Positive Test at ITF Event
During the ITF World Tennis Tour M15 tournament in Kayseri, Turkey, on October 2, 2025, an in-competition anti-doping test returned a positive result for clostebol—a prohibited substance classified as an Anabolic Androgenic Steroid.
The International Tennis Integrity Agency (ITIA) confirmed that the samples belonged to Juan Sebastián Domínguez Collado, a 23-year-old Guatemalan player who had recently reached a career-high ATP ranking of World No. 1660.
Confirmation of the Violation
- The A sample detected a banned clostebol metabolite, triggering standard anti-doping procedures.
- The B sample analysis confirmed the finding, formally establishing the presence of clostebol in the player’s system.
Under the World Anti-Doping Agency (WADA) Prohibited List, clostebol is categorized as a non-Specified substance, meaning violations involving it are treated with heightened severity.
Domínguez Collado did not possess a valid Therapeutic Use Exemption (TUE), leading to the mandatory imposition of a provisional suspension.
Comparison to the Jannik Sinner Case
Clostebol is the same substance involved in Jannik Sinner’s high-profile case following the 2024 Indian Wells tournament.
- Sinner tested positive twice, though in trace amounts.
- The ITIA initially ruled the presence unintentional, clearing him of fault or negligence.
- WADA later appealed, reopening the case and exposing Sinner to a potential one- to two-year suspension.
- To resolve the matter, Sinner accepted a three-month suspension, bringing the case to a close.
Provisional Suspension Details
Domínguez Collado’s provisional suspension took effect on November 19, 2025, the same day the ITIA issued a pre-charge notice alleging violations of:
- Article 2.1 – Presence of a prohibited substance in a player’s sample
- Article 2.2 – Use or attempted use of a prohibited substance or method
These provisions fall under the Tennis Anti-Doping Programme (TADP).
While the player has the right to challenge the provisional suspension before an independent tribunal chair, he has not exercised this option to date.
Consequences and Restrictions
As a result of the suspension, Domínguez Collado is barred from all professional tennis activities, including:
- Competing in tournaments
- Coaching or training
- Attending events sanctioned by ITIA member organizations
These organizations include the ATP, WTA, ITF, the four Grand Slam tournaments, and all affiliated national tennis associations.
The restrictions will remain in force until the disciplinary process is fully concluded.
ITIA Statement
The ITIA emphasized that the proceedings align with its mandate to uphold fairness, transparency, and integrity in professional tennis, ensuring that all players are subject to the same anti-doping standards.
