Vitamin
Thiamine (Vitamin B1)
Also known as: vitamin B1, thiamin, thiamine HCl, thiamine pyrophosphate
Water-soluble B vitamin essential for energy metabolism and nervous system function. Acts as a coenzyme in carbohydrate metabolism and neurotransmitter synthesis.
Primary uses
- Energy metabolism
- Nervous system function
- Brain health and cognition
- Cardiovascular function
- Muscle function
How it works
- Serves as coenzyme (thiamine pyrophosphate) in carbohydrate metabolism
- Essential for pyruvate dehydrogenase complex function
- Required for transketolase in pentose phosphate pathway
- Supports neurotransmitter synthesis (acetylcholine, GABA)
- Necessary for myelin formation
Dosage
- Typical range
- 1.1 mg daily RDA (women 50+: 1.1 mg); supplements typically 25-100 mg
- Timing
- With meals to enhance absorption
- With food
- Absorption enhanced with food; may cause GI upset on empty stomach
- Duration
- Safe for long-term daily use. Water-soluble excess is excreted in urine.
- Special populations
- Women 50+ have same RDA as younger women. Older adults with poor nutrition, chronic diarrhea, or alcohol use disorder at increased risk of deficiency.
Forms
- thiamine HCl· 70/100
- thiamine mononitrate· 70/100
- thiamine pyrophosphate (TTFD)· 70/100
Safety
Common side effects
- Rare at recommended doses
- Very high doses may cause nausea, headache, or irritability
Contraindications
- None at supplemental doses
Evidence notes
Strong evidence for deficiency correction and energy metabolism support. Well-established essential nutrient with clear clinical evidence for neurological function.
Grade A: Multiple well-designed human trials support the main claims.
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