Hydrochlorothiazide remains a key focus in global anti-doping efforts
July 22, 2025Hydrochlorothiazide (HCTZ), a diuretic classified as a masking agent, has been linked to 287 doping sanctions worldwide, making it the second most sanctioned substance of its kind, after furosemide. Data from the Anti-Doping Database shows the substance remains prominent across a broad range of sports and countries.
Of the 287 sanctions recorded for hydrochlorothiazide, 87 led to two-year suspensions and 46 to four-year bans. Another 48 athletes received shorter penalties, including public warnings, six-month bans or suspensions of one year or less. The substance is listed under WADA’s S5 category and is often associated with efforts to conceal the use of performance-enhancing drugs.
In-competition use dominates
Testing data shows that 84 percent of hydrochlorothiazide cases were detected in competition. Out of 287 sanctions, 241 followed in-competition tests, while only 46 resulted from out-of-competition sampling. This trend suggests that the drug is often used shortly before events, possibly to meet weight-class requirements or to mask other agents.
Czech Republic tops national statistics
Athletes from the Czech Republic account for the highest number of hydrochlorothiazide-related sanctions, with 34 confirmed cases. Brazil and the United States follow with 32 and 25 cases respectively. Russia (24), South Africa (21), and China (14) are also among the top ten.
In the Czech Republic alone, hydrochlorothiazide is the seventh most common substance linked to doping violations, following testosterone, clenbuterol, methandienone and other known performance-enhancing drugs.
Bodybuilding and athletics most affected
Bodybuilding accounts for 68 of the 287 sanctions involving hydrochlorothiazide, or nearly 24 percent. Track and field follows with 36 cases, ahead of weightlifting (15), powerlifting (15), and swimming (13). The data indicates that the substance is most prevalent in sports where weight manipulation and physique presentation play a role.
In the Czech Republic, more than 60 percent of HCTZ sanctions were linked to bodybuilding. Other affected disciplines include tennis, volleyball, equestrian sports and boxing.
Health risks linked to misuse
Hydrochlorothiazide is widely prescribed for hypertension and fluid retention, but misuse can lead to dehydration, electrolyte imbalance and kidney stress. In sport, its primary doping-related use is either for rapid weight loss or as a masking agent to cover other substances.
With its 287 doping cases, out of over 14.000, hydrochlorothiazide has been involved in 2% of all global doping cases tracked by the Anti-Doping Database.