known as Vitamin B3, Nicotinic acid, Nicotinamide, Niacinamide
Niacin is a water-soluble B vitamin essential for turning food into energy. Requirements are expressed in milligrams of niacin equivalents (mg NE) because the body can also make niacin from the amino acid tryptophan.
The recommended intake sits at about 46% of the level considered the safe daily ceiling, leaving comfortable headroom.
Why it matters
What it does in your body
- Energy metabolism
- Coenzyme (as NAD and NADP) in more than 400 enzyme reactions
- DNA repair and cell signaling
- Skin, nerve, and digestive health
- Cholesterol handling (at pharmacologic doses)
By age, sex, and life stage
How much you need
Values are in mg NE (niacin equivalents); 1 mg NE equals 1 mg niacin or 60 mg of dietary tryptophan. Values are RDAs except for infants, which are Adequate Intakes (AI).
Recommended intake across life
in mg NE/dayBars scale to the highest recommendation shown. Where men and women differ, both values are listed.
Full reference table
| Life stage | Male | Female |
|---|---|---|
| Infants 0-6 mo | 2 (AI) | 2 (AI) |
| Infants 7-12 mo | 4 (AI) | 4 (AI) |
| Children 1-3 | 6 | 6 |
| Children 4-8 | 8 | 8 |
| Children 9-13 | 12 | 12 |
| Teens 14-18 | 16 | 14 |
| Adults 19+ | 16 | 14 |
| Pregnancy | n/a | 18 |
| Lactation | n/a | 17 |
Values in mg NE/day. AI marks an Adequate Intake, used when there is not enough evidence for a formal recommendation.
What moves the number
What changes your needs
Age
Needs rise from 6 mg NE/day in early childhood to 16 mg NE/day (men) and 14 mg NE/day (women) in adulthood.
Sex
Adult men need 16 mg NE/day and adult women need 14 mg NE/day.
Body weight / size
Because niacin supports energy metabolism, needs scale modestly with body size.
Pregnancy and lactation
Pregnancy raises the need to 18 mg NE/day and lactation to 17 mg NE/day.
Tryptophan intake
The body can convert dietary tryptophan into niacin (60 mg tryptophan yields 1 mg NE), so a protein-rich diet contributes to niacin status.
Running low
Signs you might not get enough
Most at risk: People with undernutrition or very limited diets, those with low intake of riboflavin, vitamin B6, or iron, and people with Hartnup disease or carcinoid syndrome.
Too much
Can you get too much?
Adverse effects come from supplements and fortified foods, not from niacin naturally in foods. Flushing is the most common early effect; sustained very high doses used to treat cholesterol can harm the liver and should only be taken under medical supervision.
Where to get it
Best food sources
The bottom line
Poultry, fish, meat, peanuts, and enriched grains supply ample niacin, and the body also makes it from tryptophan. Adults need 14 to 16 mg NE/day; keep supplemental and fortified niacin under 35 mg/day unless a doctor advises otherwise.
Track niacin (vitamin b3) automatically
Niacin (Vitamin B3) is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The recommended intakes, upper limits, and food-source amounts on this page come from the primary references below. Numbers were checked against the current NIH Office of Dietary Supplements fact sheets and the Institute of Medicine (now the National Academies) Dietary Reference Intakes.
- NIH Office of Dietary Supplements, Niacin Fact Sheet for Health Professionals
- Institute of Medicine (IOM/NASEM), Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998)
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.