Overview
Cofactor for carbohydrate metabolism and nerve conduction.
- Pork
- Sunflower seeds
- Legumes
- Whole grains
- Thiamine HCl
- Benfotiamine (lipid-soluble)
- Sulbutiamine
Forms & variants of Vitamin B1 (Thiamine)
Different chemical forms of Vitamin B1 (Thiamine) behave differently. Browse each form's mechanism, bioavailability, and best-use context.
Mechanism of action
TPP cofactor for pyruvate dehydrogenase and α-ketoglutarate dehydrogenase.
- · Krebs cycle
- · Pentose phosphate pathway
Effects on the body
Organ system effects
Deficiency causes Wernicke encephalopathy.
Deficiency causes wet beriberi.
Evidence-based benefits
Treats/prevents Wernicke-Korsakoff
Strong evidenceBenfotiamine reduces diabetic neuropathy symptoms
Moderate evidencePotential side effects
- · Vitamin B1 (Thiamine) is generally well-tolerated at evidence-based doses
- · Mild GI discomfort (nausea, loose stools, or bloating) possible at higher intakes
- · Headache or transient fatigue reported by a small fraction of users
- · Allergic or hypersensitivity reaction (rash, itching, swelling)
- · Sleep disturbance if taken late in the day
- · Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing
Drug interactions
Supplement interactions
- Omega-3 (EPA/DHA)Membrane fluidity and neuronal signaling support.
- Alpha-GPC or CDP-cholineProvides choline substrate for acetylcholine synthesis.
No specific avoidances listed.
Dosing & bioavailability
Where to buy
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Third-party testedIndependently verified Vitamin B1 (Thiamine) — look for USP, NSF, or Informed Sport seals on the label for purity and dose accuracy.Vitamin B1 (Thiamine) third party tested NSF
CapsulesPre-measured Vitamin B1 (Thiamine) capsules — easiest for travel and consistent daily dosing without scoops or scales.Vitamin B1 (Thiamine) capsules
PowderBulk unflavored Vitamin B1 (Thiamine) powder — best cost-per-gram and flexible dosing for stacking or mixing into drinks.Vitamin B1 (Thiamine) powder unflavored
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Vitamin B1 (Thiamine): pharmacology, clinical evidence, and safety — narrative review
Examine.com Research Team
Curated narrative review of human and preclinical evidence for Vitamin B1 (Thiamine), including mechanism, typical dosing, and safety considerations.
Best-supported outcome: Treats/prevents Wernicke-Korsakoff (evidence: strong). Additional outcomes and limitations summarized in the full profile.
PubMed: Vitamin B1 (Thiamine) — Treats/prevents Wernicke-Korsakoff
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PubMed: Vitamin B1 (Thiamine) — Benfotiamine reduces diabetic neuropathy symptoms
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PubMed: Vitamin B1 (Thiamine) — randomized controlled trial
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PubMed: Vitamin B1 (Thiamine) — meta-analysis
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PubMed: Vitamin B1 (Thiamine) — pharmacokinetics
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PubMed: Vitamin B1 (Thiamine) — safety adverse events
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PubMed: Vitamin B1 (Thiamine) — dose response
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Google Scholar: Vitamin B1 (Thiamine) — clinical evidence
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Cross-database citation index for Vitamin B1 (Thiamine) as it relates to "clinical evidence".
Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.