Thiamine (vitamin B1)

About Thiamine (vitamin B1)

A water-soluble B vitamin required for carbohydrate metabolism and nerve function, sold as thiamine hydrochloride or mononitrate. It is the vitamin whose absence causes beriberi and, in alcohol dependence, Wernicke encephalopathy.

Thiamine is a genuine medical intervention in specific circumstances and an unnecessary purchase in most others. Deficiency is uncommon in populations eating fortified grains but concentrated in identifiable groups: heavy alcohol use, after bariatric surgery, in prolonged vomiting including hyperemesis, in refeeding after starvation, and with long-term loop diuretic use. In those groups, prompt thiamine matters enormously — Wernicke encephalopathy is a neurological emergency where delay causes permanent memory damage. Outside them, supplementation on an adequate intake has no demonstrated effect on energy, mood or anything else, despite being sold for all three.

Sold as

Tablet, Capsule, High-dose tablet, Injectable (medical use), Component of B-complex

Also known as

Thiamin, Vitamin B1, Thiamine hydrochloride, Thiamine mononitrate

Regulation: No Tolerable Upper Intake Level has been established — the IOM found no reliable evidence of toxicity from oral thiamine, and surplus is excreted in urine. Injectable thiamine is a prescription medicine used for suspected Wernicke encephalopathy.

What the research used

The amounts, forms and durations published trials of Thiamine (vitamin B1) actually administered.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

In the food catalogue

The whole-food form, where one exists. The evidence for a concentrated extract rarely transfers to the food, or the other way round — these are cross-links, not equivalents.