BACKGROUND: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women, associated with dyslipidemia, insulin resistance, and hormonal imbalances. Metformin and curcumin have shown promise in improving these metabolic and hormonal parameters individually, but their combined effects in PCOS remain unclear. METHODS: We conducted a randomized, double-blind, placebo-controlled, 12-week factorial trial involving 200 women with PCOS. Participants were randomly assigned in a 1:1:1:1 ratio to receive metformin (500-mg/8 h) + placebo, nanocurcumin soft gel capsule (80-mg/8 h) + placebo, metformin (500-mg/8 h) + nanocurcumin (80-mg/8 h), or double placebo. Lipid profiles, glucose metabolism markers, hormonal parameters, body weight, and body mass index (BMI) were assessed at baseline and week 12. RESULTS: The combination of metformin and curcumin demonstrated significant improvements in lipid profiles, glucose metabolism, hormonal parameters, body weight, and BMI compared to individual agents or placebo. Greater reductions in low-density lipoproteins (LDL) cholesterol, total cholesterol (TC), and triglyceride (TG) levels were observed with the combination therapy, along with increased high-density lipoproteins (HDL) cholesterol. Additionally, the combination therapy significantly improved markers of glucose metabolism and showed synergistic effects in reducing body weight and BMI. Reductions in testosterone and improvements in Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) levels were also observed with combination therapy. CONCLUSION: The combination of metformin and curcumin demonstrates superior efficacy in improving lipid profiles, glucose metabolism, hormonal parameters, body weight, and BMI in women with PCOS compared to individual agents or placebo. This highlights the potential synergistic effects of combining these agents for the management of PCOS.