Hair Testing: Fact or Fiction?


Have you ever been asked to submit some of your hair for a drug test? Have you ever required it of an employee? If you haven’t, it may not be that unusual of a request in the days to come.

For that matter, is hair testing for real? Rumors, myths and more surround this process of drug-testing. But here’s a few interesting points to note:

1. Hair testing actually pre-dates urine testing.

2. When you ingest drugs, it goes into the hair follicle, and then into the strands themselves,

3. That is where the elements stay, pretty much forever.


How does one actually perform a hair test?

– 1.5 inches of hair, is cut from the root.

– The non-root end is discarded.

– The technician will generally cut off and discard the length beyond the first 1.5 inches.

– The1.5 inches can contain up to about three months of history.


So, what drugs exactly can be detected in the hair?

• Marijuana (THC)

• Opiates (including Heroin, Codiene, and Morphine)

• PCP (Angel Dust)

• Cocaine

• Amphetamines (including MDMA, Molly, and Ecstasy)


What if you’re bald or wear military cut?

If you don’t have hair, testing is performed on the underarm, leg, or chest, and sometimes, beards.

With that, if you don’t have hair you can’t participate in a hair drug test.


How fast does hair grow?

Hair grows at a rate of approximately .5 inches per month. So, basically, if your hair is 18 inches long, and you test the ends of the strands, then you could potentially find drugs consumed more than 3 years ago! (The ends of hair, however, aren’t generally tested. Except by police.)

New hair pushes out the old hairs. Those that have stopped growing and become dormant. When a hair is no longer growing, new drug deposits can’t access it.

It can, however, stay there 1 to 4 months, so theoretically, tests can show results going back a little further than 90 days, depending on the person.  With only 10 to 15 % of your strands generally in this phase, however, the risk is not as great.

For the record, hair testing is generally used for pre-employment and random testing but isn’t generally considered a great  option for post-accident or reasonable suspicion testing.

It may not yet be the replacement for urine testing, yet. But hair testing may soon become it’s featured partner when it comes to detecting illegal drug use nationwide.

It’s definitely on the rise, and in the demand.

If you have questions or would like more information on hair testing, give us a call. We’d love to offer a free consultation.


– Paul and the Mobile Drug Testing Nashville Team

Paul Pike | President/Owner                                                                                                                                                                                                          

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One Response to “ Hair Testing: Fact or Fiction? ”

  1. May 20, 2014

    That is very educational. Thank you for sharing Paul.

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