How long does marijuana stay in your system should not be confused with how long does a marijuana high last. While you might feel stoned for an hour or so, (read: How Long Does a Marijuana High Last) the metabolized THC stays in your system longer, and is detectable via a number of tests.
The Variables for How Long Does Marijuana Stay in Your System
Here’s a list of variables which affect how long cannabis can be detected after consumption:
- How frequently you consume
- What types of cannabis you consume
- Strains and THC Content
- How you consume it
- Smoke
- Vape
- Edible
- Topical
- Your Body Mass Index (BMI)
- Your gender
Cannabis can be detected in a hair follicle test for as long as 90 days or more.
Types of Tests
This table shows the various types of tests which are used to detect cannabis in your system:
| TEST TYPE | EFFECTIVENESS |
|---|---|
| Blood Test | 25 Days + |
| Urine Test | 30 Days + |
| Saliva Test | @ 29 Days |
| Hair Test | 90 Days |
How Long Does Marijuana Stay in your Blood?
The first thing to know is that cannabis metabolites are fat-soluble. This means they bind to fat molecules which means it can take some time for them to leave your system.
Professional Journals, like Therapeutic Drug Monitoring, suggest cannabis is detectable in the bloodstream basically as soon as it is inhaled. Further, it remains detectable in your blood for up to two or three days; heavy use (daily and chronic) increases the length of time is can be detected in the blood, as much as 25 days or longer.
How Long Does Marijuana Stay in your Urine?
When we continue to look at professional journals, like Mayo Clinic Proceedings, we see that urine holds onto weed metabolites as well.
- 3 days for “occasional” users: up to three times a week
- 5 to 7 days for “moderate” users: four times a week
- 10 to 15 days for “daily” users: daily
- More than 30 days for “chronic” or “heavy” users: multiple times a day
How Long Does Marijuana Stay in your Saliva?
When you smoke or eat cannabis, the metabolites can be present in your oral fluid (saliva) for up to 30 days. In some places where weed is legal, e.g. Michigan, an oral fluid test can be administered for roadside testing.
- For occasional users – up to 3 days
- For chronic/heavy users – up to 30 days
How Long Does Marijuana Stay in your Hair?
Hair tests are the most effective for finding indications of long-term use. The reason is that cannabis metabolites reach hair follicles through small blood vessels and stay there. Human hair grows at about ½ an inch per month, so, the test takes about a 1.5 inch piece of hair from close to the scalp and gets a window into cannabis consumption over the past 90 days.
What’s the Difference between Smoking, Vaping and Eating Cannabis?
Cannabis is metabolized differently depending on if you smoke, vape or eat it. While it’s true you’ll feel the affect of cannabis quicker is you smoke or vape it, it’s also true you’ll feel ‘high’ when you eat it, however, the high you’ll feel is ‘different’ in it’s chemical composition than if you smoke it, due to how it’s absorbed into your bloodstream.
Regardless of whether you smoke, vape or eat cannabis, the metabolites get stored in body fat.
How much do you have to consume to fail a drug test?
While it’s true that THC tests can detect small quantities of cannabis post-consumption, there are several variables which make it difficult to determine what the ‘low-end fail’ threshold is.
These variables include the percentage of THC in any given cannabis strain, how much cannabis was consumed and how (smoke, vape, edibles) and how frequently cannabis is consumed (occasional, moderate, daily or chronic/heavy) and other things.
Examples of Test Results
One consistent finding is that the more frequently you use cannabis, the more likely it is you’ll fail, as compared to infrequent users. In one study done several years ago, two groups of cannabis consumers, “frequent” and “infrequent”, were tested after smoking the same strain and amount of cannabis.
Urine Test Results
They were urine tested hourly for eight hours and the results showed the highest concentrations between 30 minutes and 7 hours after consumption. Their highly sensitive test detected THC 100% of the time in the ‘frequent’ users group and 60-100% of the time in the ‘infrequent’ group.
Hair Test Results
Another study done in 2017 found that 77% of heavy users and 39% of light users tested positive in a study using hair samples. In the study, over 100 consumers were broken into three groups: heavy, light or no use. Their hair was sampled and yielded these results. It also showed zero positive tests from the ‘no use’ control group.
Takeaway: How Long Does Marijuana Stay in Your System
At this point in time, there isn’t a way to determine how long it will take to completely metabolize and eliminate THC from their body. In general terms, for most people, it should disappear or be in very low concentrations within 30 to 60 days.
Factors like body fat, frequency of consumption and THC levels within the cannabis all contribute to the complex calculation of your personal metabolism and it’s ability to flush THC from your system.
So, How Long Does Marijuana Stay in Your System
The bottom line is while there are average times, every person is unique and there’s no specific formula to calculate how long weed will be detectable in your system in particular.
The best measurements are:
- Infrequent Users – about 10 days
- Moderate Users – up to 30 days
- Daily Users – up to 90 days
- Chronic Users – over 90 days
Learn More About Cannabis
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