Polycystic ovarian syndrome (PCOS) is a common gynecological disorder with multifactorial pathogenic risk factors. Combination therapy with metformin and thiazolidinedione derivatives is frequently used, but its synergistic effects have not been thoroughly evaluated. This study aims to compare the therapeutic efficacy of low-dose spironolactone (LDS) at 0.25 mg/kg for 28 days, metformin at 500 mg/kg for 28 days, and a combination of LDS and metformin, against a letrozole (1 mg/kg/day) and 0.5% carboxymethylcellulose (CMC)-induced PCOS rat model. The study involved five groups of laboratory animals: Group I (Healthy control), Group IIa (Disease control), Group IIb (Metformin), Group IIc (LDS), and Group IId (Metformin + LDS). Therapeutic efficacy was evaluated based on phenotypic, hormonal, and genotypic determinants. Letrozole successfully induced PCOS in the animals, evidenced by elevated levels of Sex Hormone Binding Globulin (SHBG), Follicle Stimulating Hormone (FSH), and progesterone, as well as the presence of multiple ovarian cysts. Hierarchical Cluster Analysis indicated that LDS was superior to metformin and the combination therapy in ameliorating PCOS symptoms. The findings suggest that there is little to no benefit in adding metformin to LDS for the clinical management of PCOS. Although these results are from preclinical studies, further case-controlled, randomized placebo studies on a larger patient sample are necessary to confirm these findings in clinical settings.