Benfotiamine (rINN, or S-benzoylthiamine O-monophosphate) is a synthetic, fat-soluble, S-acyl derivative of thiamine (vitamin B1) that is approved in some countries as a medication or dietary supplement to treat diabetic sensorimotor polyneuropathy.

[4] As of 2017, benfotiamine was marketed as a pharmaceutical drug in many countries under the following brand names: Benalgis, Benfogamma, Benforce, Benfotiamina, Biotamin, Biotowa, Milgamma, and Vilotram.

In one study of a combination of benfotiamine, pyridoxine, and cyanocobalamin, around 8% of people taking the drug experienced nausea, dizziness, stomach ache and weight gain.

[6] Benfotiamine is dephosphorylated to S-benzoylthiamine by ecto-alkaline phosphatases present in the intestinal mucosa, and is then hydrolyzed to thiamine by thioesterases in the liver.

[7][6][9] Benfotiamine is a lipid derivative of thiamine, specifically a synthetic S-acyl Vitamin B1 analogue; its chemical name is S-benzoylthiamine O-monophosphate.