Background: The aim of this study was to evaluate the non-genomic action of thyroxin on sperm kinetic and its probable use to improve sperm recovery after applying an enrichment method like "swim-up" in comparison with the available one, pentoxifylline.Materials and Methods: This is an experimental study. A total of 50 patients were recruited, followed by infertility consultation. Conventional sperm assays were performed according to World Health Organization criteria-2010 (WHO-2010). A Computer Aided Semen Analysis System was employed to assess kinetic parameters and concentrations. Number of the motile sperm recovered after preparation technique was calculated.Results: Addition of T4 (0.002 mg/ml) to semen samples increased hypermotility at 20 minutes (control: 14.18±5.1% vs.17.66±8.88%, P<0.03, data expressed as mean±SD) and remained unchanged after 40 minutes. Significant differences were found in the motile sperm recovered after swim-up (control: 8.93×106±9.52×06 vs.17.20×106±21.16×106, P<0.03), achieving all of the tested samples a desirable threshold value for artificial insemination outcome, while adding pentoxifylline increased the number of recovered sperm after swim-up in 60% of the studied cases. No synergism between two treatments could be determined.Conclusion: We propose a new physiological tool to artificially improve insemination. The discussion opens windows to investigate unknown pathways involved in sperm capacitation and gives innovative arguments to better understand infertility mechanisms.