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How Long Does Weed Stay In Your System?

How long does weed stay in your system?

It’s a simple question with a complicated answer.

But, it’s an answer many cannabis consumers need to know.

Despite marijuana being legal in Colorado, many locally-based companies continue to drug test potential employees. Marijuana is also included in the standard 5-panel (and often random) drug tests that occur during probation.

And if you’re visiting from out of state and wish to enjoy the local greenery, you might wonder how long you’ll test positive for marijuana once you get back from vacation.

So I set out to shed some light on this often confusing issue.

This article is NOT about how to “cheat” a drug test. I won’t be talking about fake urine or using someone else’s urine.

Instead, I want to focus on how long cannabis stays in your system (on average) and the factors that keep it in your system longer. I’ll then get into a few natural ways you can clear your system faster.

Just Tell Me How Long I’ll Test Positive for Pot

Drug-testing equipment generally tests THC levels in urine. So, let’s focus our efforts there for now.

According to data compiled by the US National Drug Court Institute,

  • Occasional or first-time users will probably test positive up to 4 days after last using.
  • Frequent users may test positive up to 10 days after last using.
  • Very heavy users could test positive for up to 1-2 months after last using, though it’s uncommon to test positive after 21 days of abstinence.

These are just estimates, however, and there are a variety of factors that could increase (or decrease) how long you will test positive for marijuana.

What about blood, hair, and saliva tests?

Saliva tests can identify marijuana use for about 24 hours in occasional users, and up to 3-7 days in very heavy smokers. Some estimates show a significantly lower period of time when you will test positive (as little as 1-12 hours).

Blood tests are less common than urine tests. Most cannabis consumers will test clean in under 30 days.

Hair tests are infrequent and often unreliable. But, they are still used by some companies and institutions. THC typically shows up in a hair drag test about 7 days after use, and you could test positive for cannabis for up to 90-days, regardless of how much cannabis you smoked (or ate).

Ok, now that we know how long marijuana stays in the average person’s system, let’s look at the key factors that influence how long pot stays in your system.

What Factors Influence How Long Marijuana Stays In Your System?

Depending on the source you look at, you could test clean in as little as a few days and as much as 11-13 weeks. This range has made it difficult for many marijuana enthusiasts to accurately estimate how long weed will stay in their system.

It’s possible to narrow that window if you know what factors affect the detection period of cannabis.


Your height, weight and build all play a role in how long cannabis stays in your system. As a general rule, the larger you are, the longer you’ll test positive for marijuana.

Activity Level

Because cannabinoids are often stored in fat cells, your activity level (and how much fat you burn) plays a direct role in how long THC will stay in your system.


A fast metabolism will help you burn through fat and clear your system faster. I offer a few tips for boosting your metabolism later in this article.

Second-Hand Smoke

Good news, everyone! You’re unlikely to test positive for marijuana, regardless of whether you’ve been exposed to second-hand cannabis smoke.

2010 study investigated cannabinoid concentrations in blood and urine for individuals exposed to second-hand smoke. In the study, eight participants were exposed to second-hand marijuana smoke in a coffee shop in Maastricht, Netherlands.

Blood and urine tests were conducted at regular intervals (both during and after exposure). And while participants did have THC in their systems, it wasn’t enough to test positive for marijuana or achieve the mythical “contact high.”

Last Time You Smoked

While a saliva test will typically show cannabis for 12-24 hours after consumption, a hair test could show any level of marijuana consumption over the past 90 days.

Regardless of testing method, the time and date of your last marijuana dose will play a role in whether or not you test positive. Your body needs time to clear cannabinoids from its system.

Frequency of Consumption

How often you consume cannabis is the biggest factor in how long weed will stay in your system. If you’re an occasional or first-time marijuana smoker, all traces of weed are likely to be out of your system within about 4 days. If, like me, you’re a heavy consumer, you could test positive for cannabis for up to 30 days (sometimes longer).

How Can You Get Marijuana Out of Your System Fast?

If you’re applying for a job that requires a drug test—or if you have random or mandatory drug tests as part of a current position or probationary period—your safest option is to stop smoking (or eating edibles)…

I wasn’t born yesterday, though. I know that isn’t going to happen for many consumers.

So, what can you do if you find out about a drug test after hitting a joint?

1. Adjust your diet

THC is stored in fat cells, where it is released into the bloodstream (and later expelled in urine). If you have a drug test coming up in a few days, one option is to significantly reduce calories—or even fast—for a few days to help the THC trapped in your fat cells escapes into the body.

Next, drink LOTS of water to help clear the THC from your system. The more you pee, the less THC you’ll see.

Finally, increase your caloric intake again and continue drinking plenty of water.

2. Increase your activity level

The more you exercise, the more fat you burn. Since THC is stored in fat cells, this is one of the surest ways to help eliminate THC from your system fast.

Combine this step with a change in your diet to help eliminate THC even faster.

3. Boost your metabolism

High metabolism helps burn fat faster and, in turn, helps expels THC that was trapped in fat cells.

But, speeding up your metabolism is easier said than done, right?

You might be surprised to learn that you can give your metabolism a boost using two simple methods.

First, switch up your exercise routine to high-intensity interval training (HIIT), which has been shown to play a role in speeding up slow metabolism.

Next, take a metabolism-boosting supplement, like selenium. Without enough selenium in your system, your body struggles to utilize thyroid hormones that control metabolism.

The question remains for many smokers: should you use a detox kit?

I actually recommend against using detox products for cannabis. It isn’t that these products can’t work (some of them, anyway), but they aren’t catchalls, and they’ll only help you avoid a positive test result during a short window.

Making detox kits even riskier is that these products are designed to dilute your urine—typically working as a diuretic. Not only can the lost water result in dehydration and other health concerns (particularly if you’re on medication), but many drug tests will show a positive result if urine appears to be tampered with or diluted.

I hope this article helps. And I invite you to comment below with your own story.

Don’t Worry, Be Happy (and High)

After conducting my own research and analyzing a variety of sources and peer-reviewed studies, the actual detection time for cannabis appears to be significantly lower for a vast majority of consumers than is often reported. This is especially true for occasional or first-time smokers, who could test clean in as little as 1-3 days.

Chances are you won’t test positive for marijuana for as long as you thought you would at the start of this article.

And that’s something to celebrate… with weed! Stop by Karing Kind in North Boulder to stock up on top-shelf, clean-grown bud and CO2 extracted cannabis oil.

Pre-Order Now

Karing Kind is located just off of US-36, one mile north of Broadway, open MON-SUN from 9am to 10pm.

While we carry a variety of strains, concentrates, edibles, salves and tinctures, inventory and stock levels fluctuate from week to week and month to month. Check our menu and follow us on Twitter for an up-to-date list of edibles, concentrates and buds available.