How to Pass a Drug Test for Weed?

Weed test

Along with varying degrees of marijuana legalization, there emerged an industry standard of testing employees for THC levels.

This may be scary for consumers who smoke recreationally on weekends or after work during the week when they’re off the clock.

If you’re reading this, then chances are you’re in a similar nerve-wracking situation. Heading into work the next day and having to face a random drug test may have you wondering about the tests you’ll have to take.

Well, we have some answers for you. From details on urine and blood tests to tips on detox and THC consumption, we looked at some of the most common questions you may have on how to pass a drug test for weed.

However, as always, educate yourself on the matter, do your research, be smart and you should be fine.

How long does THC stay in your system?

The first issue to address, of course, is about THC: how long does THC stay in your system?

One of the main factors to consider is that THC is fat-soluble, which means that it’s stored in fat cells. In other words, it takes longer for your system to metabolize.

This spells bad news for marijuana users: cannabis can leave traces of consumption for the longest period of time. There’s no mathematical rule here, though.

THC detection in drug tests is made even more complicated by other factors. It varies and depends on things such as:

  • Frequency of consumption – Obviously, an everyday consumer used to smoking a lot of weed will have higher THC levels in his system than a person who smokes weed for the first time. So determine where you land on that spectrum.
  • How much you consume – Quantity does count. If you have a pending drug test coming up, try not to cheat with a few puffs. Instead, restrain completely from any consumption whatsoever.
  • How you consume — How THC is broken down will also determine where in your system it will be detected and hence, how long it stays in your system. Consuming edibles versus smoking a joint go through different metabolic pathways, for instance, and affect your test results accordingly.
  • Weed potency – Not all THC strains are created equal, we all know that. More concentrated doses will mean your system will have to metabolize more THC.
  • Metabolism – Your body’s mechanism of processing toxins and burning fats is an important indicator when considering your THC levels. That being said, the amount of fat you have in your body is directly connected to how much “room” there is for storing THC.
  • Lifestyle – If you have a healthy diet and exercise regularly, your metabolism has a higher and faster performance rate, which means that the body can naturally get rid of toxins much more effectively.

What’s more, different parts of your body have different detection periods, and there’s a huge difference between the types of samples that are taken for testing.

For example, your hair follicle could reveal marijuana consumption for up to 1 year, while 2-3 days would suffice to have your blood cleansed of all THC.

Here’s a table that might come in handy when estimating the possible amounts of THC in your body:

Weed test table

Natural detox

Now that you’re armed with the above timeframes, the next natural question for you is how to start flushing your system out.

If you aren’t on short notice and have a reasonable timeframe to detox, do it naturally. It’s the simplest and the least aggressive method.

Here’s what you can do immediately to start preparing for a drug test.

  • Stop smoking or vaping weed – Although it sounds obvious, try not to trick yourself into smoking, eating, or in any way consuming cannabis.
  • Drink a lot of water – Optimized hydrating will naturally “flush” THC from your body. Be cautious, though, as drinking a lot of water on the very day of your test can cause your urine to be overly diluted and raise suspicion (we’ll cover this issue later on).
  • Exercise – Getting active will boost your metabolism, and help you detox more effectively. However, be sure to stop exercising a few days before the test, as this can have the opposite effect – THC metabolite levels can increase in your body within 24 hours of exercising.
  • Eat fruits and vegetables – A diet rich in fiber, antioxidants, and vitamins can help you speed up the process. It goes without saying to avoid junk food, caffeine, sodas, and alcohol as they’ll all slow down your metabolism.

If you have enough headway, generally 4-6 weeks, your body should be able to naturally and completely detox and score positive results on your test.

Types of drug tests

As we mentioned earlier, different types of samples pose different challenges. This is where the way in which you consume cannabis will play a role.

Naturally, you’ll have greater chances for success when you know what you’re up against. Here is a look at the different drug tests you can be given:

Urine test

Of all the tests administered by employers, this is the one most commonly conducted. It’s inexpensive, the results are quite reliable, and the samples are easy to collect. Plus, THC remains detectable for a longer period of time in urine than it does elsewhere.

A urine drug test doesn’t actually trace the level of THC, but it traces its metabolites (the breakdown products of THC).

Good news is that you don’t have to be 100% clean. The typical detection threshold of metabolites for a urine test is 50 ng/ml. You just need to be below that level to pass.

Blood test

When testing your blood for marijuana, the lab will determine whether or not there are traces of actual THC in your sample – not the metabolites. The upside here is that THC is present in your blood for only 24 hours. Note though that frequent users could show positive results for up to 7 days.

This blood test method is not really popular among employers as it is expensive, doesn’t reveal much, and collecting samples for this type of test is more complicated.

Hair follicle test

Although it’s an effective testing method that can detect weed consumption for up to 3 months after use, a hair follicle test is expensive, uncommon, and generally used for highly sensitive jobs.

On the other hand, collecting a sample is quite easy – only an inch of your hair from the scalp, pubic area, arms or legs is required.

Saliva test

Along with urine testing, saliva drug tests are the most commonly used method by employers. It’s inexpensive, the samples are taken with simple swabbing, and the results are reliable.

On the downside (or upside, depending on your perspective), the metabolites of THC are detectable in saliva for only 24 hours.

Now that you know a bit about the kind of drug tests you can be given, the next step is to start thinking about how to pass a drug test. We dug up some tips and advice below.

Disclaimer: We do not promote any illegal activities. The following discussion is for educational and general information purposes only. We do not guarantee any results or outcomes based on this information and trying any of the methods is at the readers’ own risk. All readers are advised to conduct their own research and consult their physicians for expert advice.

How to pass a urine test

If you have the time to naturally detox your system, you should be fine. Be cautious with staying hydrated, though, as drinking gallons of water just before your test could over dilute your urine and generate suspicion.

In such cases, it’s suggested that you should take Vitamin B12 and B2, along with creatinine, as these will ensure that your sample has a “natural” color.

You should take slightly more than the recommended daily intake, and do so just a few hours before testing.

Bear in mind that the half-life of these supplements allow them to be visible in your urine for only a few hours, so taking them days in advance won’t help your cause.

If you want to be absolutely certain, you can get yourself a home drug testing kit to determine how much or how little can produce a negative result.

If you’re still above the detection threshold (50 ng/ml), here are some last-minute methods to ensure you pass:

  1. Specialized detox products 

There are plenty of these available on the market today. Essentially, these detox products expel the THC from your urine over a certain amount of time so you can produce a clean sample.

Detox products usually have some diluting agent and different mixtures of creatinine, Vitamin B2, and B12, so there’s no need to take the supplements with these same-day detox products. Doing so could also be potentially harmful.

In any case, be sure to do your research, consult product reviews, get in touch with reviewers and dispensary professionals.

  1. Niacin

Niacin, also known as Vitamin B3, is naturally produced in the body and plays a role in metabolizing carbohydrates.

Because of this property, it has been used to help prepare for drug tests as it increases the body’s rate of breaking down fats where THC is stored, and can help flush out one’s system.

Although people have reported that they passed a drug test with the help of niacin, it should be noted that niacin is hard on the liver and could lead to ugly side effects such as flushed skin, skin rashes and swelling. Large doses aren’t recommended.

  1. Certo or Sure-Jell method

Due to its simplicity and lack of side effects, this method is popular as a last-minute shot at passing a drug test.

Certo is a high soluble fiber. As fruit pectin, it ensures the toxins are trapped and then broken down into smaller metabolites, making it easier to expel.

All you need to do is mix a packet of Certo (or any other fruit pectin) in a 32 oz. bottle of Gatorade (some recommend cranberry juice) and drink it 3 or 4 hours before the test.

The mixture will dilute your urine, so it’s highly advisable that you take your supplements (creatinine, Vitamin B2, and B12).

Also, be sure to urinate 4 times before giving a sample, as this will help flush the toxins out of your system.

Whatever your choice, it’s important to remember a couple of things. For instance, don’t submit your morning sample as that first urine of the day is packed with toxins.

Also, be sure to catch the midstream while you urinate. For optimal results, schedule your testing somewhere around noon.

  1. Using synthetic urine

This is the only 100% fool-proof method on this list that ensures you pass a drug test. It’s also the ultimate cheat.

You can buy synthetic urine online, or ask a friend who is drug-free for a clean sample. You’ll have to make sure that your sample is the right temperature. You can microwave it for a minute, and keep it warm with some hand warmers.

However, as with all kinds of cheating, this is the hardest option to get away with, without the risk of being caught.

If you decide to go for it, bear in mind that you might be supervised while providing a sample.

Also, do know that most clinics have strict controls to prevent cheating, so be prepared to face the consequences. Have a strategy and a backup plan ready to go.

How to pass a blood test

As blood tests have a shorter detection time and take time to schedule, so you’ll most likely have the time you need to detox.

Abstain from consuming weed for 4 days if you’re a casual user, and at least 10 days if you’re a heavy user. You may experience withdrawals, but performing a natural detox program is the best way to go.

To be sure, you can always take some last-minute detox product (specialized, Certo). It will have the same cleansing effect as on urine.

How to pass a hair follicle test

This is a tough test to pass. Aside from not smoking for at least 3 months, shaving your head (which is not really an alternative method as they can always use other hairs on your body), or using bleach that can seriously harm your health, there is a method called the Macujo Method.

This is basically a medical-level hair detox process that involves using Nexus Aloe Rid shampoo, salicylic acid shampoo, vinegar, and liquid detergent. You’ll also need extra gear – eye protection (swimming goggles are ideal) and a shower cap.

Once you have everything ready, follow these steps:

  1. First, put on some protective eye gear such as swimming goggles.
  2. Dampen your hair with warm water.
  3. Next, massage a bit of vinegar into your hair and scalp.
  4. Then, without rinsing, massage the salicylic acid shampoo in (you’ll experience a burning sensation, which is normal).  
  5. Get rid of any excess shampoo and put on a shower cap for 30 to 45 minutes.
  6. After 30-35 minutes, take the cap off and thoroughly rinse.
  7. Then wash your hair with Nexus Aloe Rid Shampoo.
  8. Add detergent and rinse thoroughly.
  9. Repeat the process daily for 10 days.

How to pass a saliva test

As with all the tests mentioned earlier, it’s best to start a natural detox program to pass saliva testing. But if you are on short notice, take a last-minute detox product in a form of bubble gum or mouthwash. It will usually keep your saliva clean for the next 6 hours.

It’s interesting that if you want to donate blood, you don’t have to be “clean”. The only thing that the Canadian Blood Services and the American Red Cross require is that you’re sober enough to give informed consent to donating blood.


Always be smart and don’t harm yourself. Do your research, even if you’re working against the clock. Sometimes the test just isn’t worth the risk of hurting yourself.

About the author
Helena Miles

Experienced journalist with a decade-long experience of researching cannabis. She has been featured in many prominent outlets, such as The Growth Op, National Post and The Province.

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