<p>Arsenic-mediated male reprotoxicosis has emerged as a serious health concern. Arsenic-induced oxidative stress is known to impair sperm quality, cause erectile dysfunction, and lead to infertility. On the other hand, a formulated high-protein diet (FHPD) enriched with casein and pea is considered to possess significant antioxidant potential. The present study aimed to investigate the protective efficacy of such a protein-rich diet against arsenic-induced epididymal and spermatozoal dysfunctions. Adult male rats were randomly divided into three groups (n = 8 per group). Group I served as control and was maintained on a normal diet; Group II received arsenic (As₂O₃) at 3&#xa0;mg/kg/day with the same diet; Group III was treated with arsenic and supplemented with an isocaloric FHPD for 30 consecutive days. Cauda epididymal histology, oxidative stress markers, ROS generation in spermatozoa, DNA damage, and apoptosis indicators in cauda and spermatozoa were assessed. FHPD protected against histological alterations in the cauda epididymis and restored redox homeostasis by reducing malondialdehyde and protein carbonyl levels, while increasing GSH content. Activities of antioxidant enzymes including SOD, catalase, and GST were normalized, along with Nrf2 levels. FHPD significantly reduced spermatozoal ROS production. DNA damage and apoptotic changes in both cauda and spermatozoa were mitigated, as evidenced by modulation in the expression of Bax, Bcl-2, caspase-9, and caspase-3. The prevalence of apoptotic spermatozoa also decreased following FHPD supplementation. These findings indicate that the antioxidant properties of FHPD offer significant protection against arsenic-induced reproductive toxicity, thereby preserving normal reproductive function.</p> Graphical abstract <p></p>