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.
20 citations
,
August 2017 in “Drug testing and analysis” Drugs localize differently in hair strands based on their properties.
14 citations
,
January 1996 in “Journal of Forensic Sciences” Hair can absorb and transfer opiates when soaked in water, with damaged hair absorbing more.