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Chances are, if you are asking something like, “How long does weed stay in your hair?” you are probably facing rigorous drug testing for a new job. While most companies opt for urine or saliva drug tests because they are more cost-effective, some industries are very serious about marijuana consumption and subject employees to hair follicle testing for THC. Some industries that are known for using hair follicle testing are the casino gaming industry, auto manufacturing, oil and gas, financial industry, and of course the transportation industry.
If you are staring down one of these tests yourself, keep this in mind: THC can be detected in your hair if you consumed cannabis two or more times in the last 3 months. If you used cannabis more than that, or if everyone at your local dispensary knows you by your first name, THC can be detected as far back as one year.
How Long Does Weed Stay In Your Hair?
If you only smoked or consumed cannabis once in the last three months, you don’t have to worry. That’s not a high enough dose of THC for it to bind to your hair and raise red flags in detection.
When you use cannabis, the THC metabolites actually bind to the structure of your hair. A hair test for THC is able to detect very small amounts of THC compared to urine and saliva tests. It is by far one of the most rigorous forms of drug testing.
To top it off, THC does not just bind to the hair on your head. It binds to all hair on your body, which means your body hair can also be used for THC hair testing.
How Does THC Get In Your Hair?
Whether you smoke, vape, eat, or lather on your cannabis, the THC will enter your bloodstream, triggering the active compounds in the plant. Once the compounds come into contact with the cannabinoid receptors in your body, you will begin to feel the effects of the cannabis. This means the compounds in cannabis actually bind to your cells and travel through your blood. The blood is then fed to the cells of the scalp, and at a point of the hair follicle called the “hair papilla.” THC is particularly good at traveling through the blood and binding to the hair at the exact point where hair growth begins. This is how hair follicle tests pick up on THC from the root of the hair.
How Do Hair Tests Work?
So when it comes to hair testing, the question is not really “How long does weed stay in your hair?” Rather, because THC binds at the point where hair begins to grow, the question is, “How fast can your hair grow?”
THC hair follicle drug tests require just a 1.5-inch sample of hair. Typically the sample is taken from the root of the hair, which is why it is so hard to beat a hair drug test. There is a bit of a myth out there that body hair grows slower than the hair on your head, so it will show a longer cannabis history, but that isn’t really true.
The hair on your body grows at the same rate as the hair on your head, but it regenerates at a different pace, which can make it more susceptible to THC metabolites. Every time a hair reaches the end of it’s growing cycle, your body will shed it and there is a time period where the hair follicle is dormant. Typically, this is one-four months. Eventually, a new hair will begin to grow in the old hair’s place. At any given time, 10-15 percent of the hair on your body is dormant, and during this time the hair follicle is the most susceptible to binding with THC metabolites.
That is basically how hair testing works. The small hair sample is tested at the follicle to see if any THC metabolites are bonded to it. The only part of hair that matters is the root – the remainder of the hair is discarded. If the hair on your head is shorter than 1.5-inches, hair can be taken from your legs, chest, and underarms. The only area where your hair cannot be taken is from your pubic area.
How Sensitive Is A Hair Test?
THC hair follicle drug testing is the most accurate form of drug testing. A hair test can detect the presence of THC metabolite in nanograpms per milliliter (ng/ml). The lowest it can detect is 1ng/ml. To give you a big of perspective, a urine or saliva test can detect between 50ng/ml to 20ng/ml.
Those numbers seem pretty intense, but if you use cannabis infrequently, the chances of testing positive for THC in a hair follicle test are very low. People who use cannabis regularly will definitely test positive for THC in a hair follicle test, and there are not many ways around it.
Weirdly enough, things like melanin content can affect a hair follicle THC test. People with darker hair and grey hair will have more sensitive results and have a higher chance of coming up with false positives.
Can You Beat A Hair Test? Yes! But It Will Cost You.
As mentioned before, it’s almost impossible to beat a hair test by detoxing if you are a frequent cannabis user. A regular detox, like the kind you might use for urine or saliva tests, will have almost no effect. And washing your hair with regular shampoo won’t do anything towards removing THC from your hair because the THC has actually bonded to the actual cells of the hair follicle. That being said, cannabis users unite! Many people attest to beating hair follicle tests using some old-school hair detox shampoos and other alternative methods.
One product that cannabis users swear by is the old formula of Aloe Toxin Rid, a detox shampoo that’s proven to remove things like THC from your hair. You can purchase the shampoo from TestClear, where it has over 72 reviews and an average rating of 5-stars. It costs about $300, but if it means keeping your job or getting a new job, it may be worth it for you. In scanning the reviews, the shampoo only works if it is used exactly as the directions state. Also, don’t fall for other clarifying shampoos – this is the one formula that many people attest to working, and make sure it contains propylene glycol.
The Macujo Method
In combination with the Aloe Toxin Rid, you also want to use something called the macujo method. For this method, you need:
- The Aloe Toxin Rid
- Another shampoo of your choice with at least 3 percent salicylic acid
- Liquid detergent (any brand)
- Heinz white vinegar
- Shower caps (10 minimum)
- Goggles (Do not skip the goggles – this combo can really burn your eyes!)
Basically, when you get your supplies together, you’ll strap on those goggles and get your hair wet with warm water. Massage tons of vinegar into your scalp and hair, then add the salicylic acid shampoo. Next, wipe off any shampoo that gets on your forehead so it doesn’t burn or cause suspicious skin irritation. Put on the shower cap and let the mixture set for 30-40 minutes. Rinse it off and immediately wash your hair with the Nexus Aloe Rid Shampoo. Follow with the detergent.
The macujo method can dry out your hair, so feel free to follow the process with conditioner to retain some of the moisture in your hair.
Home Testing Kits
If you have a bit of lead-time with your testing, consider buying an at-home hair testing kit. This will let you know how effective your hair detox has been, and will save you from some serious anxiety if you can go into the test knowing you are clean.
The Jerry G & Other Honorable Mentions
Seriously, how did people do anything before the Internet? Thanks to cannabis detox forums, there are a few other alternatives you can turn to if you cannot afford the Aloe Toxin Rid shampoo and don’t have 90 days to let the THC detox naturally. Basically, with the Jerry G method, you completely destroy your hair follicles by bleaching it with peroxide bleach and baking soda.
There is also the incredibly laughable method of shaving off all of your hair. And yes, I mean literally all of your hair – including your body hair and eyebrows. Now, if you walk into a drug testing with no hair, it is pretty suspicious and weird, and you could definitely lose out on the job opportunity just based on that. But, in the case of having no hair to test, you could be given a urine test instead, which might be easier to pass.