Metformin vs myoinositol: which is better in obese polycystic ovary syndrome patients? A randomized controlled crossover study

Context: Due to the central role of metabolic abnormalities in the pathophysiology of polycystic ovary syndrome (PCOS), insulin sensitizing agents have been proposed as a feasible treatment option. Objective: To investigate which is the more effective between metformin and myoinositol (MYO) on hormonal, clinical and metabolic parameters in obese patients with PCOS. Study design: Crossover randomized controlled study. Patients: Thirty-four PCOS obese women (age: 25·62 ± 4·7 years; BMI: 32·55 ± 5·67 kg/m2) were randomized to receive metformin (850 mg twice a day) or MYO (1000 mg twice a day) for 6 months. After a 3 month washout, the same subjects received the other compound for the following 6 months. Measurements: Ultrasonographic pelvic examinations, hirsutism score, anthropometric and menstrual pattern evaluation, hormonal profile assays, oral glucose tolerance test (OGTT) and lipid profile at baseline and after 6 months of treatment were performed. Results: Both metformin and MYO significantly reduced the insulin response to OGTT and improved insulin sensitivity. Metformin significantly decreased body weight and improved menstrual pattern and Ferriman–Gallwey score. Metformin treatment was also associated with a significant decrease in LH and oestradiol levels, androgens and anti-müllerian hormone levels. None of these clinical and hormonal changes were observed during MYO administration. Conclusions: Both treatments improved the glyco-insulinaemic features of obese PCOS patients, but only metformin seems to exert a beneficial effect on the endocrine and clinical features of the syndrome.