Context: Polycystic ovary syndrome (PCOS) is characterized by ovarian dysfunction and hyperandrogenism; it is also associated with increased cardiovascular risks such as adverse lipid profile and endothelial dysfunction. Metformin and, more recently, statins have been shown to improve endocrine and metabolic aspects of PCOS.

Objective: The aim of the study was to compare effects of simvastatin and metformin on PCOS.

Design: In a prospective trial, women with PCOS (n = 136) were randomized to simvastatin (S), metformin (M), or simvastatin plus metformin (SM) groups. Evaluations were performed at baseline and after 3 months.

Setting: The study was conducted at an academic medical center.

Primary Outcome: The change of serum total testosterone was measured.

Results: The study was completed by 113 subjects. Total testosterone decreased significantly and comparably in all groups: by 17.1, 13.6, and 15.1%, respectively, in the S, M, and SM groups. Significant decreases were also observed in all groups with respect to body mass index, C-reactive protein, and soluble vascular cell adhesion molecule-1. DHEAS declined significantly only in the S group. None of the treatments were associated with significant changes in LH or FSH. Total cholesterol and low-density lipoprotein cholesterol significantly declined only in S and SM groups.

Conclusions: Simvastatin treatment was superior to metformin alone, whereas a combination of simvastatin and metformin was not significantly superior to simvastatin alone.