Medically Reviewed by
Jason Crawford

Article Last Updated on January 6, 2023

Whether you’re a recreational marijuana user or a regular one, and whether you use it for winding down or for medical reasons, you must have wondered how long marijuana stays in your system.

So, let’s discuss all about THC and the effects it has on the body and shed some light on how long you can have traces of THC in your system, as well as how different types of drug tests may detect it.

How THC Behaves in the Body

Marijuana is a plant with a complex chemical composition. It contains hundreds of different types of compounds among which cannabinoids CBD (cannabidiol) and THC (tetrahydrocannabinol) are the most important active ingredients. Out of the two, THC is the primary mind-altering ingredient that produces the euphoric high associated with marijuana.

When you inhale weed by smoking or vaping, THC enters your bloodstream through your lungs, and then it’s carried to your brain and other parts of the body. It then starts interacting with the body’s endocannabinoid system by attaching to its receptors and interfering with their functions in the body.

THC mimics a neurotransmitter found in the nervous system that plays a role in feeling pleasure, memory, thinking, coordination, and time perception, and it indirectly stimulates the release of dopamine. This is how you start feeling euphoric and more relaxed, also known as being high.

These effects usually last for a few hours and once they begin subsiding, you go back to normal.

When Will You Start to Feel the Effects of Vaping?

The effects of THC when you vape are felt much faster than when you eat an edible or take a THC pill because the vapor you inhale travels into your bloodstream faster. THC starts working not long after you’ve vaped – it usually takes about 20 minutes.

Vaping is quite convenient for medical marijuana users because it provides faster pain relief and control of the temperature at which THC is released, which in turn provides different effects. Smoking weed takes just as long to feel the effects, but the smoke is much harsher on the lungs than vapor.

How Long Does It Take For THC To Leave Your System?

Here’s the thing, even though the effects of weed when you vape last for a few hours, THC will linger in your system, especially if you’re a heavy user. After consumption, your body breaks THC down into byproducts known as metabolites which stay in your system for a while. With prolonged consumption, they accumulate in your body and linger until your body eliminates them on its own. Light users will typically take less amount of time to eliminate THC after marijuana use.

There are different types of marijuana drug tests, but they all usually look for THC metabolites, THC-COOH, in particular. Let’s see how long THC stays in your system and how long different types of drug tests can detect it.

THC in Blood

Blood tests aren’t that common for testing in the workplace, but they may be used. They may also be used in cases where a double-check is necessary after a false positive test. These tests can detect both THC and THC metabolites.

Generally, THC levels can be detected in the blood for a few hours to 36 hours at most provided that you haven’t had any seconds. But for regular cannabis users, like medical users or even frequent recreational users, THC can be detected for up to a week because the metabolites would have caused a build-up.

THC in Urine

Urine tests are the most commonly used in workplaces and they detect the THC-COOH metabolite. These tests are affordable, fast, and fairly accurate, which is why they’re so widely used.

Additionally, THC metabolites are detectable in urine for quite a while after use, often a few weeks after the last use. For how long THC will be detectable for each individual person mostly depends on their weed habits – frequency of use, the strain they use, and the quantity.

After a single use of weed, THC byproducts remain detectable in urine for more or less 5 to 8 days, but for more frequent use, like a few days a week, THC can be detected in your urine 11 to 18 days after you smoked last.

Finally, if you use weed nearly every day of the week or every single day, the THC byproducts will linger for much longer in your system and will remain detectable for 33 to 48 days or even up to 65 days after you last consumed it.

THC in Saliva

Saliva drug tests are rare, but they can detect THC in your body for one hour after use. This is when THC is the most detectable. After an hour, it will still be detectable, but with normal eating and drinking, it will gradually start disappearing. However, it takes up to 2 days for it to fully disappear and be undetectable. If you’re supposed to take a saliva test, brushing your teeth and using mouthwash may help neutralize it.

THC in Hair

Hair tests are also rarely used, but they have the longest detection window out of all types, meaning they’re able to detect THC byproducts over a very long period of time and they’re very accurate. For this reason, they’re used in situations where long-term cannabis consumption needs to be confirmed. THC is deposited in the hair follicles as the hair grows, which is why it can be detected for 90 days, and there are even tests that can go back in years.

Variables That Influence How Long THC Will Stay in Your System

Of course, everyone’s bodies and lifestyles are different, and this inevitably influences the way they consume marijuana. There are certain variables that can affect how THC will be handled by your metabolism such as the following.

  • The strain you use – some strains are more potent, meaning their THC content is higher, which will naturally cause a bigger accumulation of THC byproducts in your body;
  • How frequently you use weed – as we mentioned earlier, chronic users will have THC linger longer in their system than occasional users;
  • Your sensitivity – some people are more sensitive to the effects of THC than others, their body processes it differently which means that they need less amount of THC to get high;
  • Metabolic rate – people with high metabolism tend to eliminate THC from their system faster than people with slower metabolism;
  • Body fat – THC is lipid-soluble and it gets stored in your fat cells, so people with a higher body fat content will tend to store THC for longer periods of time than people with lower body fat content.

What to Do if You Have an Upcoming Drug Test?

Well, drinking lots of fluids for hydration and abstaining from using marijuana would be a good idea. Detox kits are generally not recommended because they’re not as effective as they claim to be, so you better stick to the basics. The goal is to flush out THC from the system or at least get it to non-detectable levels.


THC is a psychotropic substance found in marijuana that produces a euphoric high. How long it will stay in the body depends on different variables, but generally frequent users will have it linger for longer than occasional users. 

Different types of drug tests have different detection times for THC byproducts. The urine drug test is the most commonly used one and is able to detect THC for up to a few weeks after use.

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.