James Roney from the University of California, Santa Barbara, and his colleagues from Australia, Poland, and the United States conducted an observational study and concluded that day-to-day dynamics of testosterone levels are not associated with sexual desire and related activities in healthy men. The study involved 41 men of different ethnic backgrounds, aged 18 to 26 years (median 20.17 years), with normal function of the gonads. At the beginning of the study, 27 of them were not in a stable relationship, three reported a non-heterosexual orientation. The article was published in the journal Proceedings of the Royal Society B.
Over the course of 31 days, participants provided saliva samples for testosterone levels and completed questionnaires on sexual desire, fantasies, courtship, and other sexually-oriented behaviors (a total of 759 observations for the main analysis). Statistical analysis of the data was performed using multilevel regression models. No significant associations were found between testosterone levels on a given day and the strength of sexual desire or actions taken. The only correlation with testosterone production that could not be completely excluded was the subjective frequency of courtship attempts on days when a single participant had direct social contact with a potential sexual partner.