Adami LNG, et al. - Researchers conducted the study for analyzing the impacts of different concentrations of carnosine, a dipeptide composed of histidine and beta-alanine which has a significant and potent antioxidant function acting as a chelator of metal ions, added during human semen processing. Semen samples from 34 individuals have been submitted to processing by discontinuous density gradient centrifugation without (control) or with different concentrations of carnosine supplementation as follows: 20 mM of carnosine supplementation on the layers of Percoll and 50 mM carnosine supplementation. When compared with untreated samples, the 50 mM carnosine supplementation resulted in improved sperm mitochondrial activity. Motility variables like percentage of motile and progressively motile spermatozoa, average path velocity, straight line velocity, curvilinear velocity and linearity, displayed an improvement after semen processing independent of carnosine supplementation. Both carnosine concentrations raised the beat-cross frequency (BCF) relative to the preprocessing samples. In semen samples, carnosine supplementation benefits sperm mitochondrial activity and BCF.