INS and polycystic ovary syndrome: In comparison, metformin, a medication commonly used to improve insulin sensitivity in women with PCOS, has been associated with an average of 1.4 cm greater decrease in waist circumference compared to control treatments (Guan et al., 2020), while no differences have been found in fs-insulin, triglycerides, and waist–hip ratio when specifically compared to lifestyle treatment (Melin et al., 2023).