Thiamine (B1)
The B vitamin whose deficiency causes beriberi and Wernicke's encephalopathy. Cheap, unglamorous, and the deficiency is far more common in specific groups than most people assume.
How Thiamine (B1) actually works
Thiamine pyrophosphate is the coenzyme for pyruvate dehydrogenase, the gateway enzyme converting pyruvate into acetyl-CoA and therefore the entry point from glycolysis into the TCA cycle. It also serves alpha-ketoglutarate dehydrogenase inside the cycle and transketolase in the pentose phosphate pathway. Block that gateway and the cell cannot use glucose aerobically, which is why deficiency hits the brain and heart — the two tissues with the least metabolic slack — first and hardest.
Thiamine (B1) quick facts
| Suggested dose | RDA is ~1.1–1.2 mg. Therapeutic use ranges 100–300 mg. Benfotiamine is the fat-soluble derivative with better tissue penetration. |
| How often | Daily |
| Who it's for | Anyone on long-term loop diuretics, metformin, post-bariatric, or with a history of heavy drinking. |
✅ Clinically validated
- Corrects deficiency, which is the main and undisputed use.
- Deficiency is well documented in alcohol use disorder, after bariatric surgery, in heart failure treated with loop diuretics, and with chronic metformin use.
- High-dose thiamine trials for fatigue in IBD and Hashimoto's report benefit in small, mostly uncontrolled studies.
📊 Correlative data
- Among the best-documented deficiency epidemiology in nutrition: beriberi in polished-rice populations, and Wernicke-Korsakoff in chronic alcohol use. Both established the requirement long before the vitamin was isolated.
🧪 Theoretical / extrapolated benefits
- Thiamine pyrophosphate is the cofactor for pyruvate dehydrogenase — without it, glucose cannot enter the Krebs cycle, which is why deficiency presents as an energy and neurological problem simultaneously.
These tiers tell you how much human evidence exists — not how well something works. This is the research space, and most of what’s in here is new rather than disproven. Something sitting at “theoretical” usually means nobody has funded the trial, not that the trial was run and failed.
The trap runs the other way too: something can be clinically validated and still do very little for you specifically. A statistically significant result in a study population is not a promise about your body.
- ✅ Clinically validated — human randomised trials or meta-analyses support it. The strongest footing available.
- 📊 Correlative — observational or epidemiological data. Suggestive, and genuinely useful for direction, but it cannot establish cause.
- 🧪 Theoretical / mechanistic — the mechanism is understood and often demonstrated in cells or animals, and the human trial doesn’t exist yet. Unproven is not the same as ineffective. Plenty of what’s standard practice today sat here five years ago.
✗ is a safety flag, not a grade. Where you see it, the concern is harm — not a disappointing trial. A compound tested for one purpose and found not to help there can still be worth studying somewhere else, so a negative result never gets rendered as a cross. It sits alongside the tier, because something can be both well-studied and genuinely risky.
My job is to tell you which one you’re looking at, and let you make the call. Grading something low isn’t me dismissing it — it’s me refusing to oversell it. This is the research space, and being able to reason forward from a mechanism matters as much as waiting for the trial.
Deficiency is far more common than people assume, and the causes are ordinary: alcohol impairs both absorption and activation, loop diuretics increase urinary loss, and bariatric surgery removes the absorption site. Untreated it causes Wernicke's encephalopathy, which produces permanent damage and is trivially preventable. Anyone drinking heavily or on long-term furosemide should have this on their list. Water-soluble and very safe.
Thiamine (B1) — safety & side effects
- Very well tolerated; no established upper limit for oral use.
- High-dose thiamine given to a malnourished person can precipitate refeeding syndrome — this is a hospital concern rather than a supplement one, but it is why thiamine repletion in alcohol dependence is done medically.
- Rare allergic reactions to injectable forms; oral is not associated with this.
Not medical advice. If you take prescription medication or have a diagnosed condition, check this against it with a pharmacist or doctor — pharmacists are underused and free.
Where to get Thiamine (B1)
Find Thiamine (B1) on iHerb →Get the complete breakdown for Thiamine (B1) — inside the Academy alongside the full interactive Vault.
Unlock in the Academy — $10/mo →- When to take it, and what to take it with
- Which form actually absorbs
- Who it's worth it for
- Coach Cam's stacks and notes
Get the complete breakdown for Thiamine (B1) — inside the Academy alongside the full interactive Vault.
Unlock in the Academy — $10/mo →Bloodwork to run alongside Thiamine (B1)
Run these before you start, and again after 8–12 weeks. A baseline you didn’t take is one you can never go back for.
| Marker | What it’s watching for |
|---|---|
| Vitamin D (25-Hydroxy) | The one most often actually low, and the one with a real ceiling |
| Vitamin B12 | Commonly low in older adults, vegetarians and metformin users |
| Folate, Serum | Read alongside B12 — supplementing one can mask the other |
| Homocysteine | The functional read on whether your B vitamins are working |
The Full Micronutrient Screen panel covers these in one order — 11 markers, $363.60 with the discount applied.
Check results you already have → · All 102 markers A–Z
Thiamine (B1) — frequently asked questions
What is Thiamine (B1)?
The B vitamin whose deficiency causes beriberi and Wernicke's encephalopathy. Cheap, unglamorous, and the deficiency is far more common in specific groups than most people assume.
What is the suggested dose of Thiamine (B1)?
RDA is ~1.1–1.2 mg. Therapeutic use ranges 100–300 mg. Benfotiamine is the fat-soluble derivative with better tissue penetration. This is a general reference for education only — statements have not been evaluated by the FDA and this is not medical advice.
Where can I find Thiamine (B1) dosing and the full breakdown?
The suggested dose and the full evidence — clinical, correlative and theoretical — are on this page. What's inside the Academy is when to take it, which form actually absorbs, the brand worth buying and Coach Cam's stacks.
Where can I buy Thiamine (B1)?
Coach Cam sources Thiamine (B1) from vetted, top-rated brands on iHerb — use the buy link on this page.
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The full Supplement Vault — 350 products across 14 categories with clinical, correlative & theoretical evidence, plus my Thorne partner links — lives inside the Academy alongside 237 peptides.
Join the Academy — $10/mo →What Thiamine (B1) is used for
Thiamine (B1) appears under 2 goals in the Vault’s goal router, grouped by the mechanism it works through rather than by how much trial evidence exists. Each link opens that pathway in full, with the alternatives beside it and the bloodwork that tests it.