Background: The impact of testosterone (T) treatment on antidoping detection tests in female-to-male (F2M) transgender men is unknown. We investigated urine and serum sex steroid and luteinizing hormone (LH) profiles in T-treated F2M men to determine whether and, if so, how they differed from hypogonadal and healthy control men.
Method: Healthy transgender (n = 23) and hypogonadal (n = 24) men aged 18 to 50 years treated with 1000 mg injectable T undecanoate provided trough urine and blood samples and an additional earlier postinjection sample (n = 21). Healthy control men (n = 20) provided a single blood and urine sample. Steroids were measured by mass spectrometry-based methods in urine and serum, LH by immunoassay, and uridine 5'-diphospho-glucuronosyltransferase 2B17 genotype by polymerase chain reaction.
Results: Urine LH, human chorionic gonadotropin, T, epitestosterone (EpiT), androsterone (A), etiocholanolone (Etio), A/Etio ratio, dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), and 5α,3α- and 5β,3α-androstanediols did not differ between groups or by time since last T injection. Urine T/EpiT ratio was <4 in all controls and 12/68 (18%) samples from T-treated men, but there was no difference between T-treated groups. Serum estradiol, estrone, and DHEA were higher in transgender men, and serum T and DHT were higher in earlier compared with trough blood samples, but serum LH, follicle-stimulating hormone, and 3α- and 3β,5α-diols did not differ between groups.
Conclusion: Urine antidoping detection tests in T-treated transgender men can be interpreted like those of T-treated hypogonadal men and are unaffected by time since last T dose. Serum steroids are more sensitive to detect exogenous T administration early but not later after the last T dose.