Polycystic ovarian syndrome (PCOS) is a heterogeneous, persistent endocrine disease that is generally identified in 6-10% of women of reproductive age. Intriguingly, about 55-65% of patients with PCOS display insulin resistance (IR), which can be related to their body weight, ethnicity, or age. Discovering the root cause of PCOS is of particular concern due to IR and abnormal androgen secretion, and continuous attempts have been made to define the complex pathogenic network underlying the syndrome. In addition, PCOS reflects connections between various proteins, genes, and epigenetics affected by environmental influences. Genetic factors such as mutation, epigenetics, and/or expression in noncoding RNAs, particularly miRNA222, play an important role in PCOS pathophysiology and cannot be neglected. Metformin has been used traditionally as a pillar of PCOS treatment, but even effective insulin sensitization therapy can contribute to side effects that reduce patient adherence and limit treatment effectiveness. Therefore, many of the PCOS characteristics can be taken into account for the impact on hyperinsulinemic ovaries which is important in order to develop treatment strategies. Thus our primary objective is to research the therapeutic efficacy of vitamin D in the suppression of miR222 and, secondary to miR222, mediated molecular pathways involving insulin resistance and metabolic defects, which influence ovarian activity, anovula-tion, and finally infertility.