LONDON, August 15, 2025 (ITIA Press Release)
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.
