INS and polycystic ovary syndrome: Apart from PCOS, the close relationship between acne and IR is also highlighted by recent studies which showed that hyperglycaemic carbohydrates and insulinotropic milk/dairy products are linked to diabetes and may drive acne pathogenesis, promoting increased insulin/IGF-1 signaling and supporting also a connection between milk products, acne, and increased body mass index (BMI) [41–47].