Oral or parenteral treatment under medical care for deficiency or Wernicke encephalopathy; not a general wellness dose
Reviewed · Published
Thiamin
A water-soluble vitamin supporting carbohydrate metabolism and nerve function.
Established functions
- A water-soluble vitamin supporting carbohydrate metabolism and nerve function.
Dietary sources
- pork
- brown rice
- legumes
Claims and evidence
Claims that Thiamin alone prevents or treats disease, or invariably improves health without deficiency, are unsupported.
Japanese reference amounts
- Japanese adults (age and sex as specified): Adult men 1.2–1.4 mg/day; women 0.9–1.1 mg/day (RDA)
Amounts studied
- Oral or parenteral treatment under medical care for deficiency or Wernicke encephalopathy; not a general wellness dose
Tolerable upper limits
- No UL is established; this does not establish safety of unrestricted high doses.
Forms and bioavailability
Supplement forms: thiamin hydrochloride, thiamin mononitrate
- Heavy alcohol use impairs absorption and utilization.
Safety and interactions
Adverse effects
- rare gastrointestinal upset orally; allergic reactions with injections
Medicine and nutrient interactions
- loop diuretics, fluorouracil, alcohol
Contraindications and cautions
- Alcohol dependence or prolonged vomiting warrants prompt clinical assessment.
Practical selection
- Compare Thiamin amount per serving, form, allergens, and batch testing; prefer a single-ingredient product suited to the intended use.
Sources and review
- Dietary Reference Intakes for Japanese (2025)Ministry of Health, Labour and Welfare (Japan)
- NIH ODS vitamin fact sheetsNIH Office of Dietary Supplements
Daiki Minaki (editorial and evidence review) ·