Source Naturals - Benfotiamine 150mg 120 tab. Dietary SupplementBenfotiamine is a more bioavailable derivative of thiamine (Vitamin B-1). Unlike normal thiamine, benfotiamine is fat-soluble and more physiologically active. It supports normal glucose utilization by stimulating transketolase, the ... - Source Naturals - Benfotiamine 150mg 120 tab.