IGFBP1 and hyperinsulinism: Given the high importance of insulin resistance and compensatory hyperinsulinemia in the management of PCOS [108, 109], a study on the different forms of fasting, including intermittent fasting and periodic fasting, showed the significant decrease of IGF-1, IGFBP1, glucose and insulin levels, and consequently beneficial effects on ovarian function, androgen excess, and infertility in PCOS women [109].