Finding a metabolite in hair can add information, but its biological origin does not automatically establish how it entered the hair. A study of 63 deceased people examined para-hydroxy-methylamphetamine alongside methylamphetamine and amphetamine. The authors described the hydroxylated metabolite as a potential marker with reservations, rather than a validated answer to postmortem contamination.
What material was studied?
Mantinieks and colleagues analyzed hair from coronial cases with methylamphetamine detected in femoral blood. The paper appeared online in 2024 and in the 2025 volume of Drug Testing and Analysis. This was an analytical validation and selected autopsy-case application, not controlled dosing of living volunteers.
Hair segments nearest the root were standardized to no more than three centimeters, washed sequentially with dichloromethane and water, then extracted for liquid chromatography–tandem mass spectrometry. Of the 63 cases, 23 involved decomposition, 39 had normal body condition and one involved trauma. Washes were separately classified as clean or visibly soiled.
What did the assay add?
The lower quantification limits were 0.01 ng/mg for methylamphetamine and amphetamine and 0.001 ng/mg for para-hydroxy-methylamphetamine. These are hair-mass units. They should not be compared directly with a blood result reported per milliliter.
Para-hydroxy-methylamphetamine was quantified in 62 hair samples, with a median of 0.020 ng/mg and range of 0.0012–0.38 ng/mg. The very low concentrations explain why analytical sensitivity matters. Detection establishes what the assay measured; it does not, by itself, establish the route of incorporation.
The table’s denominators also varied by analyte and concentration range. Twelve methylamphetamine hair results exceeded the upper quantification limit. Its reported median among quantifiable values should not silently be treated as though all 63 results fell within the validated numerical range.
Why does postmortem contamination remain possible?
Hair collected after death may contact blood, sweat or decomposition fluids containing parent drugs and metabolites. Material coming from the person’s own body can be external to the hair shaft. It may reflect exposure somewhere in the organism without proving incorporation into growing hair over a particular earlier period.
The study found wash-to-hair patterns consistent with contamination, especially among visibly soiled samples. Hair concentrations of the hydroxylated metabolite were higher in the soiled group. Strong correlations among analytes did not establish that every analyte entered exclusively during hair growth.
Did bleaching settle the question?
The researchers also examined a limited bleaching experiment involving three case samples and fortified hair. Parent methamphetamine and amphetamine declined in the treated case hair. Small increases in the hydroxylated metabolite in two cases could have reflected analytical variation.
The methamphetamine-fortified hair did not produce detectable amphetamine or para-hydroxy-methylamphetamine under the tested bleaching conditions. That null finding matters: the paper should not be cited as proving that routine bleaching always creates the metabolite. The authors called for further work under realistic conditions.
What remains unvalidated?
The wash-residue analysis was not itself part of the method validation, and the authors acknowledged uncertainty about decontamination effectiveness. The cohort consisted of selected drug-related deaths, so its concentration distribution was not representative of living users.
For case review, the metabolite result belongs beside specimen condition, wash appearance, analytical limits, treatment history and other toxicology. This study did not establish a standalone hair threshold that distinguishes ingestion from every source of contamination, reconstructs a dose, or proves tolerance or impairment.
Source
Mantinieks D, Drummer OH, Schumann J, Gerostamoulos D. The analysis of methylamphetamine and para-hydroxy-methylamphetamine in post-mortem hair samples using liquid chromatography–tandem mass spectrometry. Drug Testing and Analysis. 2025;17:544–554; online 2024. doi:10.1002/dta.3765.
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