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Medical and Pharmacy Editor:

Brand Name: Vitamin B1

Generic Name: Thiamine

Drug Class: B Vitamins; Vitamins, Water-Soluble

What Is Thiamine and How Does It Work?

Thiamine is a prescription and over-the-counter (OTC) vitamin, also called vitamin B1. Vitamin B1 is found in many foods including yeast, cereal grains, beans, nuts, and meat. It is often used in combination with other B vitamins.

Thiamine is taken for conditions related to low levels of thiamine, including beriberi and inflammation of the nerves (neuritis) associated with pellagra or pregnancy. Thiamine is also used for digestive problems including poor appetite, ulcerative colitis, and ongoing diarrhea.

Thiamine is also used for AIDS and boosting the immune system, diabetic pain, heart disease, alcoholism, aging, a type of brain damage called cerebellar syndrome, canker sores, vision problems such as cataracts and glaucoma, motion sickness, and improving athletic performance. Other uses include preventing cervical cancer and progression of kidney disease in patients with type 2 diabetes.

Some people use thiamine for maintaining a positive mental attitude; enhancing learning abilities; increasing energy; fighting stress; and preventing memory loss, including Alzheimer's disease.

Healthcare providers give thiamine shots for a memory disorder called Wernicke's encephalopathy syndrome, other thiamine deficiency syndromes in critically ill people, alcohol withdrawal, and coma.

Thiamine is available under the following different brand names: vitamin B1.

Dosages of Thiamine:

Adults and Pediatric Dosages


  • 50 mg
  • 100 mg
  • 250 mg


  • 50 mg

Injectable solution

  • 100 mg/ml

Dosage Considerations – Should be Given as Follows:

Recommended Daily Average


  • Males: 1.2 mg/day
  • Females: 1.1 mg/day
  • Pregnancy/Lactation: 1.4 mg/day


  • Infants 0-6 months: 0.2 mg/day
  • Infants 6-12 months: 0.3 mg/day
  • Children 1-3 years old: 0.5 mg/day
  • Children 3-8 years old: 0.6 mg/day
  • Children 8-13 years old: 0.9 mg/day
  • Children 13-18 years old: 1.2 mg/day (male), 1 mg/day (female)


  • 10-50 mg/day orally in divided doses



  • Intramuscularly: 5-30 g three times daily (if critically ill); then 5-30 mg three times daily for 1 month
  • Duration dependent on persistence of symptoms


  • 10-25 mg intravenously/intramuscularly per day (if critically ill) or 10-50 mg dose orally per day for at least 2 weeks, then 5-10 mg/day orally for 1 month
  • Duration dependent on persistence of symptoms

Wernicke Encephalopathy

  • 100 mg intravenously; then 50-100 mg/day intramuscularly or intravenously until consuming regular balanced diet

Thiamin Deficiency

  • 1 tablet or capsule/day
  • Need for thiamin increased when carbohydrate content of diet is high
Medically Reviewed by a Doctor on 5/16/2017

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