People often ask how long THC is detectable in the body. The answer is not straightforward.
Some websites state that THC is cleared from the body in a certain number of days. There is more to the story.
The length of time THC is detectable in a person depends on the total amount of THC delivered to the body, how often THC is used, the method of THC use, the person’s metabolism, and the type of test used to measure THC.
The short-term effects of THC are not related to the length of time THC is measured in a test.
A person may not feel the effects of THC, but a test may still detect THC and its byproducts. THC is stored in the body’s fat and can be measured for a long time after the person no longer feels the effects of THC.
So how long does THC stay in the body?
The science provides some information regarding this question.
How Long Does THC Remain in The Body?
The science is clear; no single number provides the answer to this question.
For some people and for some testing methods, THC and its byproducts may be measured for only a few hours. For other methods, THC may be measured for a few days. For other testing methods, THC may be measured for weeks or even longer.
The key to understanding these findings is to consider whether a given testing method measured THC and its byproducts to a level that the testing method could reliably detect.
Just because someone tests positive for drugs, it does not mean that they are under the influence.
The CDC states that the body may show no signs of impairment from cannabis, but the drug may still be present in the body and detectable via a drug test.
For that reason, it is difficult to specify an exact time period for when THC will no longer be present in a person’s body.
What is important to understand is that THC interacts with the body differently compared to other substances.
For example, Ethanol (Alcohol) is water soluble and THC is fat soluble. Because of this characteristic, THC is stored in fat cells and released into the bloodstream over time.
It is for this reason that, after the body and mind understandably feel the intoxicating effects of THC, it may still be detectable in the body for a prolonged period of time.
When THC is metabolized, it produces other compounds. One of these compounds is THC-COOH. THC-COOH is the metabolite that is typically used in cannabis drug tests.
Because the compound that causes the intoxicating effects of THC, THC itself, is not what is being tested for, it is entirely possible for the body to stop feeling the effects of THC and for THC metabolites to still be present in the body.
There are a few reasons why interpreting a drug test as “You are currently under the influence of THC” is not that simple.
Most urine tests that show a presence of cannabinoids show recent exposure and do not necessarily show if a person is under the influence of THC. The CDC states that determining recent cannabis use and if a person is under the influence of THC is not accurate with urine tests.
How long does THC stay in urine?
People tend to discuss urine tests the most when talking about different types of cannabis related drug tests.
With urine tests, the threshold to detect THC can vary and therefore the window in which THC is detectable can vary as well.
The CDC states that a person can test positive for THC metabolites for up to 7 days after use and for frequent users, it can be detected for over 30 days.
Like with the example the CDC provided, a person who uses THC infrequently and a person who uses it frequently, are not going to have the same threshold in which THC is detectable in their urine.
Things that can impact THC detection in urine can include:
- How much THC a person uses
- When a person uses THC
- The potency of THC
- A person’s body mass
- A person’s metabolism
- How concentrated a person’s urine is
Because of all of these factors, it would be misleading to tell someone how many days THC can be detected in their urine.
How long does THC stay in blood?
With blood tests, like with urine tests, there are different factors that can impact how long THC is detectable. THC levels in blood can be low and only detectable for a few hours after use. Like urine tests, with blood tests, other THC metabolites can be detectable for longer.
According to the CDC, THC can be detected in blood for a relatively short time, while metabolites can be detected for a prolonged period.
Because of this, testing blood for THC provides evidence for recent use as compared to urine testing.
However, blood tests do not define when a person was "high".
There are many factors including the rate at which the blood is clearing THC, the amount of THC in the blood, the method of ingestion, and other factors.
How Long Does THC Stay in Saliva?
As with blood tests, saliva tests are used to assess recent cannabis use.
Factors that affect the time a saliva test can detect THC include:
- The saliva test itself
- How the person ingested THC
- How much THC the person ingested
- When the test is performed
Other factors affecting saliva tests that also apply to urine tests are that saliva tests are better at assessing recent cannabis use as compared to urine tests.
Also like urine tests, there is a considerable amount of variability when it comes to determining how long THC stays in a person's saliva.
How Long Does THC Stay in Hair?
Hair tests are different from the other tests because they are more retrospective.
Tetrahydrocannabinol (THC) can be incorporated into hair and provide evidence of use for a prolonged period of time.
Factors that influence how long hair tests can detect THC include:
- Hair length
- Where on the head the sample is taken
- The testing facility and methodology
- Individual factors
Hair tests should not be relied on to provide a precise date or time of THC use.
There are a variety of factors that affect how long THC is detectable.
1. How often THC is used
Someone who uses THC infrequently may be detected for a much shorter period of time than someone who uses THC daily.
Frequent use allows THC to build up in the body, and breakdown products may take longer to be eliminated.
2. How much THC is used
The size of a THC dose affects the total amount of THC metabolites that are present in the body and may be available for detection.
For a given THC dose, it is not possible to determine how long that dose would be detectable.
3. Concentration of THC
THC products come in different concentrations.
More concentrated THC products may allow for a larger THC dose to be administered and, therefore, build up more THC in the body.
This is especially true for THC extracts and oils.
4. How THC is administered
Different methods of administration may result in different rates and extents of metabolism of THC.
THC that is inhaled may be metabolized to a much greater extent than THC that is ingested.
THC that is ingested may be metabolized in the liver.
5. Individual differences
How quickly a person metabolizes THC may be genetically determined.
Metabolism can affect:
- The rate at which THC and its metabolites are eliminated from the body
- The presence and levels of metabolites
- The time for which metabolites can be detected in the body
Because of the above, an exact duration of time for which metabolites will be present in the body cannot be determined.
6. Body Composition
As THC is fat soluble, the fat/muscle ratio may affect the rate at which THC and its metabolites are eliminated from the body.
body composition should not be used to determine the time for which THC and its metabolites will be present in the body.
It is merely one of many factors which should be considered.
7. Test Sensitivity and Cutoff
Drug tests which are manufactured by the same company do not necessarily have the same detection threshold.
The type of lab equipment used to analyze the sample and the type of sample (i.e. blood, urine, etc.) can all affect the outcome of the test.
The laboratory can employ a number of different procedures, e.g. liquid chromatography (LC) or gas chromatography (GC), to analyze the sample.
The laboratory can also perform a number of different confirmatory tests.
A testing cutoff is the minimum level at which a laboratory interprets a test result as a positive test.
An example of a cutoff is, “A methamphetamine test result is considered to be positive if the methamphetamine level in the sample is ≥ 50 μg/L.”
A test which is interpretated as a positive methamphetamine test does not necessarily mean the person is currently impaired.
A positive drug test does not mean a person is currently impaired or under the influence of the substance.
A positive THC drug test may be used to demonstrate that THC metabolites are above the testing threshold.
This means that there is no way to determine the following from a positive THC drug test:
- The time at which THC was ingested
- The amount of THC which was ingested
- Whether THC was ingested recently
- Whether a person is currently impaired
- Impairment may still be present after the effects of THC have worn off.
It is important to understand the limitations of THC testing.
The effects of THC may be long gone, but the body may still show signs of recent use.
This is often the case with urine tests.
A positive urine test indicates recent exposure to cannabis, but says nothing about the user’s current state of mind.
We must separate the idea of recent use from the idea of being high or impaired.
Recent use of cannabis does not mean the user is impaired.
It is important to consider the individual and the test being performed.
Are there ways to determine the approximate time since the user last consumed THC?
Yes.
A user may be completely normal and composed, but that doesn’t mean THC metabolites aren’t still present.
In the case of one time users, THC metabolites can be present in the body for a number of days, and possibly weeks.
This is generally due to variability in the individual and the test being performed.
One time users may test negative in less than a week, while others may not test negative until much longer.
According to the CDC, it is possible for a user to test positive for urinary metabolites for as long as 3 to 4 days after a single exposure.
This is highly variable and depends on a number of factors, including: the potency of the THC, the amount used, the method of consumption, when the test is performed in relation to use, the sensitivity of the test being performed, and the individual being tested.
Because of this, statements such as “THC is cleared in X days after a single use” should be considered with caution.
Repeated or continuous use can greatly increase the length of time that THC and its metabolites can be detected in the user.
Because THC is stored in fatty tissues, frequent exposure to THC can increase the total amount of THC and metabolites in the body. Metabolites can be detected in the body for several weeks, especially in frequent users, according to the CDC.
However, there are variations of frequent users, and some may never test negative for THC. There is no established time when all users will test negative.
Does THC’s effect last longer than THC’s presence in the body?
THC’s effects fade much sooner than THC metabolites, which take longer to be cleared from the body. The effects of THC last only a few hours. The detection time of THC metabolites can range from days to weeks. The detection time is lengthier than the time period of THC’s intoxication effects.
Does drinking a lot of water help?
The answer is no. Even though drinking a lot of water can help mask the presence of THC metabolites, it will not help to really clear THC metabolites from the body.
Although drinking a lot of water can help lower the concentration of THC metabolites in the body, the CDC has noted that the concentration of THC metabolites in the body can influence a drug test, but lowering the body’s concentration of THC metabolites does not mean the body is free of THC.
It is untrue to say that drinking a specific amount of liquid will help to clear THC from the body.
Can exercise help to quicken the elimination of THC?
There are numerous social media posts that provide exercise-related advice to help ‘clean’ THC out of the body.
No reliable forms of exercise exist that will ensure THC is ‘burned’ by a specific date to produce a negative test result.
There are numerous variables that add to the complexity of THC metabolism that make it virtually impossible to “burn off THC.”
Therefore, exercise should not be used to assist in the removal of THC to ensure a negative result on a drug test.
Can ‘Detox’ Products Ensure a Negative Test Result?
There should not be any products available that assure a negative result on a THC test.
Most ‘detox’ products are geared toward improving the urine test results by altering the pH of the urine or adding diuretics.
Drug test results are specific to numerous variables that are often beyond the control of the individual being tested. Therefore, the best assumption is that THC is detectable.
Does Tampering with THC Gummies Alter How Long THC is Detectable?
One post compared the detectability of THC in gummies to that of THC oil and stated that oil is detectable for longer.
Because numerous variables affect the detectability of THC, there are no absolute rules regarding the detectability of THC in different product formats.
Oil and gummies are both delivery methods for THC. If equal quantities of each are consumed, the same variables will affect detectability of each.
Full Spectrum THC Oil drug test concerns:
- There is a good chance a drug test would be positive if the full spectrum THC oil contains THC.
- Products do containing full-spectrum, natural, or plant based ingredients are not always undetectable.
If you are concerned with drug testing, the presence of THC is what you should be concerned about.
Will CBD products cause a positive THC drug test?
Pure CBD products do not contain THC and, therefore, would not cause a positive THC drug test.
However, THC could be present in a CBD product and still give a positive THC drug test.
Depending on the THC and CBD levels of the product, it could cause a positive test.
It is best to check the lab reports of a product to see what the levels of each cannabinoid is if you are concerned about passing a drug test.
What happens if a drug test comes back positive?
How a positive drug test is handled is determined by the reasons the test was done and the rules of the place the test was done (ex. Workplace, school, sports, etc.).
A positive test may still need to be confirmed by a second, more precise test, depending on the rules of the place the test was done.
In general, the policies of the testing place and the laboratory rules should be considered when a test result is given.
When a test may result in an individual losing their job, freedom, or adversely affect their health and well-being, the person should consult with a health care or legal professional.
Can drug tests evaluate a person’s impairment?
Not all drug tests evaluate a person’s impairment.
This is often the case with urine tests.
A urine test helps determine previous exposure to THC.
It does not determine:
- Current level of impairment
- Exact window of time of THC use
- Quantity of THC used
- Level of intoxication
The CDC/NIOSH note on this topic states that it is scientifically inaccurate to conclude impairment from cannabis use based on drug tests.
Why is it so difficult to determine when THC will no longer be detectable?
It is not for a lack of trying.
For the purposes of this discussion, let's define Person A as the cannabis consumer who uses THC in a low, one-time, and/or infrequent manner, and Person B as the cannabis consumer who uses THC in a high, and/or frequent manner.
One would expect Person B to test positive longer than Person A, however that may not always be the case.
It is impossible to know for certain, given the number of variables (including the testing method and laboratory values), that the window of detectability for THC may be extremely wide.
That is the reason a responsible source will avoid providing an exact date when THC will no longer be detectable.
What about drug tests and the world of employment?
The best policy is to assume that the use of any product containing THC may result in a positive urine drug test.
This is the case even if the product is labeled as natural, and/or if the consumer no longer feels impaired.
Drug tests, by their nature, are backward looking. Thus, an employee may test positive for THC even if the employee no longer feels impaired or intoxicated.
If an employee's job requires them to take drug tests, and the employee wishes to use a product containing THC, the employee should review their company policy and determine if there are any exemptions.
What if the user is an athlete?
The laws may vary based on the athlete's sport and/or governing body. Thus, the athlete should review the laws that apply to them.
Some sports commissions create their own lists of prohibited substances and requirements for drug testing.
Athletes need to consult their sport-specific rules for information regarding THC. General information about THC will not be helpful.
If a sport is drug-tested and players wish to compete, they should consult a sport pharmacist or sport physician.
The Most Important Difference: Effects vs. Detection
We have covered the essentials.
Effects of THC
These tell us the lesser and greater impacts that THC has on body and mind.
Some examples include:
- Lapses in judgment
- Loss of memory
- Inability to focus
- Impairment
Detection of THC
This tells us if a test is likely to detect THC or its byproducts.
A person may:
No longer feel any of the effects of THC + still test positive for THC
This is not a medical or pharmacological paradox.
It is simply the difference between the impacts of a substance and the body’s process of eliminating the substance.
Frequently Asked Questions
How long does THC stay in your system?
There is no exact answer to this question. How long THC stays in the body depends on various factors including how often THC is used, how much THC is used, the method of THC use, the test used for drug screening, etc.
How long does THC stay in urine?
How long THC stays in the body depends on various factors, and urine tests are no exception. With that said, urine tests can usually detect THC for a few days to a few weeks or longer in heavy THC users.
How long does THC stay in blood?
Compared to urine tests, blood tests usually can't detect THC for as long of a period of time. However, blood tests can detect THC for a significant period of time if other factors, such as the dose, come into play.
How long does THC stay in saliva?
Like other test types, how long saliva tests can detect THC depends on many factors. With that said, saliva tests are usually designed to detect recent THC use.
How long does THC stay in hair?
Like other tests, the window of detection for hair tests also can't exactly be pinpointed. With that said, hair tests usually can detect THC use for months at a time.
Can THC be detected aft
er the high wears off?
Yes. THC metabolites can be detected by drug tests even after the high wear off.
Does a positive THC tests means a person is currently high?
No. A positive THC test only means THC was used previously and doesn't tell anything about a person's current condition.
Will drinking water help get THC out of your system?
Nothing is guaranteed when it comes to drug tests, but continuously drinking water over an extended period of time can put a person at risk for hyponatremia.
Will working out help get THC out of your system?
Working out will not help someone’s body get rid of THC.
Will a detox product help get THC out of your system?
There is no detox product on the market that will help someone’s body get rid of THC.
Will a product test as negative for THC if it contains full-spectrum THC?
Products that contain THC will test positive for THC.
Will a product test negative for THC if it’s marked as CBD?
There are products on the market that test positive for THC even though they are marked as CBD or Hemp products.
Will a urine test tell when THC was last used?
Urine tests will show THC metabolites, but will not tell when THC was last used.
Will a drug test tell if a person is under the influence of THC?
A drug test will show THC metabolites but will not tell if a person is under the influence of THC.
Final Thoughts
People seem to think there is a set number of days that THC is detectable and that is not the case. There are several factors that determine how long THC is detectable.
The factors that affect how long THC is detectable include:
- The total amount used
- The frequency of use
- The method of use
- The individual’s personal metabolism
- Body fat percentage
- The sample type
- The laboratory’s testing method and cut-off
Blood tests will often detect THC for a much shorter window of time compared to a urine test. Hair tests can detect THC for longer time frames than other test samples.
It is important to understand the following when thinking about drug testing:
A positive THC test does not mean that person is currently under the influence of THC.
Drug tests do not necessarily measure if a person is currently intoxicated.
There are many variables that affect the window of time in which THC is detectable in a person. Because of these variables, you should never assume that you will pass a drug test, even if you think you have allowed sufficient time to detox.
You should always be mindful that there is a risk of a positive drug test, even if you do not think you would still test positive for THC.
Disclaimer
This article is for educational and informational purposes only and should not be considered medical, legal, employment or drug-testing advice. THC detection varies significantly between individuals, products and testing methods. A positive drug-test result does not necessarily indicate current impairment. If you are subject to workplace, sports, legal or other drug-testing requirements, consult the relevant testing authority or a qualified professional for guidance.
