Quick answer
Men need 16 mg NE of niacin a day and women 14 mg NE, counting food and supplements together, and most adults get that from diet alone. The upper limit for niacin from supplements is 35 mg a day. Prescription doses of 500 to 2,000 mg are a medicine, used only under a doctor's care.1,2,3
Key facts
- Pregnancy raises the recommended amount to 18 mg NE a day, and breastfeeding to 17 mg NE.1
- One mg NE equals 1 mg of niacin or 60 mg of tryptophan, so the protein you eat counts toward the total.2
- Nicotinic acid can cause flushing from about 30 mg, which is below the 35 mg limit.1,2
- Supplement users take in two to three times as much niacin as they would from diet alone.2
Recommended amounts by age
| Age | Recommended amount | Upper limit from supplements |
|---|---|---|
| Birth to 6 months | 2 mg | Not set |
| 7 to 12 months | 4 mg NE | Not set |
| 1 to 3 years | 6 mg NE | 10 mg |
| 4 to 8 years | 8 mg NE | 15 mg |
| 9 to 13 years | 12 mg NE | 20 mg |
| Boys 14 to 18 | 16 mg NE | 30 mg |
| Girls 14 to 18 | 14 mg NE | 30 mg |
| Men 19 and over | 16 mg NE | 35 mg |
| Women 19 and over | 14 mg NE | 35 mg |
| Pregnant | 18 mg NE | 35 mg (30 mg under 19) |
| Breastfeeding | 17 mg NE | 35 mg (30 mg under 19) |
For babies, NIH says breast milk, formula and food should be the only sources of niacin, and no upper limit is set for them.2
What mg NE means
Niacin amounts are given in mg of niacin equivalents (NE). One mg NE is 1 mg of niacin or 60 mg of tryptophan.1,2
On a Supplement Facts panel, mg NE is simply the niacin in the product. The unit matters more for food, where tryptophan from protein adds to the niacin itself, although how much each person converts varies.2
How much you already get
US men take in about 31.4 mg of niacin a day from food and drink and women about 21.3 mg. Only about 1% of adults fall below the average requirement.2
About 21% of people in the US take a supplement with niacin, rising to about 40% of adults aged 60 and over. Supplements double or triple total intake, and in one national survey about 10% of supplement users reached or passed the upper limit.2
That is why the upper limit, not the recommended amount, is the number to watch when you add a supplement. It counts only niacin from supplements and medicines, so add up every label you take.2
Why the limit is 35 mg
The upper limit for niacin from supplements and medicines is 35 mg a day for adults, including during pregnancy and breastfeeding. It is 30 mg for ages 14 to 18, 20 mg at 9 to 13, 15 mg at 4 to 8 and 10 mg at 1 to 3. It is set at the level linked to flushing, covers both nicotinic acid and nicotinamide, does not count niacin in food, and does not apply to people taking niacin under medical supervision.1,2
The limit was set at the amount linked to skin flushing. It covers nicotinamide as well: although nicotinamide does not flush, the board that set the limit judged that a limit based on flushing would also guard against nicotinamide's own side effects at high doses.2
When the amount becomes a medicine
Prescription niacin tablets hold 500 or 1,000 mg of extended-release nicotinic acid, and the label's daily doses run from 500 to 2,000 mg, taken only under a doctor's care.3
At 1,000 mg a day or more, nicotinic acid can cause low blood pressure that makes falls more likely, extreme tiredness, high blood sugar, nausea, heartburn, stomach pain, and blurred vision or fluid buildup in the eye.1,2
US heart societies advise checking liver enzymes, blood sugar and uric acid before high-dose nicotinic acid is started, while the dose is raised, and every 6 months after. A niacin-only supplement of 500 mg or more delivers a medicine dose without those checks.2
What's in ours
What’s in ours
- Men's Multi: Niacin, 30 mg NE per serving, from the label
Questions people ask
Is 500 mg of niacin too much?
As a supplement, yes. It is more than 14 times the 35 mg upper limit and sits in the prescription range, where liver harm and other serious side effects become a concern. Take that amount only if a doctor prescribes it and monitors you.2,3
Does niacin from food count toward the 35 mg limit?
No. The limit applies only to niacin from supplements and medicines, and niacin that occurs naturally in food has not been reported to cause harm.2
How much niacin do men need compared with women?
Men need 16 mg NE a day and women 14 mg NE. The upper limit from supplements is the same for both, 35 mg a day.1
How much niacin does a child need?
From 6 mg NE a day at ages 1 to 3 to 12 mg NE at 9 to 13. Children's upper limits are lower than adults', from 10 mg at 1 to 3 to 20 mg at 9 to 13, so check any product against the child's limit.1
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Sources
- National Institutes of Health, Office of Dietary Supplements. Niacin: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-07.
- National Institutes of Health, Office of Dietary Supplements. Niacin: Fact Sheet for Health Professionals. Updated November 18, 2022. Opened 2026-10-07.
- Niacin extended-release tablets: prescribing information and patient information (Amneal Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published September 18, 2026. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.