Potential detection of low-dose transdermal testosterone administration in blood, urine, and saliva

Administration of low amounts of endogenous hormones – so‐called micro‐dosages – are supposed to represent a major challenge in doping analysis. To model such a situation, we have studied transdermal administrations of 2.4 mg/24 h testosterone patches and examined various steroid concentrations in blood, urine, and saliva of 11 volunteers. Multiple samples were collected at t = 0, 3, 6, 9, 24, 48, and 72 h in four different phases, i.e., all combinations with/without physical exercise and with/without testosterone. Testosterone was analyzed by enzyme‐linked‐immuno‐assay as well as by mass spectrometry and validated in an accredited anti‐doping laboratory. Circadian controls with and without exercise did not provoke prominent alterations of whole, free, and salivary testosterone. Testosterone application for 24 h led to a significant (all p 0.538, all p