Vitamin B1, also known as thiamine, was the first of the B vitamins to be discovered. It was isolated in 1926 as a water soluble, crystalline yellowish white powder with a salty, slightly nutty taste. Scientists now know that vitamin B1 plays an important role in producing energy for the body’s cells.

Because it is water soluble, thiamine is not stored in the body and must be supplied daily. In adults, chronic dieting, alcoholism, and diets consisting primarily of highly processed, refined foods are causes of thiamine deficiency.


Dosage Info

Dosage Range

1.5-100mg daily, depending on the presence and severity of a deficiency. Doses of 300mg or more per day have been used therapeutically for neurological conditions such as Kearns-Sayre syndrome and Leigh’s disease. (1) , (2)

Most Common Dosage

5mg daily.

Dosage Forms

Tablets, capsules, liquids, liposomal sprays, effervescent tablets, and injectable (Rx only).

Interactions and Depletions



Reported Uses

In addition to its role in converting blood sugar to energy for cells, thiamine supports nerve tissues and nerve function. It is also necessary for healthy muscle function, especially in the heart. Thiamine is involved in the conversion of fatty acids and amino acids into hormones, proteins and enzymes.

Supplementation with thiamine may support health for those suffering from a variety of disorders. Studies suggest that alcoholics may be depleted of vitamin B1. (3) Supplementation may help alcoholics metabolize alcohol more effectively, which may support recovery from addiction. (4)

Meanwhile, thiamine may support health in people with Alzheimer’s disease. (5) Supplementation may also be of benefit to those suffering from a number of other neurological conditions including sensory neuropathy, (6) sciatica and Bell’s palsy, as well as insomnia. (7) , (8) Studies also indicate that most psychiatric patients are deficient in thiamine. (9)

Deficiency in vitamin B1 has also been associated with the use of diuretic drugs used to treat congestive heart failure. (10) Studies indicate that people who have diabetes may also be thiamine deficient. (11) Finally, anemia may be responsive to supplementation with thiamine. (12) , (13)

Toxicities & Precautions


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This dietary supplement is considered safe when used in accordance with proper dosing guidelines.

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Proper nutrition is essential during pregnancy for the healthy development of the fetus. Numerous vitamins and minerals are a vital part of proper nutrition. If you are pregnant, think you might be pregnant, trying to get pregnant, or breast-feeding an infant, talk to your healthcare professional about supplementing your diet with appropriate vitamins and minerals.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Vitamins and minerals are an essential part of proper growth and development. Talk to your healthcare professional about the appropriate use of vitamins and minerals in children. Do not use any vitamin or mineral in children under 2 years of age unless first discussed with your healthcare professional.


  1. Lou HC. Correction of increased plasma pyruvate and plasma lactate levels using large doses of thiamine in patients with Kearns-Sayre syndrome. Arch Neurol. Jul 1981;38(7):469.
  2. View Abstract: Kissel JT, Kolkin S, Chakeres D, Boesel C, Weiss K. Magnetic resonance imaging in a case of autopsy-proved adult subacute necrotizing encephalomyelopathy (Leigh’s disease). Arch Neurol. May1987;44(5):563-6.
  3. View Abstract: Heap LC, Pratt OE, Ward RJ, et al. Individual susceptibility to Wernicke-Korsakoff syndrome and alcoholism-induced cognitive deficit: impaired thiamine utilization found in alcoholics and alcohol abusers. Psychiatr Genet. Dec2002;12(4):217-24.
  4. View Abstract: Cook CC, et al. B Vitamin Deficiency and Neuropsychiatric Syndromes in Alcohol Misuse. Alcohol Alcohol. Aug1998;33(4):317-36.
  5. View Abstract: Mimori Y, et al. Thiamine Therapy in Alzheimer’s Disease. Metab Brain Dis. Mar1996;11(1):89-94.
  6. View Abstract: Ishibashi S, Yokota T, Shiojiri T, et al. Reversible acute axonal polyneuropathy associated with Wernicke-Korsakoff syndrome: impaired physiological nerve conduction due to thiamine deficiency? J Neurol Neurosurg Psychiatry. May2003;74(5):674-6.
  7. View Abstract: Crespi F, et al. Sleep and Indolamine Alterations Induced by Thiamine Deficiency. Brain Res. Sep1982;248(2):275-83.
  8. View Abstract: Skelton WP, 3rd, et al. Thiamine Deficiency Neuropathy. It’s Still Common Today. Postgrad Med. Jun1989; 85(8):301-06.
  9. Carney MW. Vitamin Deficiency and Mental Symptoms. Br J Psychiatry. Jun1990;156:878-82.
  10. View Abstract: Seligmann H, et al. Thiamine Deficiency in Patients with Congestive Heart Failure Receiving Long-term Furosemide Therapy: A Pilot Study. Am J Med. Aug1991;(2):151-55.
  11. View Abstract: Saito N, et al. Blood Thiamine Levels in Outpatients with Diabetes Mellitus. J Nutr Sci Vitaminol.(Tokyo). Dec1987;33(6):421-30.
  12. Mandel H, et al. Thiamine-dependent Beriberi in the Thiamine-responsive Anemia Syndrome. N Engl J Med. Sep1984;311(13):836-38.
  13. View Abstract: Boros LG, Steinkamp MP, Fleming JC, Lee WN, Cascante M, Neufeld EJ. Defective RNA ribose synthesis in fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA). Blood. Jul2003. [Epub ahead of print].