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Vitamin B1 (Thiamin)

    DEA Class;  Rx, OTC

    Common Brand Names; vitamin B1

    • B Vitamins; 
    • Vitamins, Water-Soluble

    Forms thiamine pyrophosphate by combining with adenosine triphosphate; essential coenzyme in carbohydrate metabolism

    It helps your body turn food into energy. It’s also key for the structure of brain cells. Legumes, like black beans and lentils, and seeds are go-to sources. Pork and whole grains are also good. Most people get enough thiamin from the foods they eat, but pregnant and breastfeeding women need a little more. People with diabetes tend to have low levels of it.

    Food Sources

    Fresh fruits, corn, cashew nuts, potatoes, sweet potatoes, peas, wheat, milk, dates, black beans, etc.

    Thiamine (vitamin B1) helps the body cells change carbohydrates into energy. Getting enough carbohydrates is very important during pregnancy and breastfeeding. It is also essential for heart function and healthy nerve cells.

    For nutritional supplementation.
    For the recommended dietary allowance (RDA) of thiamine for nutritional supplementation in healthy individuals.
    For the treatment of beriberi.
    NOTE: If beriberi occurs in a breast-fed infant, both the lactating mother and the infant should receive treatment for thiamine deficiency.
    For the treatment of Wernicke/Korsakoff syndrome.
    For Wernicke encephalopathy prophylaxis.
    For the treatment of metabolic disorders including necrotizing encephalomyelopathy, maple syrup urine disease (MSUD), and lactic acidosis associated with pyruvate carboxylase deficiency.


    • Warmth
    • Anaphylaxis
    • Cyanosis
    • Diaphoresis
    • Restlessness
    • Angioneurotic edema
    • Pruritus
    • Urticaria
    • Pulmonary edema
    • Weakness
    • Tightness of the throat
    • Nausea

    In pregnancy (doses >RDA)

    Acute thiamine deficiency reported with dextrose administration; use caution when thiamine status uncertain

    Hypersensitivity reactions reported following repeated parenteral doses

    Parenteral products may contain aluminum; use caution in patients with impaired renal function

    Evaluate for additional vitamin deficiencies if patient diagnosed with thiamin deficiency; single vitamin deficiencies are rare

    Pregnancy Category: A (injectable); C (if >RDA)

    Lactation: Safe


    Males: 1.2 mg/day

    Females: 1.1 mg/day

    Pregnancy/Lactation: 1.4 mg/day


    IM: 5-30 mg three times daily (if critically ill); then 5-30 mg three times daily for 1 month

    Duration dependent on persistence of symptoms

    Wernicke Encephalopathy

    100 mg IV; then 50-100 mg/day IM or IV until consuming regular balanced diet

    Thiamin Deficiency

    1 tablet or capsule/day

    Need for thiamin increases when carbohydrate content of diet is high

    Vitamin B1 (Thiamin)


    • 50mg
    • 100mg
    • 250mg


    • 50mg

    injectable solution

    • 100mg/mL