← The FormularyLong gameThiamin
Also known as Vitamin B1The first vitamin, and still the one alcohol takes.
Thiamin is a nutrient with a dramatic deficiency and an undramatic supplement. Severe shortfall causes beriberi and, in heavy drinkers, Wernicke's encephalopathy — a genuine medical emergency, because alcohol both depletes thiamin and blocks its absorption. That history is why B-complex products exist. What it does not support is the everyday sell: in a person eating ordinary food, extra thiamin does nothing for energy, and the 33% of a day's requirement in RESET or SHIFT is there for completeness, not as an active ingredient.
The first substance ever identified as a vitamin, isolated from rice husks while people were trying to work out why polished rice caused beriberi.
Thiamin is the coenzyme for the enzymes that feed carbohydrate into the citric acid cycle. No thiamin, no conversion — which is why deficiency hits the tissues that run hardest on glucose first, and why the classic deficiency diseases are neurological and cardiac rather than digestive.
Required to convert carbohydrate into usable energy, and to maintain normal nerve and heart function.
Anyone with heavy alcohol use, malabsorption or a very restricted diet, under medical guidance. For everyone else, food covers it.
Daily, inside the B-complex. It is water-soluble; timing does not matter much.
Nothing, unless you were deficient. Correcting real deficiency is a medical event, not a supplement one.
Grade A as an essential nutrient. No tolerable upper limit has been set for oral thiamin because no adverse effect has been established. Supplementation in replete adults has not been shown to improve energy, mood or performance.
Read the labelNo established upper limit — excess is excreted. Persistent tiredness is not a thiamin question without a reason to suspect one. Heavy alcohol use is such a reason, and a medical conversation.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.