Yesterday’s Explainer column at Slate answered the question, “Was Britney’s Hair Full of Drugs?” Meaning did she cut her hair to avoid a drug test. Which I totally didn’t get at first. I was picturing little baggies of powder on her head. Seriously.
It was a long day. Anyway.
They explain how you can tell someone’s drug history by chemical analysis of their hair.
Narcotics like cocaine, meth, ecstasy, and PCP introduce toxins to the bloodstream that are then incorporated into each hair as it forms in the follicle. Urine and blood only retain evidence of these toxins for a week or so, but hair can hold on to them indefinitely. (When administered correctly, hair tests are about as accurate as urinalysis.)
Head hair grows about half an inch every month, so a woman with shoulder-length hair carries around a two-year record of her drug use.
Also, any hair that grows on your body contains this information.
Drug tests can be done on any body hair—armpit, leg, back, pubic—but head hair is preferred because of its length and relative cleanliness. Although pubic hair may be long enough to provide a few months’ worth of information, it is less reliable because of its likely contamination from sweat and urine.
All I’ll say is that I prefer my women with not more than two week’s history.
P.S. It’s interesting to read, but it’s more entertaining to listen to June Thomas read it. What is that accent anyway? Something British, I presume, but where exactly?