Last updated : May 12, 2025
Employers are beginning to choose the hair follicle drug test more often. The main reason is that hair tests provide employers with proof of consistent drug use for 90 days before the test. It’s impossible to “fake” the results because the test subject is never out of the technician’s sight. The test can’t detect recent drug use, however, but when you’re looking at the big picture, is that even an issue?
The hair test isn’t a good choice for detecting recent drug use because it takes seven to ten days for the metabolites to grow out of the hair follicle.
The natural process
When someone ingests a drug into their body, it goes through the metabolization process just like everything else. The body absorbs what it will and processes the rest into metabolites. The metabolites make their way to different areas of the body to await excretion. The hair follicle happens to be one of those storage places.
The metabolites fuse with the hair shaft making them a permanent part of the hair itself. So, once the hair grows out of the follicle enough to be captured in the test sample, there is a record of use.
Why just 90 days then?
Human hair grows approximately one-half inch per month. The set length for a hair test is one and one-half inches. Thus, one-half inches of growth times a three-month period equals 90 days. The lab technicians cut the hair samples to proper test lengths rather than the test technicians.
No way to fake it
The hair test is considered the most non-invasive of the employee drug tests because it requires just a small amount of hair. It’s said to be about 150 hairs or so, but who’s counting? The technician finds a spot that isn’t visible to others and snips the hair as close to the scalp as possible. We already mentioned that the test subject is never out of the technician’s range of vision making it impossible to switch out a sample.
However, as far as masking use goes, there are shampoos available that claim to remove traces of drug use from the hair, but they are costly. Moreover, they don’t work. Neither do the home remedies found on the internet. Using myriads of ingredients from baking soda to specific face cleansers, it all boils down to hair abuse. As a matter of fact, some of them sound as if the drug user risks arriving for the test hair in hand after trying them.
Detecting recent abuse
The blood test is the only drug test that can detect current impairment. As far as recent drug use goes, the mouth swab test could be the “winner.” It’s capable of detecting most drugs within an hour of being ingested. Some drugs can take days to show up in urine tests.
Hair tests and recent drug use
We need to bring things back around to our original point. If the hair test can’t detect drug use for about a week after it’s used but stays in the hair permanently once it has grown from the follicle, should employers be even the least bit concerned?
As an employer, you may indeed drug test someone who had only used drugs for the very first time a few days before taking the test. Does that mean they are doomed to spiral downward into addiction while in your employ? No, it doesn’t. Moreover, what about the potential new hires… or current employees who “study” up for the test… who refrain from using drugs when expecting to get hit with a drug test?
If someone uses drugs and can finagle their way past the drug test to get—or keep—a job, they’re going to do it. Overall the hair test is capable of showing a record of drug use. Imagine that for a second. The hair test detects every drug the person has consumed over the past three months before submitting their test specimen. Moreover, you’ll know how consistently they use them.
Does that shine the light in a different direction for you?
Stop it before it starts
If you operate a drug-free workplace, you may periodically offer employee classes that focus on the dangers of drug use and addiction. If not, you should consider adding the policy to your drug-free program.
Education is the best defense we have against drug abuse. It allows people to make educated choices that can keep them from ever falling prey to the high risk of becoming addicted to drugs that overwhelm the streets on any given day. Let’s keep working toward the day when fretting over “recent drug use” isn’t even on the radar.
It’s off in the distance yet, but if we keep striving the day will come.
