The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
The U.S. recommended dietary allowance (RDA) for adults aged 19 years and older is 1.2 milligrams daily for males and 1.1 milligrams daily for females, taken by mouth. The RDA for pregnant or breastfeeding women of any age is 1.4 milligrams daily, taken by mouth. As a dietary supplement in adults, 1-2 milligrams of thiamine has been used daily, by mouth.
For Alzheimer's disease, three milligrams of thiamine has been used daily by mouth in three divided doses for up to one year.
For dysmenorrhea, 100 milligrams of thiamine has been used daily by mouth for three months.
For epilepsy, 50 milligrams of thiamine has been used daily by mouth for six months.
Thiamine is used to treat thiamine deficiency, metabolic or genetic enzyme deficiency disorders, neuropathy, and Wernicke's encephalopathy (prevention and treatment) under medical supervision.
For alcohol withdrawal, 100 milligrams of intramuscular (injected into the muscle) or intravenous (injected into the vein) thiamine hydrochloride has been used before administration of dextrose solutions.
For alcoholic liver disease patients, 100 milligrams of parenteral (injected) thiamine has been used.
For coma or hypothermia of unknown origin, 100 milligrams of intramuscular or intravenous thiamine has been used at the same time as hypertonic dextrose.
For total parenteral nutrition-induced fulminant beriberi, 100 milligrams of rapid intravenous thiamine has been used, with transfer to an intensive care unit.
For Wernicke-Korsakoff syndrome, the following daily doses have been used: 5-200 milligrams of intramuscular thiamine (administered in five divided doses over two days in patients with Wernicke-Korsakoff syndrome secondary to alcohol abuse); and at least 100 milligrams of intravenous or intramuscular thiamine.
Children (younger than 18 years)
The adequate intake (AI) for infants 0-6 months old is 0.2 milligrams, and for infants 7-12 months old, the AI is 0.3 milligrams. For children 1-3 years old, the U.S. recommended dietary allowance (RDA) is 0.5 milligrams; for children 4-8 years old, it is 0.6 milligrams; for children 9-13 years old, it is 0.9 milligrams; for males 14-18 years old, it is 1.2 milligrams; and for females 14-18 years old, it is one milligram, taken by mouth daily. The RDA for pregnant or breastfeeding women of any age is 1.4 milligrams daily, taken by mouth. Thiamine is used to treat thiamine deficiency or beriberi under medical supervision.