Background: Curcumin and its nano-micelle form (NMC)have been shown to highly exert antioxidant effects, even leadingto reductive s tress in several tissues. Aside from its abilityto boos t antioxidant capacity, chronic and high-dose consumptionof NMC is also capable of causing reductive imbalance inthe tes ticles, oxidative DNA damage in germ and somatic cells,and consequently, a decrease in sperm count and motility. It isshown that redox balance plays an essential role in maintainingprogressive sperm mobility among the various mechanismsregulating sperm motility. Thus, in order to examine the pathophysiologyof NMC agains t sperm motility, the present s tudyaimed to inves tigate whether NMC targets the reductive balance or not?Materials and Methods: Twenty-four mature male Wis tarrats were divided into ۴ groups, including control (receivedthe same volume of solvent, orally) and ۷.۵ mg/kg, ۱۵ mg/kg,and ۳۰ mg/kg NCM-received groups (orally, n=۶/each group).Following ۴۸ days, the epididymal sperms were collected, andtotal oxidant s tatus (TOS), antioxidant capacity (TAC), Glutathione(GSH)/Glutathione disulfide (GSSG) relative ratio,catalase, and superoxide dismutase (SOD) levels, as well asMalondialdehyde (MDA) contents, were analyzed. In addition,sperm motility was compared between groups. The results weres tatis tically analyzed using one-way ANOVA and Bonferronipos t-hoc tes ts. The P<۰.۰۵ was considered a s tatis tically significantdifference.Results: The sperm motility was decreased in all NMC-receivedgroups when compared to the control rats. The NMC, ina dose-dependent manner, decreased sperm TAC and increasedTOS leading to a significant reduction in TAC/TOS ratio in allNMC-received groups (P<۰.۰۵). In contras t to decreased TACand increased MDA content, the NMC-received rats exhibited aremarkable (P<۰.۰۵) increment in the SOD and catalase levels.This situation was more evident in ۳۰ mg/kg NMC-receivedrats. Additionally, the GSH/GSSG ratio was increased in allNMC-received groups.Conclusion: In light of reduced TAC, elevated levels of SODand catalase, and a notable increment in GSH/GSSG ratio, wecan conclude that chronic and high-dose consumption of NMCresults in a reductive imbalance in the sperm. As a result ofthese biochemical alterations, high-dose NMC can adversely affectprogressive sperm motility.