Published in 2008 this six-week, double blind, placebo-controlled, phase-III-study recruited 165 patients with symmetrical, distal diabetic polyneuropathy. Authors found a dose dependent improvement in the neuropathic symptom scores with the benfotiamine treatment group.
Stracke, H., Gaus, W., Achenbach, U., Federlin, K., & Bretzel, R. G. (2008). Benfotiamine in diabetic polyneuropathy (BENDIP): results of a randomised, double blind, placebo-controlled clinical study. Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association, 116(10), 600–605. https://doi.org/10.1055/s-2008-1065351