The International Tennis Integrity Agency (ITIA) today confirms that Japanese tennis player Kaili Demi Teso has been suspended for 10 months following a breach of the Tennis Anti-Doping Programme (TADP).
An independent tribunal issued a ruling of No Significant Fault or Negligence in the case of 19-year-old Teso, who tested positive for the prohibited substance methylephedrine, a stimulant which was listed on a bottle of over-the-counter cough medicine consumed by the player.
The ITIA sent the player a pre-charge notice of an Anti-Doping Rule Violation (ADRV) on 6 December 2024 under Article 2.1 of the TADP (presence of a Prohibited Substance in a Player’s Sample) and/or Article 2.2 (Use of a Prohibited Substance without a valid Therapeutic Use Exemption (TUE)).
Teso, who reached a career-high world singles ranking of 1243 in June 2025, provided an in-competition sample while competing in an ITF World Tennis Tour event in Mysuru, India, in October 2024.
The sample was split into A and B samples and the subsequent analysis found both samples contained the substance, which is prohibited under the TADP, in the category of Stimulants (section S6.B of the 2024 World Anti-Doping Agency Prohibited List).
Teso did not possess a valid TUE for the substance. Specified Substances do not require a mandatory provisional suspension, and so the player continued to compete while a full investigation took place.
Following interviews and correspondence with the ITIA, Teso asserted that the positive sample resulted from consumption of the Japanese cough medicine Shin Lulu A Gold s.
Teso’s mother, who also fulfils the role of manager, acquired the medicine on the player’s behalf. Although Teso represents Japan, the player’s first language is English, and therefore she could not read or understand the ingredients on the label, which listed methylephedrine in Japanese script.
The ITIA accepted that the violation was not intentional. While Teso admitted the ADRV, the player disputed the ITIA’s proposed sanction of 12 months calculated in line with similar cases. As such, the case was referred to an independent tribunal chair to determine the appropriate sanction.
A hearing was held via video conference on 16 June 2025, from which the independent tribunal issued a ruling of No Significant Fault or Negligence and a 10-month suspension, noting that the player’s mother had consulted a professional from a reputable pharmacy before purchasing, and that Teso, who was 18 at the time of the positive test, was inexperienced.
However, it was also noted by the tribunal that the player had received recent education on anti-doping and the risk associated with over-the-counter medications, and that, given the medication was purchased in advance of the event, there were a number of additional steps the player could have taken to reduce the risk.
Results, prize money and ranking points from the event in which the player tested positive are forfeited, but no further events are disqualified.
As the player did not elect to enter into a voluntary provisional suspension, their period of ineligibility is effective from the date of the written decision, 7 August 2025, and will end on 6 June 2026.
During the period of ineligibility, Teso is prohibited from playing in, coaching at, or attending any tennis event authorised or sanctioned by the members of the ITIA (ATP, ITF, WTA, Tennis Australia, Fédération Française de Tennis, Wimbledon and USTA) or any national association.
The ITIA is an independent body established by its tennis members to promote, encourage, enhance, and safeguard the integrity of their professional tennis events.
To read the decision in full, click here.
Ends
Published 15 August 2025 13:00
