Objective: Recently, oral antioxidants in combined forms have been used to treat men with idiopathic infertility. This study aimed to evaluate the effects of treatment with vitamin C, vitamin E, selenium, zinc, arginine, L-carnitine, and coenzyme Q10 on sperm quality parameters, DNA integrity, reproductive hormones, and pregnancy rates in men with infertility and idiopathic oligoasthenoteratozoospermia (OAT). Methods: A prospective study was conducted on 420 men with infertility and idiopathic OAT who took an oral supplement of antioxidant SP-Power tablets twice daily for 6 months. Semen quality, reproductive hormones, and the DNA fragmentation index (DFI) were evaluated at baseline and at 3 and 6 months after supplementation, using the World Health Organization 2021 guidelines. Results: No significant difference was observed in volume or the percentage of typical morphology during treatment. A significant improvement in sperm concentration was observed after supplementation (8.67±1.41, 12.17±1.91, and 19.01±0.86 at baseline, 3, and 6 months respectively, p<0.01). The total motility, progressive motility, and total motile sperm count also increased significantly (p<0.01), whereas the DFI decreased after 6 months. There was an increase in normal FSH levels and testosterone levels after 6 months of supplementation of antioxidant SP-Power but these differences were not statistically significant (p=not significant and p=0.06, respectively). Conclusion Supplementation with SP-Power tablets improved sperm quality parameters, sperm DFI, some reproductive hormones, and pregnancy rates in men with infertility and idiopathic OAT, which could be attributed to the supplement’s synergistic antioxidant action. Further studies are needed to determine the effects of supplementation on oxidative stress markers.