Although developed for medical use in the 1970s, trimetazidine was only added to the World Anti-Doping Agency (WADA) list of prohibited substances in 2014 under the category of "hormone and metabolic modulators."[6][7] Its use is prohibited at all times, both in and out of competition.[8]
In 2014, Chinese Olympic swimmer Sun Yang tested positive for trimetazidine, four months after it had been added to the banned list. He was suspended for three months by the Chinese Swimming Association.[9] Later that year, WADA reclassified trimetazidine from a "stimulant" to a "modulator of cardiac metabolism."[10][11]
In 2018, U.S. swimmer Madisyn Cox tested positive for trimetazidine and was initially suspended for two years. Testing later confirmed contamination of her multivitamins, and the Court of Arbitration for Sport reduced her suspension to six months, which expired in September 2018.[12][13]
In 2021, 23 Chinese swimmers tested positive for trimetazidine in cases reported to WADA by the China Anti-Doping Agency. Following review in June and July 2021, WADA concluded that the threshold to open an investigation had not been met. The United States Anti-Doping Agency (USADA) had raised concerns in 2020 and again in 2023 about possible cover-ups, but these allegations were deemed unsubstantiated.[14]
In February 2022, the medal ceremony for the Olympic figure skating team event, scheduled for 8 February, was delayed after what International Olympic Committee (IOC) spokesperson Mark Adams described as a matter requiring "legal consultation" with the International Skating Union (ISU).[15] Media reports later revealed the issue concerned a positive December 2021 test for trimetazidine by Russian skater Kamila Valieva,[16][17] which was publicly disclosed on 11 February.[18] Valieva was cleared by the Russian Anti-Doping Agency (RUSADA) on 9 February, but the IOC, WADA, and ISU appealed the decision.[19] On 14 February, the Court of Arbitration for Sport ruled that Valieva could compete in the women's singles, citing her age and the potential for "irreparable harm," though her team-event gold medal remained under review.[20][21]
Lawrence Cherono, winner of several major marathons, tested positive for trimetazidine and was suspended one day before the 2022 World Athletics Championships.[24]
In September 2024, Iga Swiatek, then the world's top-ranked women's tennis player, tested positive for trimetazidine and received a one-month provisional suspension after accepting a ruling of "No Significant Fault or Negligence," linked to a contaminated melatonin supplement.[25] WADA later announced it would not pursue the case further, describing the explanation as "plausible".[26]
Scientific criticism
Popular Science published an overview of scientific research about the potential for the use of trimetazidine as a performance enhancing drug for athletes. The author of the article concluded in its headline that "there's no hard proof that it would improve a figure skater's performance". Scott Powers, a physiologist at the University of Florida who studies the effects of exercise on the heart explained how trimetazidine was included in WADA list. "I've been involved in roundtables with the International Olympic Committee, and I think their policy is: When in doubt, ban the drug," says Scott Powers. "I guess they're just trying to err on the possibility that this drug may be an ergogenic aid."[27] Doping expert Klaas Faber referred to "grossly inconsistent anti-doping rules" in Sun Yang's case. Faber has pointed out for years the necessity to establish thresholds for trimetazidine detected so as to avoid any inadvertent positive doping cases. Faber has detailed some of these observations published in the journal Science & Justice.[28][11]
On the efficacy of the drug on figure skating and Valieva in particular, heart expert Benjamin J. Levine, a professor of exercise science at the University of Texas Southwestern Medical School
