Abstract Context Little is known about how exogenous testosterone (T) affects the steroid profile in women. More knowledge would give the antidoping community keys as to how to interpret tests and detect doping. Objective This work aimed to investigate the steroid profile in serum and urine in young healthy women after T administration. Methods In a randomized, double-blind, placebo-controlled study, 48 healthy young women were assigned to daily treatment with T cream (10 mg) or placebo (1:1) for 10 weeks. Urine and blood were collected before and at the end of treatment. Serum steroids were analyzed with liquid chromatography–tandem mass spectrometry, and urine levels of T, epitestosterone (E), and metabolites included in the Athlete Biological Passport (ABP) were analyzed with gas chromatography–tandem mass spectrometry. Results In serum, T and dihydrotestosterone levels increased, whereas sex hormone–binding globulin and 17-hydroxyprogesterone decreased after T treatment as compared to placebo. In urine, T and 5α-androstanediol increased in the T group. The median T increase in serum was 5.0-fold (range, 1.2-18.2) and correlated to a 2.2-fold (range, 0.4-14.4) median increase in T/E in urine (rs = 0.76). Only 2 of the 24 women receiving T reached the T/E cutoff ratio of 4, whereas when the results were added to the ABP, 6 of 15 participants showed atypically high T/E (40%). In comparison, 22/24 women in the T group increased serum T more than 99.9% of the upper confidence interval of nontreated values. Conclusion It seems that the T/E ratio is not sufficient to detect exogenous T in women. Serum total T concentrations could serve as a complementary marker of doping.