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Tens of millions of people consume cannabis on a regular basis to treat hundreds of diseases and ailments, or to ease anxiety and mellow perspective resulting from lifestyle use. Unfortunately, even in states that have legalized recreational cannabis, employers and others continue to test for it, even among those who are registered medical patients living in fully legal states.

Given the value of your job and career, how confidently can you consume cannabis if you know, or even suspect, that you will have a drug test at a future date?

Technically, a drug test is simply an analysis of a biological specimen such as urine, hair, blood, breath, sweat, and saliva to determine if it contains a particular drug or one of the metabolites produced from that molecule by the human body.


Unfortunately, it is not only your current or future employer that may conduct scheduled or surprise drug tests. Health care companies, law enforcement (such as after an auto or industrial accident, even for those not at fault), and other agencies routinely require their members or customers to prove that they can test negative for cannabis, even in legal states.

How Long Does THC Stay in Your System?

The rule of thumb when it comes to smoking, vaporizing (vaping), or ingesting (eating) cannabis is to allow 30 days to pass prior to taking a urine test. However, there is a big difference between someone who consumes several grams of cannabis flowers or indulges in many dabs of concentrates on a daily basis, and another person who rarely consumes or has a couple of puffs on special occasions.

Anecdotal reports have indicated that some heavy smokers and vapers may require up to three months to rid their system of all traces of the THC cannabinoid. However, the one-time non-user described above would be most vulnerable to testing positive only for a few days following consumption. A week after smoking, this hypothetical newbie would be almost guaranteed to pass with a negative result for cannabis.

The reason the 30-day window is good advice is because everyone is different. A 260-pound 30-year-old who never exercises and has a poor diet will have a very different metabolism than a 155-pound 50-year-old who exercises on a regular basis and consumes healthy foods.

When it comes to one’s career and income, it’s not wise to take chances. Just because a friend or neighbor passed a test one week after a few puffs from a joint in no way means that you might achieve the same result.



How long prior to a drug test should you cease cannabis consumption?

Those who consume pot regularly may want to schedule a two-month hiatus to ensure that they aren’t refused a job or dismissed from one due to testing positive.

Those who are weekend tokers or smoke a few times a month — especially if it is relatively low-potency cannabis and small quantities are consumed — should be fine by quitting about a month prior to a test. Anything less is simply taking chances with the ability to get a job, pay one’s bills, or become or remain a participant in a health care plan.

CBD Users: No Worries

Those using CBD-only oils or tinctures to treat a disease such as cancer, epilepsy, or multiple sclerosis need not worry about a drug test. Because a standard five-panel urine test looks for only a single metabolite produced by THC (THC COOH), those who consume any quantity of CBD will never test positive for cannabis. Metabolites are simply chemicals produced by the body (like THC COOH) that are derived from an outside molecule (such as THC).

Test Yourself First

Some employers give new hires or veteran employees a short window in which they can self-schedule and take a drug test, often at a third-party laboratory or clinic. Those worried about testing positive can employ the services of such testing labs independently to learn if they will flag positive for pot when the real test is administered.

The problem? Learning one’s status for a five-panel urine test will cost about $60-100 in most cities. Home test kits are also available at drug stores that are significantly less expensive, but their results are sometimes inaccurate and not necessarily a good gauge of what a certified, professional laboratory will detect.

Advice for Cleaning Your System

There’s no silver bullet or magic pill to rid one’s system of the metabolites produced by consumption of THC that are detected by common urine drug tests. However, there are plenty of ways to expedite the cleansing process and help ensure the a drug test doesn’t test positive for cannabis.

First, engage in flushing. Flushing is drinking relatively large quantities of water, cranberry juice, coffee, or tea. Because all of these, with the exception of water, are natural diuretics, they help to cleanse the body of the THC COOH metabolite produced by THC.

Some regular smokers perform heavy water flushes to rid their body of the metabolite directly prior to a test. Those who choose to adopt this approach must be careful to not over-hydrate, a condition called water intoxication of which one symptom is blood that becomes too thin.


Also, those who flush heavily must ensure that their urine doesn’t become overly diluted. Because flushing is a common strategy employed by cannabis smokers undergoing drug tests, lab technicians are keen to it, disqualifying some urine samples.

Although diluted urine might not flag positive for cannabis, it will raise a red flag and at least require a retest. Beware: These retests are typically scheduled as soon as possible (same day or next day) to help prevent masking (also known as cloaking), which is the drinking of special liquid agents (sold as “pass your test” products) to mask the presence of the THC COOH metabolite.

What You Should Do Before Your Test

As for the actual taking of the test, there are a few rules: Wake early and drink plenty of water, continuing the flush. Ensure that the urine provided for the test is not the first of the day (something medical professionals call the “first void”). Intelligent consumers should get up early enough and drink enough water and cranberry juice to ensure that the urine they provide is several hours — and many urinations — removed from the first of the day.

Masking agents, which are packaged like energy drinks and feature flavors like orange and cherry, are available online and at many head shops. They are consumed a couple of hours prior to a drug test, specific instructions are provided on the label.

Readers are warned to be very careful in putting faith in such cloaking drinks. While they sometimes work (anecdotal reports from friends and colleagues are often very impressive), these masking drinks don’t always do the job. Be sure to take an at home drug test before you put all of your faith in the effectiveness of one of these drinks.

What About Hair Tests?

Sometimes, employers and other agencies forego the common five-panel urine test for a more detailed and significantly more accurate analysis of one’s hair. Such tests typically take a few strands of the most recent growth (that closest to the scalp or neck) that are at least 1.5 inches long. This gives the laboratory a 90-day window of a user’s past cannabis consumption.


An even longer detection window can be observed if a lab utilizes body hair, as opposed to that from the head, simply because it grows more slowly. There is actually a good side to hair testing: It eliminates the potential for outside contamination of a sample. However, for those who have consumed any quantity of cannabis within the past three to five months, via any method, this technical fact is of little consolation.

While the hair test has been thought to be arguably the most precise method, the findings of a recent study, published in October 2015, revealed that the hair test method may not be accurate as initially reported. The study concluded that the THC molecules do not pass proportionately from the bloodstream into hair follicles and, therefore, may lead to more false positives than other methods.

While the THC metabolite does not transfer into hair follicles proportionately from within the body, it does transfer via outside contact. This means that if a non-consumer comes in contact with the hands or sweat of a person who does consume, the molecules could transfer to the non-consumer’s hair more easily than if the non-consumer had actually smoked cannabis. Until more research is completed on this subject, the hair test method will likely continue to be used.

In Conclusion

While many regular tokers employ masking agents a couple of hours prior to a urine test, such an approach will deliver uncertain results that may give pause to many fans of cannabis.

Unfortunately, the best approach for helping guarantee that one passes a drug test is abstinence, pure and simple. It is simply the length of this abstinence that is the trick, especially for patients who suffer without cannabis medicine. Masking drinks have their place and should be considered, but only as an emergency backup.

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