Zerbinati C, Caponecchia L, Fiori C, et al. - This research intent to measure an isotope dilution gas chromatography-mass spectrometry method, α- and γ-tocopherol concentration in human semen in a large and well-characterized population (134 men with different semen parameters and in varicocele patients), as well as their potential role in male fertility. Researchers performed freeze/thaw experiments in 15 samples with the two isomers in the cryoprotective medium. Furthermore, this research involved 10 participants supplemented in vivo with α-tocopherol for 90 days. The outcomes of in vivo α-tocopherol supplementation indicated a reduction in γ-tocopherol concentration with an increasing α-tocopherol level in blood. This is the first report linked to γ-tocopherol distribution in human semen investigated by gas chromatography-mass spectrometry. The study suggested that γ-tocopherol would not appear to be associated with semen parameters but to cellular oxidative condition.