Caffeine, theophylline, and human sperm motility.

Concentrations of 10(-2), 10(-3), 10(-4), 10(-5), or 10(-6) M caffeine and theophylline were added to semen samples to determine the effects of these compounds on several parameters of semen quality. Semen samples were incubated at 37 degrees C and observed 0.5,1,2,4, and 6 hours after addition of the respective compounds. Semen quality was determined by estimating the percentage of active spermatozoa, by estimating sperm motility, and by counting the number of viable sperm at each time interval. Neither of the compounds, at any of the dose levels tested, had any significantly different effects on the quality of sperm motility or the percentage of active or viable spermatozoa, although a few samples responded favorably to these compounds. Noted improvements in semen quality did not appear to be dependent on the initial semen quality. The data contradict previous reports and suggest that methyl xanthines do not have beneficial effects on the majority of semen samples obtained from men seen at a fertility evaluation clinic.