The effects of 8-week creatine supplementation with and without ubiquinol on sperm quality biomarkers in normospermic and oligospermic men: A randomized controlled pilot trial

Background No studies have investigated whether dietary creatine, administered alone or in the combination with other nutrients, can induce changes in the physical-chemical and microscopic characteristics of human semen. Objectives The primary objective of this randomized placebo-controlled exploratory pilot trial was to assess the effects of an 8-week supplementation regimen consisting of creatine, both with and without ubiquinol, on sperm quality in men classified as normospermic and oligospermic. Methods A total of 15 volunteers (mean age 25.0 ± 6.1 years, body mass index 25.1 ± 2.0 kg/m²; including five oligospermic individuals) were randomly assigned, received the intended treatment, and were evaluated for spermiogram parameters, sperm biochemical markers, the World Health Organization (WHO-5) well-being index questionnaire, and the prevalence and severity of side effects. Results There was a non-significant trend towards an increase in sperm concentration among participants receiving creatine-plus-ubiquinol, with an average rise of 7.4 million per milliliter ( P = 0.22). Six out of ten participants receiving creatine (60%), both with and without ubiquinol, showed an improvement in sperm concentration at the 8-week follow-up, compared to only 20% of participants in the control group ( P ≤ 0.05). In addition, all oligospermic men who received creatine and creatine-plus-ubiquinol demonstrated an improvement in sperm concentration at follow-up, whereas sperm concentration remained unchanged or further decreased among oligospermic men in the control group ( P ≤ 0.05). Furthermore, there was a significant increase in sperm creatine concentration in the creatine-plus-ubiquinol group ( P = 0.03), demonstrating an average rise of 125.4 µmol/L (35.8%) at the 8-week follow-up. Conclusion These preliminary findings are of considerable interest for male fertility health; however, they require validation through well-designed longitudinal trials with larger sample sizes. The study is registered at ClinicalTrials.gov (NCT06202469).