Detection Windows Are Pharmacokinetics, Not Guesses

What Most People Get Wrong About Detection Testing

• Detection windows are estimates based on published literature and vary between individuals.
• Individual variation in metabolism, body fat percentage, dose, and duration of use significantly affects clearance rates.
• New testing methods are constantly being developed. IRMS sensitivity has increased substantially since 2015.
• Anti-doping agencies can store samples and retest them years later with newer, more sensitive technology.
• The Athlete Biological Passport (ABP) tracks longitudinal changes. A return to baseline after an abnormal reading is itself a flag for investigation.
• 19-nortestosterone metabolites (nandrolone, trenbolone) are among the longest-detecting compounds, sometimes persisting for over a year.
• Turinabol long-term metabolites have been detected in stored samples over four years after cessation of use.
• IRMS testing can distinguish exogenous from endogenous testosterone by carbon isotope ratio (13C/12C), even months after last administration.
• Hair analysis can detect use over a much longer period (months to years) but is less commonly employed.
• Diuretic use is itself a banned substance and triggers automatic investigation regardless of other findings.