Ruth Chepng’etich, the women’s marathon world record holder, has been handed a three-year suspension by the Athletics Integrity Unit (AIU) after admitting to Anti-Doping Rule Violations (ADRVs) involving the presence and use of hydrochlorothiazide (HCTZ), a banned diuretic.
The 31-year-old Kenyan athlete — a former world marathon champion and three-time Chicago Marathon winner — tested positive for HCTZ from a sample collected on March 14, 2025. Following the positive result, the AIU launched a full investigation into the circumstances surrounding the violation, which Chepng’etich later accepted along with the accompanying sanction.
HCTZ, though occasionally found as a contaminant in certain medications, is also misused by athletes to mask the presence of other prohibited substances. The World Anti-Doping Agency (WADA) sets a reporting threshold for HCTZ at 20 ng/mL, below which results should not trigger a violation. However, Chepng’etich’s urine sample showed a concentration of 3,800 ng/mL, nearly 200 times the reporting limit.
When first interviewed by AIU officials on April 16, 2025, Chepng’etich said she could not explain the presence of HCTZ in her system.
Investigators then collected detailed information about all supplements and medications she had recently used, and retained any available products for laboratory testing. Her mobile phone was also copied for digital analysis.
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At a follow-up interview on July 11, 2025, the AIU presented evidence from her phone that raised reasonable suspicion the use might have been intentional. Chepng’etich was also informed that laboratory tests on all her supplements and medications had come back negative for HCTZ. Despite this, she maintained that she had never knowingly taken a banned substance.
On July 31, 2025, Chepng’etich altered her account, admitting in writing to the AIU that she had been unwell two days before the test and had taken medication belonging to her housemaid without checking whether it contained a prohibited substance.
The AIU accepted her admission but imposed a three-year ban, underscoring the athlete’s responsibility to ensure that no banned substances enter their system.