Concerns about serum androgens monitoring during testosterone replacement treatments in hypogonadal male athletes: a pilot study

Introduction: A well-tailored testosterone replacement treatment (TRT) in male hypogonadal athletes plays a pivotal role to restore physiological performances, to reduce health risks, and to guarantee the ethic of competition. Few studies evaluated individual androgens profiles during TRT in trained individuals.

Aim: The aim of this article was to verify the efficacy in restoring eugonadal serum and urinary androgens profiles after testosterone enanthate (TE) and gel (TG) administration.

Methods: Ten male Caucasian-trained volunteers affected by severe hypotestosteronemia (<8 nmol/L) were included. Serum androgens and urinary testosterone metabolites were evaluated, in the same subjects, before and weekly for 5 weeks after both a single intramuscular TE injection (250 mg) and during a daily administration of TG (50 mg/die of testosterone), respectively.

Main outcome measures: The main outcome measures of this article were serum total testosterone (TT), dihydrotestosterone (DHT), calculated free and bioavailable testosterone (cFT, cBioT), 17-β-estradiol, and urinary glucuronide testosterone metabolites.

Results: Supraphysiological TT concentrations were observed in 50% of our volunteers until 7 days after TE and in the 4% of total samples after TG. Serum DHT was high both after TE (all volunteers on day 7 and 50% on day 14) and during TG (32% of total samples). A relatively low number of samples showed normal cFT and cBioT both after TE and TG (20-44%, respectively). Urinary metabolites were related to the type of treatment and to serum androgens profile and resulted in the normal ranges from 15% to 60% of total samples.

Conclusion: Besides well-known variations of mean serum TT, we showed a high percentage of serum and urinary samples with abnormal androgens, being TG safer than TE. We conclude that monitoring TRT with TT only may be inaccurate because of abnormal fluctuations of other circulating androgens. Further studies to identify the appropriate markers of eugonadism during TRT are highly warranted both in athletes and in non-athletes.