Thiamine
Also known as: Vitamin B1, Thiamine Hydrochloride, Benfotiamine, Thiamine Mononitrate
Effective Dosage
No established universal dose; varies widely by condition and form
What the Science Says
Thiamine (Vitamin B1) is an essential water-soluble vitamin that your body cannot make on its own. It acts as a key coenzyme in energy metabolism, helping cells convert carbohydrates into usable fuel, and is especially critical for brain and nerve function. Severe deficiency causes life-threatening conditions like Wernicke's encephalopathy and beriberi; supplementation is well-established for treating and preventing these in high-risk groups such as people with alcohol use disorder, bariatric surgery patients, those on hemodialysis, and critically ill ICU patients. One retrospective study found thiamine supplementation was associated with significantly lower 30-day mortality in ICU patients with sepsis-associated delirium.
What It Doesn't Do
Won't meaningfully improve neuropathy in diabetics — a 12-month benfotiamine RCT showed no significant effect on nerve fiber measures. Not a proven standalone pain treatment — the B-vitamin pain trial combined it with B6 and B12, so thiamine alone gets no credit. No solid evidence it builds muscle, boosts energy in healthy people, or prevents aging. A small pilot study on bone health showed a reduction in one resorption marker, but this is far too preliminary to call it a bone supplement.
Evidence-Based Benefits
Thiamine is essential for carbohydrate metabolism and plays a crucial role in energy production. It is also important for proper nerve function and may help improve cognitive function in individuals with thiamine deficiency.
Strong EvidenceEffective at: 1.1-1.2 mg daily
Source: auto-research
Absorption & Bioavailability
Moderate — standard thiamine is water-soluble and absorbed in the small intestine, but absorption is limited at high doses. Benfotiamine (fat-soluble form) achieves higher blood concentrations, confirmed in the BOND study pharmacokinetics, but higher blood levels did not translate to better clinical outcomes in diabetic neuropathy. Hemodialysis patients lose thiamine during dialysis sessions, requiring ongoing supplementation.
Red Flags to Watch For
- Several common medications can deplete thiamine, including furosemide, metformin, metronidazole, and fluorouracil — patients on these drugs should discuss monitoring with their doctor
- Bariatric surgery patients face elevated thiamine deficiency risk due to altered absorption; deficiency can cause irreversible brain damage if untreated
- Wernicke's encephalopathy (a thiamine-deficiency emergency) often presents without the classic triad of symptoms — atypical presentations are frequently missed and delayed treatment causes permanent harm
- Hemodialysis patients are at high risk of recurrent deficiency and may need continuous supplementation to prevent neurological relapse
- High-dose thiamine supplements (e.g., 300 mg twice daily benfotiamine) showed no benefit over placebo for diabetic neuropathy in a 12-month RCT — more is not always better
Products Containing Thiamine
See how Thiamine is used in these analyzed products:
Augustinus Bader The Hair Revitalizing Complex
Supplement
Emma
Supplement
Alka-Seltzer Energy Boost Tropical Punch
Supplement
Flyby Recovery Capsules
Supplement
Jarrow Formulas B-Right®
Supplement
First Day Kids Daily Enrichment Multi Vitamins
Supplement
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06