Longitudinal changes in competitive performance in elite 46,XY DSD runners during prolonged testosterone suppression.

To assess longitudinal changes in the official competitive performance in elite runners with androgen-sensitive 46,XY differences of sex development (DSD) during prolonged testosterone suppression. This retrospective longitudinal study analyzed nine elite 46,XY DSD runners with 5α-reductase type 2 deficiency who maintained serum testosterone below 2.5 nmol/L after gonadectomy, gonadotropin-releasing hormone agonist treatment, or combined oral contraceptive use. Outdoor performances in sprint, middle-distance, and long-distance events were evaluated. Semester-best performances were compared with presuppression personal bests and expressed as percentage change and World Athletics World Ranking points. Before treatment, mean serum testosterone was 22.5 ± 6.5 nmol/L. Follow-up included 16 performance profiles and 44 semester-best observations over 0-1,258 days of suppression. Competitive performance declined after testosterone suppression, with mean decrements of 6.0, 7.1, 6.5, 7.2, 6.6, and 4.4% across successive semesters. Across the full observation period, the mean performance decrement was 6.5 ± 3.6%, and after 2 yr it remained approximately 6.0 ± 4.5%. No significant difference in percentage decrement was observed between sprint and middle-/long-distance groups, although substantial interindividual variability was present. Sustained testosterone suppression in elite androgen-sensitive 46,XY DSD runners was associated with a clear but heterogeneous reduction in competitive performance. In several athletes, the decrement remained smaller than the expected elite male-female performance gap, suggesting that previous male-range androgen exposure may confer advantages not uniformly abolished by current testosterone suppression.NEW & NOTEWORTHY First publication describing on the effect of testosterone suppression of androgen-sensitive differences of sex development (DSD) elite athlete and their competitive performance. Performance reduction is significant but heterogenous in magnitude and smaller than the expected and known performance gap between male and female elite athletes. Some DSD athletes showed performance reduction below 3% after 1,000 days of effective testosterone suppression. Performance reduction does not seem to be different in sprinters when compared with distance runners.