63 citations
,
August 1996 in “Forensic Science International” Cosmetic treatments like bleaching and perming can greatly reduce opiate levels in hair, possibly leading to false-negative drug tests.
8 citations
,
October 2014 in “Journal of analytical toxicology.” Chemical hair straightening significantly reduces detectable drug levels in hair.
33 citations
,
June 1995 in “International journal of legal medicine” Environmental factors can greatly reduce drug levels in hair.
14 citations
,
January 1996 in “Journal of Forensic Sciences” Hair can absorb and transfer opiates when soaked in water, with damaged hair absorbing more.
1 citations
,
August 2006 in “International forensic science and investigation series” Hair testing is a reliable method for detecting workplace drug use when done with proper sample preparation and confirmation.