Thiamine (Vitamin B1) Supplement Review

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Thiamine (Vitamin B1)
  Evaluated for:
Effectiveness Rating Effectiveness Rating
Thiamine Deficiency
+3 (Strong Evidence)
People at risk for Thiamine Deficiency
+1 (Slight Evidence)


  • Thiamine (vitamin B1) is a water-soluble vitamin and one of the first organic compounds to have been recognized as a vitamin. Dietary sources are essential. Foods rich in thiamine include brewer’s yeast, lentils, beans, nuts, oatmeal, flax, sunflower seeds, brown rice, whole grains, whole grain rye, asparagus, kale, cauliflower, potatoes, oranges, liver, and eggs, among others.
  • Thiamine is involved in numerous cellular processes. These affect nerve and muscle function, enzyme reactions, and even production of hydrochloric acid, necessary for proper digestion.
  • Thiamine is not stored in the body, so depletion can occur quickly, within 14 days. Severe chronic thiamine deficiency, called beriberi, can cause serious injury to the brain and other nerve tissue, heart and other muscles, and gastrointestinal tract. Signs of deficiency are nonspecific, and may include weight loss, irritability, confusion, and malaise. Thiamine deficiency can be fatal if left untreated.
  • Mild thiamine deficiencies are common because they affect many different populations, including those with diabetes, alcoholism, HIV, advanced age, celiac, bariatric surgery, cancer, heart disease, and numerous other medical conditions. Thiamine deficiency is also associated with heart failure.


  • Thiamine supplementation in individuals with low levels of several other B vitamins, mainly pyridoxine (vitamin B6) and niacin (vitamin B3), may cause a potentially life-threatening disease called “pellagra encephalopathy.”
  • Populations at higher risk of this complication include the elderly as well as those with a history of malnutrition or alcohol abuse.
  • High doses of thiamine in individuals with a deficiency may temporarily lower systolic (the upper number) blood pressure levels.


DOSAGE:The recommended oral dose for ages 19 years and older is 1.2 mg daily for males, 1.1 mg daily for females, and 1.4 mg daily for pregnant or breastfeeding women.

CONCLUSION:We conclude that thiamine (vitamin B1) is a safe and effective product for the treatment of thiamine deficiency. Remember to include it in your list of medications when you visit your doctor and other health care providers. Take a multivitamin with it to make sure you also get enough B3 and B6.

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