Thiamine (Vitamin B1)
In 42% of hangover products, and in almost none of them is it doing anything. Genuinely vital for people who drink heavily and chronically — irrelevant to a single rough morning.
Split the grade by use. For preventing Wernicke's encephalopathy in chronic heavy drinkers, the evidence is strong and the stakes are high — this is real medicine. For improving how you feel the morning after a single night out, there is no evidence and no mechanism, since a night's drinking does not deplete stores that take weeks to run down.
Thiamine is a cofactor for glucose metabolism, and alcohol interferes with it at every step: it reduces absorption, impairs storage, and increases excretion. In chronic heavy drinking, thiamine depletion causes Wernicke's encephalopathy — confusion, ataxia, eye-movement abnormalities — which is a medical emergency, is under-diagnosed, and is why every emergency department gives thiamine to alcohol-dependent patients. That is a serious, well-evidenced use. It is also completely different from what hangover products imply. A single night's drinking does not deplete thiamine stores, which last weeks; taking B1 the morning after a party corrects nothing, because nothing was depleted. It appears in 42% of hangover products because it is cheap, safe, sounds scientific, and lets a label say 'replenishes what alcohol depletes'. The honest position: if you drink heavily and regularly, thiamine is one of the few supplements here with a real indication and you should be taking it daily, not on hangover mornings. If you drink occasionally, it is inert.
Key studies
- The alcohol hangover product market of the United States (Verster et al., 2025) — Where the 42% comes from — thiamine is one of the most common ingredients across the 46 products surveyed, alongside DHM, B12 and sodium. The same paper concludes no product in the category has demonstrated efficacy.
- Form
- Thiamine HCl is standard and fine. Benfotiamine is a fat-soluble derivative with better tissue penetration, used mainly in diabetic neuropathy.
- Dose
- 1.1–1.2 mg/day is the RDA. For regular heavy drinking, 100 mg/day is the usual prophylactic dose. For hangover specifically, no dose does anything.
- Timing
- With food, daily. Not an acute intervention.
- Schedule
- Daily if indicated by drinking pattern — the point is stores, not a single dose.
- Side effects
- Essentially none. Water-soluble, excess is excreted.
- Interactions
- None significant.
- Contraindications
- None at oral doses.
- Lab markers
- Erythrocyte transketolase activity or whole-blood thiamine if there is genuine clinical concern. Rarely measured; usually treated empirically because treatment is harmless and the deficiency isn't.
- Food sources
- Pork, sunflower seeds, legumes, fortified grains, nutritional yeast.
Pairs with
A B-complex if you're drinking heavily and regularly, since the same pattern depletes folate and B12 too. Magnesium — thiamine-dependent enzymes need it as a cofactor, and it's commonly low in heavy drinkers.
within Vitamins