Metformin has clear benefits for women with PCOS and should be considered for those with overweight or obesity to improve weight loss, insulin resistance and lipids, say doctors.

Their systematic review — which informed the updated guidelines released last month — provides strong evidence that the diabetes drug is superior to placebo for PCOS management, with or without lifestyle changes.

“Metformin should be considered in adult women with PCOS and BMI ≥25kg/m² for prevention of weight gain and management of weight and metabolic disorders,” the authors wrote in the European Journal of Endocrinology.

While metformin had been used off label “for decades” in those with PCOS, the Monash University–led team said the study confirmed its clear benefits and filled key knowledge gaps regarding its efficacy.