Benfotiamine (S-benzyolthiamine-O-monophosphate) is a synthetic derivative of thiamin, belonging to the family of compounds known as "allithiamines." Benfotiamine is fat-soluble and thus more bioavailable and physiologically active than thiamin. Characteristic of the allithiamines is an open thiazole ring within the chemical structure of these thiamine-related compounds, making them fat (lipid) soluble. In contrast, thiamine, which is water soluble, has a closed thiazole ring. The lipid solubility of benfotiamine, conferred by this open ring, increases its bioavailablity.
