7 citations,
January 2019 in “Journal of Analytical Toxicology” Tramadol and THC-COOH can be detected in hair for several months after stopping use.
30 citations,
March 2012 in “Journal of Analytical Toxicology” THCCOOH levels in hair decrease from root to tip and don't match well with self-reported cannabis use.
Forensic hair analysis for drugs is now more reliable and accurate.
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.
157 citations,
April 1997 in “International journal of legal medicine” Cosmetic hair treatments like bleaching and dyeing reduce drug levels in hair samples.