GDF15 and polycystic ovary syndrome: Recent evidence establishing GDF15 as a mediator of metformin’s effects on body weight and energy balance7–9, prompted a post-hoc analysis of circulating GDF15 concentrations in adolescent girls with PCOS before, during and after randomised treatments either with a standard intervention silencing the gonadotropic axis (OC), or with a low-dose combination of generic medications targeting a reduction of ectopic fat (SPIOMET)12–14.