However, this “metabolic” model is biased by the assumption that PCOS pathogenesis mostly relies upon a metabolic “defect” (i.e., defective insulin transduction due to impaired availability of inositolphosphoglycans) and underestimates the steroidogenic effects directly triggered by myo-Ins and especially by D-Chiro-Ins. Here, INS is linked to polycystic ovary syndrome.