Here’s How Long Cannabis Can Be Detected in Your Body

Even with the recent wave of cannabis legalization across the U.S., there are still many reasons that a cannabis user might want to know how long tetrahydrocannabinol (THC) lingers in their body’s system. Unfortunately, the answer is far from simple.

As a baseline, THC detection times range anywhere from three days to three months after cannabis use. Whether or not a drug test will catch THC in your system depends on a number of factors: what test you’re taking, whether you’re an occasional or chronic (heavy or daily) user, your age, your gender, your body mass index (BMI), your water and fat distribution, your metabolism, and even how often you exercise. With that being said, let’s dive into the specifics of THC detection to give you a better idea of what you can expect if a drug test is in your future.

1. How Long Can THC Be Detected in Your System?
   1. Blood
   2. Urine
   3. Saliva
   4. Hair
2. How Do Drug Tests Work?
3. Other Contributing Factors
4. Can You Make THC Leave the Body Faster?
5. Final Takeaway

How Long Can THC Be Detected in Your System?

The most common types of cannabis tests you’ll encounter are blood, urine, saliva, and hair.

Blood

Blood tests have the narrowest detection window of the most common drug tests and are incredibly expensive, which makes them too impractical and inefficient for most situations. For that reason, blood tests are not something you are likely to encounter. On the off-chance that you are given a blood test, however, you should know that THC is detectable for the following amounts of time after consumption:

• Infrequent users: 1-2 days
• Regular users: 1-2 days
• Heavy users: up to 7 days

Urine

Urine drug tests are the most common method of THC detection. This is due to their long detection window, attributed to the way that cannabis metabolites bind to fat molecules in the body before they’re excreted through urine, as well as their relative inexpensiveness. With that in mind, here are the detection windows you can expect for urine tests:

• Infrequent users: 1-3 days
• Regular users: 7-21 days
• Heavy users: 30+ days

Saliva

Thanks to being cheap and easy to administer, saliva tests are common in many workplaces. They are done by placing a swab between the lower cheek and gum to gather up a sample of oral fluid. These tests are designed to detect cannabis metabolites that stick to saliva after cannabis has been smoked or ingested. Saliva tests can detect THC over the following time periods:

• Infrequent users: 24 hours
• Regular users: 30 hours
• Heavy users: 72 hours

Hair

Hair follicle drug tests have the longest detection window of the most common test types. This is because cannabis reaches hair follicles through small blood vessels and remains there well after consumption—even for very infrequent users. Unfortunately, hair tests are also notoriously inaccurate, occasionally giving false positives to individuals who have been exposed to secondhand cannabis smoke.

A 4-centimeter sample of hair cut at the scalp will detect cannabis exposure for up to 90 days in frequent and occasional users alike.

How Do Drug Tests Work?

In order to understand how drug tests work, you first need to know about the process by which THC metabolizes in the body.

Upon consumption, THC in cannabis is absorbed into the bloodstream. This happens within minutes if cannabis is smoked and in about 1-1.5 hours if it is consumed via oral ingestion. After entering the blood, THC metabolites travel around the body before making their way into tissue in the brain, heart, body fat, and elsewhere.

Cannabis tests work by detecting the presence of THC and other cannabinoids in your system. Because THC dissipates at different rates in different parts of the body, the timeframe in which an individual can test positive will largely depend on the drug test they are given.

Other Contributing Factors

There is no universally applicable answer to how long THC will stay in a person’s body. This is because there are a number of different factors that impact the duration that THC will linger in the body.

Some of these factors have to do with the cannabis itself, such as the method of consumption (vaping, edibles, etc.), frequency of use, and the amount of THC in the cannabis being consumed. Chronic users and those consuming cannabis with higher levels of THC can expect the substance to stay in their bodies longer than others who consume infrequently or opt for low THC doses. Consumption method-wise, THC is broken down quickly when smoked, while cannabis in edible form takes much longer to leave the body.

The other major factors that dictate how long THC stays in the body have to do with the weight and body type of the user. More specifically, because THC from cannabis is stored in the body’s fatty tissue, those with higher fat percentages can expect THC to stay in their bodies much longer than someone with a lower fat percentage. Beyond that, a person’s metabolism—the rate at which one’s body converts food into energy—will also have a major impact on the duration that THC remains in their system.

Can You Make THC Leave the Body Faster?

The only real way to get THC completely out of your system is to stop smoking cannabis for an extended period of time. This is why tolerance breaks help users pare down the amount of cannabis they need to get high. However, there are plenty of other things you can do to rid your body of THC more quickly.

Staying hydrated, exercising, and eating healthy are all ways that you can keep your metabolism running at optimal levels to get the THC out of your system. Making sure you’re eating a good amount of fiber is also important, as 65% of cannabis leaves the body through bowel movements.

Don’t be fooled by “detox kits” that make hefty claims about their THC-removing properties. To date, none of these products have received the seal of approval from medical professionals. In fact, a 2011 study found that vitamin B detox kits were causing their users to develop liver problems and other negative side effects, and there is little to no evidence that they actually work.

Final Takeaway

Drug tests are serious business—take it from this doctor and this commercial driver who shared their turbulent stories about testing positive for THC. And while cannabis advocates are fighting tooth and nail for more just cannabis testing policies both in the law and the workplace, cannabis consumers must protect themselves by remaining vigilant.

The length of time that THC can be detected in your system can range anywhere from three days to three months after consumption. Knowing what type of test you’ll be taking will help narrow down that detection window, but you’ll still need to consider a number of individual factors to nail down the most accurate range for your situation. These include your frequency of use, the THC potency of your products, and your chosen method(s) of consumption. You’ll also want to consider things like your height, weight, age, sex, BMI, metabolism, and exercise regimen.

Once you’ve narrowed your detection window, you can begin taking steps to prepare for your upcoming test by making sure you get plenty of sleep, food, and water to keep your metabolism at peak performance. Still have some questions about THC and drug screening? Book a consultation with a cannabis coach to learn more about how your cannabis consumption habits are impacting you.

This blog post was originally written by Lo and published on 8/12/19. Updated 7/15/22.