By the Nutriveda editorial team · Updated 5 November 2026
Vitamin B3 (niacin) is the name for two water-soluble compounds, nicotinic acid and nicotinamide, which the body turns into NAD and NADP, coenzymes needed by more than 400 enzymes, above all for releasing energy from food. EFSA sets a population reference intake of 1.6 mg niacin equivalents (NE) per megajoule, about 13 mg NE a day on 2,000 kcal. Meat, poultry, fish, peanuts, mushrooms and whole grains supply niacin, and the body also makes some from the amino acid tryptophan in protein foods. In supplements the form matters: nicotinic acid causes flushing at low doses, and EFSA’s upper limits for the two forms are very different.
What vitamin B3 does
NAD and NADP take part in energy metabolism and in hundreds of other reactions in cells (NIH). The body can make niacin from tryptophan: about 60 mg of tryptophan yields 1 mg of niacin, counted as 1 mg niacin equivalent (EFSA). This conversion needs riboflavin, vitamin B6 and iron, so a shortage of those can lower niacin status too (NIH). The EU allows these health claims for foods that are at least a source of niacin (Regulation (EU) 432/2012):
- “Niacin contributes to normal energy-yielding metabolism”
- “Niacin contributes to normal functioning of the nervous system”
- “Niacin contributes to normal psychological function”
- “Niacin contributes to the maintenance of normal mucous membranes”
- “Niacin contributes to the maintenance of normal skin”
- “Niacin contributes to the reduction of tiredness and fatigue”
How much you need a day
| Group | EFSA population reference intake | For reference: NIH RDA (US) |
|---|---|---|
| Men, 18+ | 1.6 mg NE/MJ | 16 mg NE |
| Women, 18+ | 1.6 mg NE/MJ | 14 mg NE |
| Pregnancy | 1.6 mg NE/MJ | 18 mg NE |
| Breastfeeding | 1.6 mg NE/MJ | 17 mg NE |
| Children from 7 months | 1.6 mg NE/MJ | – |
| Upper limit (UL), adults, nicotinic acid | 10 mg | 35 mg (supplemental niacin) |
| Upper limit (UL), adults, nicotinamide | 900 mg | 35 mg (supplemental niacin) |
EFSA’s value is 6.6 mg NE per 1,000 kcal, so about 13.2 mg NE on 2,000 kcal and 16.5 mg NE on 2,500 kcal (our calculation). The same value per MJ applies to children, pregnancy and breastfeeding. The upper limits for the two forms come from the EU Scientific Committee on Food (2002) and are listed in EFSA’s overview; nicotinamide is tolerated at far higher doses than nicotinic acid. The US limit of 35 mg applies only to supplemental niacin; no adverse effects have been reported from niacin naturally present in food (NIH). The NHS says 17 mg or less of nicotinic acid, or 500 mg or less of nicotinamide, a day from supplements is unlikely to cause harm.
Best food sources
| Food | Niacin, 100 g | Portion | Per portion |
|---|---|---|---|
| Beef liver, pan-fried | 17.5 mg | 85 g | 14.9 mg |
| Chicken breast, meat only, roasted | 13.7 mg | 1/2 breast, 86 g | 11.8 mg |
| Peanuts, raw | 12.1 mg | 1 oz, 28 g | 3.4 mg |
| Light tuna, canned in water | 10.1 mg | 85 g | 8.6 mg |
| Atlantic mackerel, raw | 9.08 mg | 85 g | 7.7 mg |
| Atlantic salmon, farmed, raw | 8.67 mg | 85 g | 7.4 mg |
| Sunflower seed kernels, dried | 8.34 mg | 1/4 cup, 35 g | 2.9 mg |
| Pork tenderloin, lean, roasted | 7.43 mg | 85 g | 6.3 mg |
| Whole-wheat bread | 4.44 mg | 1 slice, 32 g | 1.4 mg |
| White mushrooms, raw | 3.61 mg | 1 cup pieces, 70 g | 2.5 mg |
| Brown rice, long-grain, cooked | 2.56 mg | 1 cup, 202 g | 5.2 mg |
Source: USDA FoodData Central, SR Legacy, checked 5 November 2026: beef liver FDC 168627, chicken breast FDC 171477, peanuts FDC 172430, light tuna FDC 173709, mackerel FDC 175119, salmon FDC 175167, sunflower seeds FDC 170562, pork tenderloin FDC 168250, whole-wheat bread FDC 172688, mushrooms FDC 169251, brown rice FDC 169704. The figures are preformed niacin; tryptophan adds niacin equivalents on top. Portions are USDA household measures (1/4 cup calculated from the cup weight); values per portion are calculated and rounded.
One portion of chicken, tuna, mackerel or salmon covers about half of a day’s niacin or more, before tryptophan is counted. Protein foods give extra: roasted chicken breast also has 0.362 g of tryptophan per 100 g, which equals about 6 mg NE more (our calculation from USDA FDC 171477). Plant eaters can combine peanuts, sunflower seeds, brown rice, whole-wheat bread and mushrooms. In some grains, much of the natural niacin is bound and poorly available (NIH). Corn is the classic case: it is low in tryptophan and its niacin is tightly bound, but soaking corn in limewater releases it (MedlinePlus).
Deficiency: signs and who is at risk
Severe deficiency causes pellagra, marked by a pigmented rash and scaly sores on skin exposed to the sun (NIH, MedlinePlus). Other signs are diarrhoea, abdominal pain, inflamed mucous membranes, a bright red tongue, weakness, loss of appetite, depression, confusion and delusions (MedlinePlus, NIH). Historically pellagra spread where diets were based mainly on corn.
Groups at risk (NIH, MedlinePlus):
- People with undernutrition, including alcohol use disorder.
- People with low intakes of riboflavin, vitamin B6 or iron, which the body needs to make niacin from tryptophan.
- People with Hartnup disease or carcinoid syndrome.
- People taking isoniazid for tuberculosis, and people with gut disease, after weight-loss surgery or with anorexia.
Supplements: when they make sense
Supplements use nicotinic acid or nicotinamide (also called niacinamide); nicotinamide riboside is a related form (NIH). The difference matters:
- Nicotinic acid causes flushing. From 30-50 mg the skin on the face, arms and chest can turn red, with burning, tingling and itching (NIH). It is also used as a medicine at 1,000 mg a day or more, where it can cause nausea, heartburn and abdominal pain.
- Nicotinamide has fewer side effects than nicotinic acid (NIH), and EFSA’s upper limit for it is 900 mg against 10 mg for nicotinic acid. Very high doses, 3,000 mg a day or more, can still cause nausea, vomiting and liver damage.
Heart disease. Trials of high-dose nicotinic acid in heart patients did not show fewer heart events. In a trial of 3,414 patients with established cardiovascular disease, adding it did not reduce events, and the largest trial to date, HPS2-THRIVE, found no significant reduction in major vascular events (NIH). Experts do not recommend high doses of nicotinic acid for people taking a statin (NIH).
Food first: most people who eat meat, fish or a mix of protein foods get enough. A supplement makes sense when a doctor treats a deficiency or a condition that causes one.
Who should be careful
- Liver. Long-term high doses of nicotinic acid, especially extended-release forms, can damage the liver (NIH).
- Diabetes. Large doses of nicotinic acid, 1,500 mg a day or more, can raise blood sugar and weaken diabetes treatment; blood glucose should be monitored (NIH).
- Gout. Acute gout is a reason to stop nicotinic acid, and uric acid should be checked during treatment (NIH).
- Eyes. High doses have been linked to blurred vision and macular oedema (NIH).
- Tuberculosis drugs. Isoniazid and pyrazinamide interfere with making niacin from tryptophan (NIH).
- Dialysis. In haemodialysis studies, nicotinamide at 500-1,500 mg a day caused diarrhoea and a drop in blood platelets (NIH).
FAQ
What is the difference between niacin and niacinamide?
Both are vitamin B3. Niacin in the narrow sense is nicotinic acid, which causes flushing from about 30 mg; niacinamide (nicotinamide) has not been shown to cause it and has fewer side effects. EFSA’s upper limits reflect the difference: 10 mg a day for nicotinic acid, 900 mg for nicotinamide.
Why does niacin make my skin flush?
Nicotinic acid at 30-50 mg or more typically causes the face, arms and chest to redden, burn, tingle and itch. Nicotinamide has not been shown to cause it. If you want a B3 supplement without flushing, check which form the label lists.
Which foods are high in niacin?
Per 100 g in USDA data, beef liver has 17.5 mg, roasted chicken breast 13.7 mg, peanuts 12.1 mg and canned light tuna 10.1 mg. Mackerel, salmon, sunflower seeds, pork, brown rice and mushrooms add useful amounts.
Related entries and articles
- Canned tuna, salmon and mackerel
- Peanuts and sunflower seeds
- Brown rice and mushrooms
- Vitamin B2 (riboflavin) and vitamin B6
- Vitamin B1 (thiamine) and iron
- Mediterranean mackerel stew with tomatoes and olives
- Baked salmon with root vegetables
Sources
- EFSA NDA Panel: Scientific Opinion on Dietary Reference Values for niacin. EFSA Journal, pub 3759. efsa.europa.eu
- EFSA: Summary of Dietary Reference Values, version 4 (September 2017). efsa.europa.eu
- EFSA: Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF), version 11 (August 2025). efsa.europa.eu
- VKM (Norwegian Scientific Committee for Food and Environment): Nicotinic acid and nicotinamide – assessment of suggested maximum limits in food supplements. vkm.no
- Commission Regulation (EU) No 432/2012 – permitted health claims. legislation.gov.uk
- NIH Office of Dietary Supplements: Niacin, Fact Sheet for Health Professionals. ods.od.nih.gov
- NIH Office of Dietary Supplements: Niacin, Fact Sheet for Consumers. ods.od.nih.gov
- MedlinePlus: Pellagra. medlineplus.gov
- NHS: Vitamin B. nhs.uk
- USDA FoodData Central, SR Legacy: Beef liver, cooked, pan-fried (FDC 168627); Chicken, broilers or fryers, breast, meat only, cooked, roasted (FDC 171477); Pork tenderloin, lean, cooked, roasted (FDC 168250). fdc.nal.usda.gov
- USDA FoodData Central, SR Legacy: Fish, tuna, light, canned in water (FDC 173709); Fish, mackerel, Atlantic, raw (FDC 175119); Fish, salmon, Atlantic, farmed, raw (FDC 175167). fdc.nal.usda.gov
- USDA FoodData Central, SR Legacy: Peanuts, raw (FDC 172430); Sunflower seed kernels, dried (FDC 170562); Bread, whole-wheat (FDC 172688); Mushrooms, white, raw (FDC 169251); Rice, brown, long-grain, cooked (FDC 169704). fdc.nal.usda.gov
This page is for information only and is not medical or dietary advice.
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