Where the System Breaks Down
The test has a documented workaround. Dr. Oliver Barley, a researcher with a background in combat sports weight management, has publicly described helping fighters, including what he called "big names," pass ONE's hydration test while still cutting weight through dehydration. The method exploits a quirk of the urine specific gravity measurement: drinking distilled water, which contains no electrolytes, tricks the kidneys into behaving as though the body is over-hydrated. The kidneys respond by producing dilute urine, which reads as well-hydrated on the test even when the fighter's actual hydration status is compromised.
ONE has since tightened enforcement rather than redesigning the underlying test. Under a more recent rule change, any athlete who fails to pass hydration testing and make weight within the first hour of a three-hour testing window is fined 20 percent of their contracted purse, a financial deterrent layered on top of the medical one.
