Medical and recreational cannabis use is hurtling towards mainstream status, with the state-level momentum built over the last decade or so perched at a tipping point. In fact, the next U.S. presidential election will likely see federal legalization as part of at least one party’s platform.

For those of us living in a state (or a progressive country like Canada) with some level of legalization, old fears of being “busted” for using marijuana have faded into distant memory. Even in states where cannabis use remains outlawed, enforcement often takes on a reduced priority, a sort of de facto decriminalization.

For consumers, of course, the shift is welcome, and we can expect that broader social acceptance will naturally follow. Ask yourself: Have you told your friends? Your family? Your neighbors? Your work colleagues?

Hold on! Colleagues at work? We may not be ready for that just yet. Medical marijuana laws can be tricky, with important conflicts between state and federal statutes. And while we may be fine with having to weather the disapproval of our neighbors or family, we probably don’t want to test the consequences of violating employment policies. Just as cannabis businesses face operational challenges due to conflicting federal and state laws – think banking regulations – consumers also need to pay attention to a shifting, sometimes contradictory legal landscape. One of the more ominous threats to users is the drug test.

Why drug tests?

Many businesses have used drug tests for many years, most frequently as a key pre-employment screening step. Makes sense, right? You wouldn’t want to hire a heroin addict or meth user to drive a forklift or sell cars. Some employers also administer random drug tests, generally when the job elicits security or safety concerns. Trucking companies, for example, are required to administer random drug tests to at least 10% of their drivers each year. Incident-driven drug tests may also be used during traffic stops or after an accident. More recently, some states have implemented drug testing as a condition for public assistance.

Urine samples are the most common method used to test for drugs, especially for pre-employment screening. These test for use of many drugs – not just THC – and can indicate drug use after days or even weeks of abstinence. Mouth swab tests are newer, and more appropriate for on-the-spot tests since they test for active THC. Think of these as the cannabis equivalent of a breathalyzer test. Less common tests may use blood or even hair samples.

So how do you “pass” a drug test?

In short, the surest way to pass is to abstain from using. (Sorry!) For how long depends on the type of test, as well as your usage. Consider these estimates of how long THC can be detected in your system:

– Mouth swab: up to 24 – 48 hours after last use.
– Blood and urine tests: 2 weeks to 3 months, significantly dependent on frequency and amount of cannabis use.
– Hair sample: dependent on the length of the hair sample; short scalp hairs are typically used, targeting a 90-day evaluation.

If your concern is a test for a new job, you’ve got a bit of an advantage. The application and interview process will most likely be measured in weeks, giving you time to detox. If you’re a heavy or frequent user, traces of THC will remain in your system longer, meaning that even the possibility of a new job on the horizon should trigger abstinence, or at least a significant reduction in consumption. (If it makes you feel any better, you can consider abstinence a dual investment – in your future, by securing a new job, and in your enjoyment, through a forced tolerance break.)

What about cleanses? That’s a good question, and I have only a poor answer. As you might expect, you’ll find passionate – but generally unsupported – claims by the cleanse vendor. At the same time, you’ll also find people who suggest that the only thing getting cleansed is your wallet. A cleanse probably can’t hurt your cause, especially if you take the abstinence route seriously and treat the cleanse as insurance. Certainly the opposite – foregoing abstinence and relying on a cleanse – would be foolish.

There are of course many variables, including frequency and quantity of use, your body’s metabolism, even your diet. Predicting the impact of abstinence and cleanses on test results is largely guesswork. If you’re really interested in how quickly you can get “clean,” you can purchase an inexpensive home test kit and try it yourself – with or without a cleanse.

If it’s legal, what’s the problem?

You’ve got arguments, I bet, that may sound like these: Cannabis is legal in my state; recreational marijuana is comparable to social drinking; my prescription treats a state-qualified medical condition. So why do you still have to worry about taking a drug test?

As mentioned earlier, there is a patchwork of U.S. state laws regarding both recreational and medicinal cannabis use. In some states, cannabis remains just as illegal as it was 50 years ago. Where legal for medical use, qualifying medical conditions vary dramatically. For the most part, legalization efforts so far have applied to production, distribution, sale and private consumption, without explicit workplace or patient protections. And federal law remains clear, classifying THC as a Schedule 1 drug; it’s still illegal, and you should not expect any federal sympathy.

With that in mind, there are at least eight states that do offer medical marijuana users at least some level of protection from employer discrimination. Note that these protections apply to bona fide medical users, not to recreational users.

The legal tide may be turning, even beyond these eight states. Recent court cases offer hints of a shift towards employee rights, and company human resource departments are driven to reevaluate existing policies to avoid future legal entanglements while still protecting legitimate concerns. In fact, the percentage of businesses that use pre-employment drug testing is generally diminishing. In Colorado, for example, about 62% of companies tested for drugs in 2017, a notable decline from the 2014 rate of 77%.


1: Pay attention to drug test policies – at your workplace and at potential employers.
2: Use a tolerance break and an inexpensive home test kit to judge how fast your body flushes THC.
3: Don’t rely on miracle cleanses; you can test their effectiveness with a home test kit as well.
4: Apply for a medical marijuana card if appropriate.
5: Get involved by voting for candidates with progressive cannabis views.


Featured photo by Ousa Chea on Unsplash

Jack Huxley is a real person with a fake name, a casual cannabis critic, a wanderer who doesn’t mind getting lost.