Furosemide: The most sanctioned masking agent in sport

The Anti-Doping Database has registered 515 confirmed doping cases involving furosemide. That makes it the most frequently sanctioned masking agent in global sport — and the tenth most sanctioned substance overall, behind high-profile names like stanozolol, methandienone and erythropoietin.

Furosemide, marketed as Lasix, is a loop diuretic used medically to treat fluid retention and heart failure. In the context of sport, it is misused to reduce weight quickly or to mask the presence of other prohibited substances. Added to the World Anti-Doping Agency’s Prohibited List ahead of the 1988 Seoul Olympics, furosemide has remained a consistent presence in global sanction statistics.

Furosemide alone accounts for nearly twice as many sanctions as hydrochlorothiazide, the second most used masking agent with 279 cases. Others in the same category — including canrenone, amiloride and probenecid — appear far less frequently.

The numbers confirm furosemide’s position as the undisputed number one masking agent on record.

Two-thirds of all cases lead to long suspensions

Sanctions for furosemide are not treated lightly. Among the 515 cases, 259 resulted in two-year suspensions — exactly 50.3 percent. An additional 106 athletes, or 20.6 percent, received four-year bans. In total, more than 70 percent of all violations led to suspensions of two years or longer.

Public warnings or short-term suspensions are rare, indicating that anti-doping authorities interpret the presence of furosemide as a serious and often intentional offence.

30 percent of cases come from three countries

Russia, India and Kazakhstan account for a combined 160 cases — roughly 31 percent of the global total. Russia alone has 76 confirmed violations, followed by 52 in India and 32 in Kazakhstan.

These are not scattered outliers. The numbers point to consistent patterns in certain regions.

Weight-sensitive sports dominate usage

The sports most affected are those where weight, appearance or rapid recovery are central. Wrestling leads with 65 cases, followed by bodybuilding (54), boxing (50), track and field (42), and powerlifting (40). Together, these five sports account for more than half of all known furosemide violations.

The motivation is rarely direct performance enhancement. Instead, it’s often about making weight, meeting aesthetic requirements or masking other substances.

Nearly 10 percent caught out-of-competition

Forty-nine of the 515 cases were detected out-of-competition — a rate of 9.5 percent. This is higher than average for many banned substances and supports the interpretation that furosemide is used with timing and intent. 

Recent data confirms continued misuse

Since 2020, 107 new furosemide-related violations have been recorded. Russia, India and Mexico have been the most frequently involved countries in this period. Powerlifting, boxing and athletics remain the most represented sports. From 2022 alone, 57 new cases have been registered, and more than 60 percent of those resulted in two-year suspensions.

Furosemide does not boost strength, speed or endurance. But its role in manipulating weight and test outcomes makes it one of the most misused substances in modern sport. Decades after it was banned, it continues to appear — and continues to result in long bans.

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