Vitamin B1

Supplement Forms/Alternate Names :

Thiamine, thiamin


Vitamin B1 is found in nuts, beans, and yeast. The body needs it to create energy. Vitamin B1 has been used to improve heart health and ease digestion. It has also been used to manage thiamine deficiency. It can be taken as a pill or powder. It can also be injected into the bloodstream or muscle by a healthcare provider.


1 to 1.2 milligrams per day for adults

What Research Shows

May Be Effective

Unlikely to Be Effective

  • Glaucoma —unlikely to provide benefit C1

Not Enough Data to Assess

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to vitamin B1 in small doses for a short time. Not enough studies have been done to say whether it is safe to take for a long period.

Women who are pregnant or breastfeeding should not take high doses of vitamin B1.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Alcohol Abuse

A1. Day E, Bentham PW, et al. Thiamine for prevention and treatment of Wernicke-Korsakoff Syndrome in people who abuse alcohol. Cochrane Database Syst Rev. 2013;(7):CD004033.

B. Alzheimer Disease

B1. Rodríguez-Martín JL, Qizilbash N, et al. Thiamine for Alzheimer's disease. Cochrane Database Syst Rev. 2001;(2):CD001498.

C. Glaucoma

C1. Ramdas WD, Schouten JSAG, et al. The Effect of Vitamins on Glaucoma: A Systematic Review and Meta-Analysis. Nutrients. 2018 Mar 16;10(3). pii: E359.

D. Heart Failure

D1. DiNicolantonio JJ, Niazi AK, et al. Thiamine supplementation for the treatment of heart failure: a review of the literature. Congest Heart Fail. 2013 Jul-Aug;19(4):214-222.

D2. Jain A, Mehta R, et al. Determining the Role of Thiamine Deficiency in Systolic Heart Failure: A Meta-Analysis and Systematic Review. J Card Fail. 2015;21(12):1000-1007.

E. Menstrual Cramps

E1. Hosseinlou A, Alinejad V, et al. The effects of fish oil capsules and vitamin B1 tablets on duration and severity of dysmenorrhea in students of high school Urmia-Iran. Glob J Health Sci. 2014;6(7):124-129.

E2. Pattanittum P, Kunyanone N, et al. Dietary supplements for dysmenorrhoea. Cochrane Database Syst Rev. 2016 Mar 22;3:CD002124.

F. Premenstrual Syndrome

F1. Avdollahifard S, Rahmanian Koshkaki A, et al. The effects of vitamin B1 on ameliorating the premenstrual syndrome symptoms. Glob J Health Sci. 2014;6(6):144-153.

G. Wernicke Encephalopathy in Anorexia Nervosa

G1. Oudman E, Wijnia JW, et al. Preventing Wernicke's encephalopathy in anorexia nervosa: A systematic review. Psychiatry Clin Neurosci. 2018 Oct;72(10):774-779.

Last reviewed July 2019 by EBSCO NAT Review Board Eric Hurwitz, DC