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Vitamins

Niacin (Vitamin B3)

Niacin is a water-soluble B vitamin needed for cellular metabolism. The name covers nicotinic acid and nicotinamide.

Nutrient11 authorised EU claims33 sources

Niacin, also called vitamin B3, is an umbrella term for nicotinic acid and nicotinamide. Both forms have the same vitamin function and provide building blocks for the coenzymes NAD and NADP. These participate in many metabolic reactions, including those involved in releasing and using energy. You obtain niacin from food, and your body can also make it from the amino acid tryptophan. Niacin is a nutrient rather than a food in its own right. Nicotinamide is also known as niacinamide.

What is niacin?

Niacin, also known as vitamin B3, is a water-soluble B vitamin. The term includes nicotinic acid and nicotinamide. Both forms have the same vitamin function and provide building blocks for the coenzymes NAD and NADP.

What does niacin do?

NAD and NADP take part in many metabolic reactions, including the release and use of energy from nutrients. Niacin contributes to normal energy-yielding metabolism, normal nervous system function and normal psychological function. It also contributes to the maintenance of normal skin and mucous membranes, and to the reduction of tiredness and fatigue.

Niacin in the diet

You get niacin from food. Your body can also make it from the amino acid tryptophan. For calculating niacin equivalents, 60 mg of tryptophan corresponds to about 1 mg of niacin. Niacin equivalents therefore account for both niacin from food and the contribution from tryptophan.

How nutrition works

Statements & evidence

  • Niacin contributes to normal energy-yielding metabolism. [3]

    Niacin helps your body use energy from food. This claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin contributes to normal functioning of the nervous system. [3]

    This describes normal nervous-system function, not treatment of neurological conditions. The claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin contributes to normal psychological function. [3]

    This does not mean that additional niacin supplements improve your mood or concentration. The claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin contributes to the maintenance of normal skin. [3]

    This concerns niacin’s nutritional role, not treatment of skin conditions. The claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin contributes to the maintenance of normal mucous membranes. [3]

    Mucous membranes line areas such as your mouth and parts of your digestive tract. This claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin contributes to the reduction of tiredness and fatigue. [3]

    This does not mean that extra niacin relieves every form of tiredness when your intake is already adequate. The claim may only be used for foods that meet the legal conditions for a source of niacin.

    Authorised EU health claim · Commission Regulation (EU) No 432/2012, Annex

  • Niacin requirements are related to energy requirements. EFSA sets a population reference intake of 1.6 mg niacin equivalents per MJ, equivalent to approximately 6.6 mg per 1,000 kcal. [2]

    This energy-related reference applies to adults, children from seven months of age, adolescents, and pregnant and breastfeeding women. It concerns dietary adequacy, not a treatment or supplement dose.

    Nutrition factEvidence: strong

  • Your body can make niacin from the amino acid tryptophan. When calculating niacin equivalents, 60 mg of tryptophan is equivalent to approximately 1 mg of niacin. [2]

    Niacin equivalents account for both dietary niacin and the contribution from tryptophan. This ratio is a convention for nutritional assessment; actual conversion can vary.

    Nutrition factEvidence: strong

  • High doses of nicotinic acid, a form of niacin, can cause flushing, gastrointestinal symptoms and liver injury. [4]

    Risks depend on dose and formulation. Nicotinic acid and nicotinamide have different safety profiles. Do not take high-dose niacin supplements without medical supervision.

    EvidenceEvidence: strong

Safety information

  • Caution

    The form of niacin matters

    Nicotinic acid and nicotinamide have different adverse effects and upper intake levels. If you take a supplement, check which form it contains: their safety limits are not interchangeable and are not expressed as niacin equivalents. [4]

  • Upper level · Adults

    Free nicotinic acid: adult upper intake level

    For adults who are not pregnant or breastfeeding, the tolerable upper intake level is 10 mg of free nicotinic acid per day. It concerns habitual daily intake, excludes nicotinic acid naturally bound in foods, and is not a recommended intake. Medically supervised therapeutic use falls outside its scope. [5][4]

  • Upper level · Adults

    Nicotinamide: adult upper intake level

    For adults who are not pregnant or breastfeeding, the tolerable upper intake level for nicotinamide is 900 mg per day. This is a limit for habitual daily intake, not a recommended supplement dose or a guarantee of individual tolerance. [5]

  • Upper level · Children and adolescents (1–17 years)

    Free nicotinic acid: lower limits for children

    Daily tolerable upper intake levels for free nicotinic acid are: 2 mg at ages 1–3, 3 mg at 4–6, 4 mg at 7–10, 6 mg at 11–14 and 8 mg at 15–17. They exclude nicotinic acid naturally bound in foods and are not intake targets. [5][4]

  • Upper level · Children and adolescents (1–17 years)

    Nicotinamide: upper limits for children and adolescents

    Daily tolerable upper intake levels for nicotinamide are: 150 mg at ages 1–3, 220 mg at 4–6, 350 mg at 7–10, 500 mg at 11–14 and 700 mg at 15–17. These limits are not recommended supplement doses. [5]

  • Caution

    No established upper limits for pregnancy, breastfeeding or infancy

    No tolerable upper intake levels have been established for nicotinic acid or nicotinamide during pregnancy, breastfeeding or infancy. This does not mean that unrestricted amounts are safe. Avoid high-dose niacin supplements in these groups without medical advice. [5]

  • Side effect

    Nicotinic acid can cause flushing

    Free nicotinic acid in supplements can cause temporary skin flushing, warmth and itching. Nicotinamide does not cause this characteristic flush. This risk should not be equated with ordinary niacin intake from foods. [4]

  • Side effect · Adults

    High doses of nicotinic acid can harm the liver

    Nicotinic acid at high therapeutic doses can cause liver injury. Some sustained-release preparations have shown greater liver toxicity than immediate-release preparations. Take such doses only under medical supervision, especially if you have liver disease; ordinary dietary intake is not equivalent to this exposure. [4]

  • Interaction · Adults

    Caution with diabetes and glucose-lowering medicines

    High doses of nicotinic acid can worsen blood glucose control. An increased need for glucose-lowering medication has been reported in people with diabetes. If you have diabetes or take these medicines, use high-dose nicotinic acid only with medical advice and do not adjust your medication yourself. [4]

  • Side effect · Adults

    Digestive effects of high-dose nicotinic acid

    Nausea, vomiting, diarrhoea and constipation have been reported with high therapeutic doses of nicotinic acid. These observations do not concern ordinary niacin intake from foods. [4]

  • Side effect · Adults

    High-dose nicotinamide is not risk-free

    Although nicotinamide does not cause the characteristic flush, nausea and hepatitis have been reported at high doses. The evidence is limited and does not establish a reliable dose threshold for these adverse effects. [4]

Found in

Frequently asked questions

What is niacin?

Niacin is a water-soluble B vitamin that your body needs for cellular metabolism. It includes nicotinic acid and nicotinamide.

What does the body need niacin for?

Niacin contributes to normal energy metabolism, normal nervous system function and normal psychological function. It also contributes to the maintenance of normal skin and the reduction of tiredness and fatigue.

How much niacin do you need each day?

Niacin requirements are related to energy needs. EFSA gives a reference intake of 1.6 mg niacin equivalents per MJ, or about 6.6 mg per 1,000 kcal.

Can the body make niacin, and are high doses safe?

Your body can make niacin from tryptophan: 60 mg of tryptophan correspond to about 1 mg of niacin. High doses of nicotinic acid can cause skin flushing and warmth, digestive symptoms and liver damage.

  • Folate

    Folate is a water-soluble B vitamin. Its active forms take part in DNA synthesis and amino-acid metabolism.

  • Vitamin A

    Vitamin A is an essential, fat-soluble vitamin. Your diet supplies it as preformed vitamin A or as precursors from plant foods.

  • Vitamin B1 (thiamin)

    Vitamin B1 is a water-soluble vitamin. In its coenzyme form, it helps your body metabolise nutrients, particularly carbohydrates.

  • Vitamin B12

    Vitamin B12 is an essential, water-soluble vitamin. Your body needs it for normal nervous-system function, red blood cell formation and DNA synthesis.

  • Vitamin B2 (Riboflavin)

    Vitamin B2, also called riboflavin, is a water-soluble vitamin involved in energy metabolism and many enzyme reactions.

  • Vitamin C

    Vitamin C is an essential, water-soluble vitamin that you need to obtain through your diet. Its principal chemical form is L-ascorbic acid.

Sources

  1. 01EFSA Journal · 2009Scientific Opinion on the substantiation of health claims related to niacin and energy-yielding metabolism, function of the nervous system, maintenance of the skin and mucous membranes, maintenance of normal LDL-cholesterol, HDL cholesterol and triglyceride concentrations, maintenance of bone, teeth, hair and nails pursuant to Article 13(1) of Regulation (EC) No 1924/2006EFSA Panel on Dietetic Products, Nutrition and AllergiesDOI 10.2903/j.efsa.2009.1224
  2. 02EFSA Journal · 2014Scientific Opinion on Dietary Reference Values for niacinDOI 10.2903/j.efsa.2014.3759
  3. 03European Commission · 2012Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children's development and healthOpen source
  4. 04Scientific Committee on Food; EFSA Scientific Panel on Dietetic Products, Nutrition and Allergies · 2006Tolerable Upper Intake Levels for Vitamins and MineralsOpen source
  5. 05European Food Safety AuthoritySummary tables of tolerable upper intake levels for vitamins and minerals, version 8Open source
  6. 06ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Almond, with peel, no added salt (CIQUAL 15000)Open source
  7. 07ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Apple, flesh and skin, raw (CIQUAL 13039)Open source
  8. 08ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Broccoli, raw (CIQUAL 20057)Open source
  9. 09ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Carrot, raw (CIQUAL 20009)Open source
  10. 10ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Chia, seed, dried (CIQUAL 15047)Open source
  11. 11ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Chick pea, dried (CIQUAL 20516)Open source
  12. 12ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Egg, raw (CIQUAL 22000)Open source
  13. 13ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Lentil, dried (average) (CIQUAL 20359)Open source
  14. 14ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Oat flakes (CIQUAL 32140)Open source
  15. 15ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Orange, flesh without skin, without seeds, raw (CIQUAL 13034)Open source
  16. 16ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Potato, peeled, raw (CIQUAL 4008)Open source
  17. 17ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Pumpkin and squash, seed, dried (CIQUAL 15064)Open source
  18. 18ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Quinoa, raw (CIQUAL 9340)Open source
  19. 19ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Salmon, raw, farmed (CIQUAL 26036)Open source
  20. 20ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Spinach, raw (CIQUAL 20059)Open source
  21. 21ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Tofu, plain, prepacked (CIQUAL 20904)Open source
  22. 22ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Tomato, raw (average) (CIQUAL 20385)Open source
  23. 23ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Tuna, raw (CIQUAL 26053)Open source
  24. 24ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Walnut, kernel, dried (CIQUAL 15005)Open source
  25. 25ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Avocado, flesh without skin, pitted, raw (CIQUAL 13004)Open source
  26. 26ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Beef, round, raw (CIQUAL 6102)Open source
  27. 27ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Sweet pepper, red, raw (CIQUAL 20087)Open source
  28. 28ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Blueberry, raw (CIQUAL 13028)Open source
  29. 29ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Chicken, breast, without skin, raw (CIQUAL 36017)Open source
  30. 30ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Atlantic herring, raw (CIQUAL 26011)Open source
  31. 31ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Milk, semi-skimmed (average) (CIQUAL 19033)Open source
  32. 32ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Button mushroom or cultivated mushroom, raw (CIQUAL 20056)Open source
  33. 33ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Olive oil, extra virgin (CIQUAL 17270)Open source