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How Long Does Weed Stay In Your Hair: Will You Test Positive?

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Generally, a hair follicle drug test can detect marijuana within 90 days of use. In this article, I’m going to tell you everything you need to know about hair tests, and I’ll walk you through the most popular methods to remove THC from your hair.

How Effective are Hair Follicle Drug Tests?

Very effective! As soon as THC enters the body, it’s broken down by your liver and is absorbed into the bloodstream. While THC itself doesn’t stay in your system, the metabolites can stay in your body for several weeks. They become part of your hair cells as your hair grows, and can also be present in the sweat on your scalp.

To make matters worse, you can pick up THC metabolites if someone who has handled marijuana touches your hair. You can even test positive if someone smokes near you. So, you don’t necessarily need to be using the substance to test positive.

Learn More: Here is our complete guide how to pass the hair follicle test.

Hair Testing 101: What Happens During a Drug Test?

man with rasta hair holding head

During a hair follicle test, a lab worker checks for the presence of illicit substances in your hair. To do this, they will cut anywhere between 100 to 120 strands from your head.

If you’re bald, the collector will use hair from your chest, underarm, leg, or face. If you are wearing a hairpiece, inform the person collecting samples to ensure that they get strands of your real hair (fun fact: a police officer once tested positive because of a hair weave she was wearing).

Initial Screening: ELISA

Once enough hair samples have been collected, they will be mailed to a lab for testing. They’re then washed and placed in a solution to break down their components. Afterward, lab workers add antibodies that bind to THC to detect its presence. This process is known as an enzyme-linked immunosorbent assay (ELISA) screen.

You can get a negative result from hair tests 24 hours after your sample passes the initial screening.

Secondary Test: GC/MS

If you get a non-negative result for the initial screening, the sample will be put through a gas chromatography/mass spectrometry (GC/MS) test.

This will enable the lab to conclude a positive test result and determine the substances present in your system. You can receive a positive result from hair tests within 24 hours.

Can Hair Tests Be Wrong?

As mentioned, you can get a false positive on drug tests just by being near marijuana smoke. Even rolling weed can influence the result.

Aside from these occurrences, hair color can also alter the sensitivity of the test. Dark hair is the most susceptible to testing positive. Gray hair can also return false positives, though it’s unclear why this happens.

How Long Does Weed Stay In Your Hair?

A hair test can pick up drug use for up to three months since your last use. Since hair grows at a rate of 0.5 inches per month, and samples for drug testing are taken 1.5 inches from the scalp, you have to be clean for 90 days before you’re considered safe.

Detection time can also change depending on the thoroughness of the lab that’s testing you. Some labs also take samples from longer strands of hair, so they can detect whatever was in your system up to about a year ago.

How to Test Clean On a Hair Follicle Drug Test

Hair consists of three layers: the cuticle, the medulla, and the cortex. THC is stored in the cortex, which is surrounded by the cuticle  – that’s why it can’t be washed out by regular shampoo alone.

The Secret to THC Removal: A Powerful Detox Shampoo

aloe toxin rid shampooMy recommended detox shampoo is Old Style Aloe Toxin Rid Shampoo. It contains propylene glycol, a colorless and odorless synthetic additive that belongs to the same chemical group as alcohol. This is the key to removing residual medication, environmental pollutants, chlorine, hard water minerals, and other impurities from within the hair follicle.

According to a study, tripropylene glycol works as a moisturizer, antioxidant, and emulsion stabilizer. It’s considered a safe chemical by the FDA, and is commonly found in cleansers and disinfecting gels, as well as deodorants and antiperspirants.

Old Style Aloe Toxin RId Shampoo is particularly useful for removing traces of weed because it eliminates toxins while keeping your hair follicles intact. The deep-cleaning shampoo also contains aloe vera, soybean sterol, and avocado oil, which soothe the scalp as it eliminates toxins.

How to Wash Away THC Using a Detox Shampoo

Washing off THC metabolites from your hair requires a 10-step process that you should repeat over several days. Here’s what you should do:

  1. Wear goggles to protect your eyes and rubber gloves to protect your hands.
  2. Wash your hair thoroughly with warm water.
  3. Apply Heinz vinegar to your hair to open up the hair follicles. You might feel a sting, but continue applying it into your hair until you’re sure that everything has been thoroughly cleansed.
  4. Lather salicylic acid shampoo into your hair. Use it for several minutes, making sure that all strands have been thoroughly cleansed.
  5. Wear a shower cap and leave the mixture for half an hour. The combination of products may sting, and your scalp may turn red.
  6. Wash your hair with warm water to remove the vinegar and the salicylic shampoo.
  7. Use a large amount of Old Style Aloe Toxin Rid Shampoo. Make sure all corners of your head are thoroughly washed. Leave it for 15 minutes.
  8. Wash your hair with warm water.
  9. Repeat step 7 to further strip toxins from the hair.
  10. Use a few drops of Tide detergent on your hair. This is the final step of the process.

How to Beat a Hair Follicle Drug Test


Light Smoker: Occasional smokers will need to use detox shampoo at least 3 times to pass the test.

Regular Smoker: Those who have a weekly habit will need to run through the protocol at least 7 times to ensure a pass.

Chronic User: Those who smoke weed every day need to run through the protocol a minimum of 10 times.

The Jerry G Method: Eliminate THC Through Bleaching

The Jerry G method involves using bleach to strip open the hair cuticles and expose the cortex, allowing you to remove THC from the hair. The downside is that constant bleaching destroys the strands and causes severe split ends.

Check our step-by-step guide of the Jerry G method here.

How to Remove THC From Your Hair Using Bleach

For the Jerry G method, you’ll need a detox shampoo, peroxide bleach, hair dye, and baking soda. These substances will change your hair’s texture and makeup.

  1. Wear protective gloves and goggles.
  2. Bleach your hair using peroxide, then dye it to your natural hair color.
  3. Wait 10 days. If you don’t have 10 days before your next test, do the next step the day before your hair test.
  4. Bleach and dye your hair again.
  5. On the day of your test, massage a very thick mixture of baking soda and water to your hair then wait for 15 minutes. This allows the mixture to settle and open your cuticles.
  6. Now that your hair cuticles are open, wash it with a powerful hair follicle detox shampoo.
  7. Repeat Step 4 and 5 several times.

Tips for Getting Rid of THC From Your Hair

To ensure that you get the best results, read the tips below.

TIP #1: Avoid Weed, Now!

For these methods to work, you need to stop using weed as soon as possible. You should also keep yourself from using it until after you know the result of the drug test. If the laboratory requests a re-test, you might find yourself in a pickle.

TIP#2: Sanitize Everything That Touched Weed

Wash any items that have had contact with your hair, such as your hairbrush, hats, pillowcases, and headbands. This removes the risk of reintroducing the toxins you were trying to remove.

TIP#3: Don’t Use the Same Detox Plan For A Urine Test

Instead of using a detox shampoo, some people might recommend removing THC from the body using detox drinks and supplements. While these products can be useful for cleansing your body for a urine test, they’re not particularly effective for hair drug tests.

The Bottom Line: Weed Stays in Hair for a Long, Long Time

Hair follicle tests might sound scary, but you can still beat them with the right information, a couple of effective cleansers, and a solid plan. Just make sure that you’re using a powerful detoxifying shampoo like Old Style Aloe Toxin Rid Shampoo. Once you pass the test, you’ll be wondering why you were so anxious in the first place!