MedicineOTC

Vitamin B1

Vitamin B1 supplement for thiamine deficiency.

Clinical information

Common uses

treating vitamin B1 (thiamine) deficiency

Common side effects

feeling sick
diarrhoea
stomach ache

Cautions

best to avoid alcohol during deficiency treatment
children under 12 only on specialist advice

Interactions

fluorouracil (cancer medicine — affects how thiamine works)

Pregnancy: can be taken if recommended by your doctor

Reference information, not medical advice — always follow your doctor or pharmacist. Source: NHS Medicines A–Z, nhs.uk/medicines/thiamine-vitamin-b1 (accessed 2026-08-16)

Approved brands & formulations1

Brand name	Dosage form	Strength	Importer	Category
Benerva	Tablet	100 mg	authorized medicine importers	OTC