INS and vitamin D deficiency: Similarly, a randomized, placebo-controlled, double-blind trial on women suffering from polycystic ovarian syndrome (PCOS) with vitamin D deficiency demonstrated no significant changes in the fasting serum insulin and FBG levels and the HOMA-IR index after supplementation with 50,000 IU oral vitamin D3 once every 20 days for two (2) months [70].