How Long Does Weed Stay in Your System?

If you've recently smoked, eaten, or vaporized cannabis, you may be wondering how long will it stay in your system?

Regular cannabis users will know that the effects of cannabis aren't as intense or psychoactive as other substances. However, that doesn't mean ridding your bloodstream of its influence is easy.

While the effects of cannabis fade quickly, the length of time the drug can be detected in the body for weeks, sometimes longer.

Random drug tests are commonplace in many workplaces worldwide, and the difference between passing and failing could mean severe consequences. So, if you're reading this, there's every chance you're worried about how long cannabis or THC stays can be detected.

How long depends on various factors, including:

Your BMI:

THC and THC-COOH (more on that later) metabolites are stored in the fat cells in your body, so the more significant your body fat (or BMI- Body Mass Index), the slower you'll be able to metabolize and excrete cannabis.

Your age:

As you age, your body functions begin to slow down. Some of these changes affect how THC is processed in the body. A slower digestive system and reduced liver function affect how your body processes and releases cannabis from your body.

Your gender:

Women usually metabolize THC at a slower rate since they typically have higher body fat levels than males.

Your tolerance:

First-time consumers can expect cannabis to be present in the system anywhere between three and four days, but this increases with oral consumption (like edibles). Regular users who consume cannabis can expect marijuana to be present in the system for at least a week. The more significant your marijuana use, the longer it'll be in your system, a general rule of thumb. That sort of goes without saying.

Manner of consumption:

If you smoke or vape the weed, THC levels drop faster compared to cannabis that's ingested via eating or drinking in teas.


How cannabis interacts with your body

The neurons in your brain communicate with one another and the rest of your body through chemical signals, or "messages." The messages regulate how you feel, what you think, and what you do. Typically, these chemicals (neurotransmitters) come from neurons and travel across a synapse before attaching to specific receptors. This kicks the neuron into action, triggering a chain of events that allow a particular message to be passed along. Like, it's time to eat, or the bathwater is too hot.

The endocannabinoid system (the EC) is a unique communication system in the brain that affects how a person moves and reacts. The chemicals in your brain that respond to the EC are called cannabinoids. Cannabinoids are chemicals also found in cannabis.

The EC communicates its messages differently than typical neurotransmitters because they move "backward." When the neuron is activated, cannabinoids are explicitly produced from fat cells already present in the neuron, attaching to cannabinoid receptors.

THC, or tetrahydrocannabinol, is the psychoactive chemical in cannabis, and it's that which gets you high. Drug tests look for the presence of THC, a cannabinoid found in 99% of cannabis. It's the presence of these cannabinoids in your system that reveals whether or not there's been cannabis consumption.

When consuming cannabis, THC enters your system almost instantly, although it's slower when eaten. However it enters your system, the results are the same, you metabolize psychoactive compounds and feel" "stoned. This quick metabolism is why you feel high for hours rather than days. The amount of THC in cannabis affects this high and determines its strength and the amount of time you feel "stoned."  

Science lesson over!

How long will THC be in your system?

Well, like anything in this field, it's all relative.

Generally, we want to know how long THC metabolites are in fatty tissue.

THC breaks down rapidly and turns into 80 different metabolites; THC itself is only detectable for a short time. However, one of these metabolites is known as THC-COOH. And it’s  this metabolite usually screened for in drug tests. How long this metabolite stays in your bloodstream depends on dozens of different circumstances mentioned above, so working out how long weed stays in your system is a complex proposition.

How is cannabis use detected?

There are various tests used to determine whether or not a person has used cannabis. These include:

Urine Testing

The most common way of testing for the presence of THC is through urine testing. This is because cannabis does not break down as easily through urine. First-time smokers will find that cannabis stays in the system for about a week, and a regular consumer could test positive for THC as long as 12 weeks after last using the substance.

Hair Follicles

Hair follicle testing or a hair test is used to detect regular cannabis. It's believed cannabis has the most significant detection window in hair. Standard hair follicle testing will look for any drug usage over the last three months.

Saliva Test

Testing for cannabis in the saliva or orally is the most basic way to test. THC metabolites can be detected in saliva for an hour after smoking and stay there for 24 hours. For regular smokers, this could be up to 3 days. Heavy consumers are advised to wait at least a week before a saliva test, as it will remain present in oral fluid. 

Blood Test

Blood testing is the most advanced way to screen for cannabis use. Again, its presence depends on various mitigating factors like the THC element and its metabolites. Blood testing for cannabis use isn't that common, but the good news is it doesn’t stay detectable in the blood for long. First-time or infrequent users can expect THC to be noticeable in the blood for a day, heavy users for up to three days.

False Positive Testing

All the above are ways to detect THC. They use whats known as an immunoassay test, or the EMIT, or RIA. If THC, CBD, THC-COOH, or delta-9-tetrahydrocannabinol are detected, the sample is screened again with a GCMS (gas chromatograph-mass spectrometer). This means false positives are infrequent.

In the past, ibuprofen or other by-products would cause false cannabis positives. But today's more modern tests have been adjusted to eliminate that risk.

How long are detection times?

So, depending on the strength of the cannabis you've consumed, frequency of use, and your weight, age, and gender – getting an actual approximation of how long weed stays in your system is difficult to nail down.

However, using best-guess estimates and the law of averages, nail it down to this:


 1st-time use: 5-8 days

 2-4 times a month: 11-18 days

 2-4 times a week: 28-35 days

 5-6 times a week: 33-48 days

 Daily use: 49-63 days


The type of test you take will influence this as well.

Also note that’s a best guess scenario and dependent on many different factors. It can vary significantly in person to person.

As always, the best way to pass any drug test is to abstain altogether. However, it's worth limiting your drug use or beginning a detox should you fear a random drug test.