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Vitamins

Vitamin B1 (thiamin)

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

Nutrient4 authorised EU claims34 sources

Vitamin B1, also called thiamin or thiamine, belongs to the B-vitamin family. Your body converts it into the coenzyme form thiamin pyrophosphate (TPP). This supports enzymes in metabolic reactions, including those involved in releasing energy from nutrients. Supplements and fortified foods often provide vitamin B1 as thiamin hydrochloride or thiamin mononitrate. These compounds supply the same vitamin but are distinct from its active coenzyme form.

What is vitamin B1?

Vitamin B1, also called thiamin, is a water-soluble B vitamin. Your body converts it into thiamin pyrophosphate (TPP), an active coenzyme form.

What does thiamin do?

TPP supports enzymes in metabolic reactions, including those involved in releasing energy from nutrients. Thiamin contributes to normal energy-yielding metabolism, normal functioning of the nervous system and normal heart function. It also contributes to normal psychological function.

Vitamin B1 in supplements and fortified foods is often used as thiamin hydrochloride or thiamin mononitrate. These compounds provide the same vitamin, but are distinct from its active coenzyme form, TPP.

How nutrition works

  • Evidence: strong

    Energy metabolism

    • Vitamin B1 contributes to normal energy-yielding metabolism. [1]

      Evidence

  • Evidence: strong

    Nervous system

    • Vitamin B1 contributes to normal nervous-system function. [2]

      Evidence

  • Evidence: strong

    Cardiovascular health

    • Vitamin B1 is important for normal cardiovascular function. [2]

      Evidence

Statements & evidence

  • Thiamine contributes to normal energy-yielding metabolism. [3][1]

    Vitamin B1 helps your body use energy from food. This does not establish an additional benefit from high-dose supplements. The claim may only be used for foods that meet the EU conditions for being a source of thiamine.

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

  • Thiamine contributes to normal functioning of the nervous system. [3][2]

    An adequate supply of vitamin B1 supports normal nerve function. The claim may only be used for foods that meet the EU conditions for being a source of thiamine.

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

  • Thiamine contributes to normal psychological function. [3]

    This claim describes a normal nutrient function, not a demonstrated improvement in memory or concentration from additional intake. It may only be used for foods that meet the EU conditions for being a source of thiamine.

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

  • Thiamine contributes to the normal function of the heart. [3][2]

    Vitamin B1 is needed for normal heart function. This claim does not mean that additional intake prevents or treats heart disease. It may only be used for foods that meet the EU conditions for being a source of thiamine.

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

Safety information

  • Side effect

    Low observed toxicity when taken by mouth

    Vitamin B1 showed low toxicity when taken by mouth in the reports assessed. This does not mean that arbitrarily high supplement doses are safe over the long term. [5]

  • Upper level

    No tolerable upper intake level established

    A tolerable upper intake level (UL) could not be established for vitamin B1 because the data were insufficient. This does not imply that unlimited intake is safe. [5]

  • Side effect

    Rare severe allergic reactions to injections

    Rare severe allergic reactions, including anaphylaxis, have been reported in people receiving vitamin B1 injections. This warning concerns injected medical treatment, not vitamin B1 in food. [5]

  • Caution · Adults

    Heavy alcohol consumption can contribute to deficiency

    If you drink heavily, vitamin B1 absorption and utilisation can be impaired. This concerns the risk of deficiency and does not mean that vitamin B1 is inherently unsuitable for you. [5]

Found in

Frequently asked questions

What is vitamin B1?

Vitamin B1, also called thiamin, is a water-soluble B vitamin.

What does the body need vitamin B1 for?

Vitamin B1 contributes to normal energy-yielding metabolism and the normal functioning of the nervous system and psychological function.

In what form does vitamin B1 act as a coenzyme?

The coenzyme form of vitamin B1 is thiamin pyrophosphate (TPP), also called thiamin diphosphate.

Does vitamin B1 support heart function?

Thiamin contributes to normal heart function.

  • Folate

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

  • Niacin (Vitamin B3)

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

  • 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 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. 01European Food Safety Authority · 2017Dietary Reference Values for nutrients: Summary reportOpen source
  2. 02European Food Safety Authority · 2016Dietary reference values: EFSA publishes advice on thiamin (vitamin B1)Open source
  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. 04European Parliament and Council of the European Union · 2011Regulation (EU) No 1169/2011 on the provision of food information to consumersOpen source
  5. 05Scientific Committee on Food; EFSA Scientific Panel on Dietetic Products, Nutrition and Allergies · 2006Tolerable Upper Intake Levels for Vitamins and MineralsOpen 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 · 2025Tuna, raw (CIQUAL 26053)Open source
  23. 23ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Walnut, kernel, dried (CIQUAL 15005)Open source
  24. 24ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Yogurt or fermented milk, plain (CIQUAL 19593)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 · 2025Rice, wholegrain, raw (CIQUAL 9102)Open source
  30. 30ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Chicken, breast, without skin, raw (CIQUAL 36017)Open source
  31. 31ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Atlantic herring, raw (CIQUAL 26011)Open source
  32. 32ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Milk, semi-skimmed (average) (CIQUAL 19033)Open source
  33. 33ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Button mushroom or cultivated mushroom, raw (CIQUAL 20056)Open source
  34. 34ANSES – French Agency for Food, Environmental and Occupational Health & Safety – Ciqual French food composition table · 2025Olive oil, extra virgin (CIQUAL 17270)Open source