Background: Whey proteins are widely used by adult male gym-goers as a muscle-building supplement to improve their physical appearance. Objectives: The current study aimed to investigate the impact of this practice on fertility capacity. Subjects and Methods: Forty adult male gym-goers, recruited during the period between August 2016 and April 2017, received whey protein supplementation (Gold Standard 100% Whey^TM, 15 gram daily) during their gym training for 12 weeks. Body mass index (BMI), lean body mass, semen analysis and hormonal profile (FSH, LH, PRL, T and oestrogen) were evaluated at the beginning and the end of the study. Results: A total of 33 participants completed the study. There were significant increases in mean BMI, mean lean body mass, and mean progressively motile sperms. Changes in semen volume, sperm count and hormonal levels were all non-significant. Conclusion: Whey protein supplementations did not have any negative impact on fertility capacity. Further larger and randomized controlled trials are needed to confirm these results.