Thiamin (vitamin B-1) helps the body generate energy from nutrients. Also known as thiamine, thiamin is necessary for the growth, development and function of cells.

Most people get enough thiamin from the food they eat. Foods rich in thiamin include yeast, legumes, pork, brown rice, as well as fortified foods, such as breakfast cereals. However, heating foods containing thiamin can reduce thiamin content. Thiamin can also be taken as a supplement, typically orally.

People who have had bariatric surgery, have conditions such as HIV/AIDS, are chronic alcoholics, or use drugs such as the diuretic furosemide (Lasix), are at risk of a thiamin deficiency. Thiamin deficiency can lead to the neurological condition Wernicke-Korsakoff’s syndrome or beriberi, a condition that involves peripheral nerve damage.

People also take thiamin to treat inherited metabolic disorders.

The recommended daily amount of thiamin for adult men is 1.2 milligrams and for adult women is 1.1 milligrams.


Research on thiamin use for specific conditions shows:

  • Inherited metabolic disorders. Oral thiamin helps temporarily correct different types of medical conditions caused by genetic defects — most commonly inherited from both parents — that interfere with the body’s metabolism. One example is maple syrup urine disease.

Our take

Green light: Generally safe

Generally safe

A healthy and varied diet will provide most people with enough thiamin. However, for people who have had bariatric surgery, have conditions such as HIV/AIDS, are chronic alcoholics or use certain drugs, a thiamin supplement might be necessary. Thiamin is generally safe.

Safety and side effects

When used as an oral supplement in appropriate doses, thiamin is likely safe. Rarely, it can cause a skin reaction.


There’s currently no evidence to show that thiamin interacts with other drugs.

However, regular chewing of areca (betel) nuts or frequently eating raw fish or shellfish might contribute to thiamin deficiency.

Nov. 14, 2020