Last updated: September 25, 2023
If you’re looking at a drug test in the near future and popped in here hoping to confirm something you read online saying you’ve got nothing to worry about—you’re about to be disappointed. Because the answer is no. You aren’t going to pass a marijuana hair test if you’ve smoked, eaten, or otherwise ingested pot within the past ninety days.
There is one exception to the rule though. If you smoked—or munched—marijuana for the very first time within a couple of days of taking a drug test, it will be negative. That’s because the drug metabolites left in the body disperse themselves throughout it to await excretion. The majority store themselves in the fat cells, but some of them find their way to the hair follicle.
Marijuana metabolites that find their way to the hair follicle actually grow out into the center of the hair shaft. They become a part of the hair itself—that’s the case with any drug metabolite, by the way.
They’re there forever.
A marijuana hair test identifies the drug for ninety days. No matter what length a person’s hair is when the drug testing technician cuts the test sample, lab techs more than likely cut it again. They only use one and one-half inches of hair for the test. It’s taken from the end cut closest to the scalp.
A human’s hair grows approximately one-half inch a month. So, one and a half inches of hair identifies 90 days of drug use. We will note here that that’s the case with any drug panel added to the test. It’s not specific to marijuana.
Real-life data is racking up
The hair follicle drug test is the most expensive employee drug test on the market.
Still, employers who are looking for frequent drug use are switching to the hair follicle drug test. It does more than identify drugs in the hair. It identifies each and every instance of drug use.
In fact, some trucking companies have their drivers take a hair test in addition to the urinalysis required for the DOT drug test. They report that it has made a difference in the number of positive drug tests within the company because when applicants learn they will be required to take the hair follicle test, they don’t continue the interview!
Case in point, we found a list of trucking companies that don’t require the hair follicle test! That’s saying something, isn’t it?
Taking desperate measures won’t pay off
If you did come to this site hoping to discover you don’t need to worry about a marijuana hair test, we’re going to bust another bubble before we go.
If you’ve been reading up on tried and true methods to beat the test…
They don’t work.
You can’t shave your head and skip the test.
First of all, most people don’t rock bald as their normal look and it might look more than a little suspicious if you showed up that way on the day of the drug test. Moreover, hair doesn’t just grow on our heads, so…
Second-hand smoke might leave THC in your hair
If you’ve recently been around a lot—as in Cheech and Chong levels of a lot—of pot smoke, it could be possible for a marijuana hair test to pick it up. However, the level is extremely low compared to someone who actually smokes it.
You can’t wash the THC out of your hair
The shampoos advertised to do that don’t work.
And, please, don’t try the Macujo Method. We fear you may show up for the drug test with a dazed look in your eyes and locks of fried hair in your hands.
Sound advice for passing a drug test
People have been trying to “beat” drug tests since employers started requiring them. Back in the early days of drug testing, the only available method was the urine drug test. Some people were able to dilute their urine and fool the test—for a while, anyway.
Thanks to continued advances in technology and the increasing sophistication of laboratory equipment, that’s no longer the case. Moreover, employers now have affordable alternatives with the hair follicle drug test and the saliva—also known as the oral fluids—drug test.
Employers want to provide the safest working environment possible for their employees. They drug test for safety’s sake. Employees who use drugs get into accidents far more often than employees who don’t. They go to the doctor more frequently too.
The only way to be sure that you won’t have drugs identified in your system is to live a drug-free lifestyle.
You don’t need drugs or alcohol to make life better. It will have the opposite effect eventually. That’s a fact you don’t want to realize from experience.
Trust us on that.