INS and polycystic ovary syndrome: The current study demonstrated that compared with 1000 IU/day of vitamin D and placebo, supplementation with 4000 IU/day of vitamin D for 12 weeks to PCOS women resulted in significant decreases in serum insulin, HOMA-IR, serum total testosterone levels, FAI and hirsutism, and a significant increase in SHBG, but did not influence DHEAS.