Caffeine increased progressive motility of human spermatozoa in normozoospermic and asthenozoospermic semen samples and enhanced activity of seminal creatine kinase

Even though the effect of caffeine on humans' health has been revealed in various research studies, its effect on semen quality has yet to be well explained. Here, we measured the effect of caffeine at 1, 5, 10 and 20 mM on motility of human spermatozoa in normozoospermic and asthenozoospermic semen samples, level of seminal nitric oxide, chelation of seminal calcium ions and activity of seminal creatine kinase. Fifty‐one normozoospermic and ten asthenozoospermic semen samples were recruited in this study. Sperm motility was evaluated by Makler counter, and seminal nitric oxide, seminal‐free calcium and activity of seminal creatine kinase were measured spectrophotometrically. Caffeine at 10 mM significantly (p