Abstract Background Patients with polycystic ovarian syndrome (PCOS) are associated with known alterations in mitochondria DNA copy number (mtDNA-CN). The aim of this study is to study the change in mtDNA-CN in patients with PCOS who were treated with metformin. Methods This is a prospective cohort of patients with PCOS. who received metformin for one year. https://www.alarecre.com/Virescent-Harmony-Galaxy-A14-5G-Clear-Case-p106336/