INS and Insulin resistance: For the first time, Kotsa et al. (2009[36]) showed that the consumption of Alphacalcidol (1-a-hydroxyvitamin D3) 1 μg/day for 3 months in 15 obese women with PCOS and insulin resistance, produced an effect on the first phase insulin stimulation, indicating that vitamin D3 could be effective in the treatment of PCOS.