Last updated : April 14, 2025
As states continue to legalize marijuana, it proves that Americans consider it to be a manageable recreational drug. Recreational marijuana legalization started in Colorado back in 2012 and spread quickly across the nation. Legalization poses a challenge for employers, though. Advocates for legalization want marijuana removed from company drug testing. Some employers have quietly complied, removing the drug from their company’s drug test and others are adding it after recreational legalization passed in their state.
Since the majority of employers, overall, are keeping marijuana on the company drug test, it’s leading to a renewed interest in testing procedures. People are asking questions such as how long and effectively the drug can be detected in someone’s system.
Several factors play a part
There are several reasons that come into play as to how long marijuana stays in the system.
They include:
- Frequency of use
- Drug potency
- Body mass index (BMI)
- Individual metabolism
- Method of testing
People who rarely smoke marijuana don’t retain it in their system as long as someone who uses every day. Moreover, the body metabolizes everything put in it whether it’s life-sustaining or not. Lastly, when your body metabolizes the THC in marijuana, the metabolites stow away in different areas of the body anywhere from a few days to over a month.
To understand how long marijuana stays in the system, it’s important to know what happens when the drug is used. THC is released when inhaling or consuming pot. It metabolizes rapidly in the body, causing an euphoric effect. While these effects are short-lived, the byproduct, a metabolite named tetrahydrocannabinol carboxylic acid (THC-COOH) stores itself throughout the body awaiting excretion.
Growers continue to try and increase the THC levels contained in marketed marijuana. Plants containing higher levels of THC mean retaining higher levels of THC.
Specifics play a part
An individual’s metabolism is another determining factor. For whatever reason, one person tests positive longer than another. It has to do with the way each body metabolizes the drug. Basically, it boils down to DNA.
Being in shape makes a difference. THC-COOH mainly collects in the fat cells. Thin people don’t have as many fat cells. If you are overweight, the likelihood increases that there is a virtual warehouse full of the stuff!
Detection Methods
Pot has been one of the most commonly tested substances for years. It’s included on most—if not all—standard drug testing panels. There are multiple ways to detect its presence in the system. Standard drug panels, which include 5 panel, 10 panel, 12 panel and DOT drug tests, commonly include marijuana. In other words—unless the marijuana panel is specifically removed, any of these tests could be considered a marijuana drug test.
The only test that can determine the parent drug is the blood test. The other methods detect the metabolites that drugs leave behind. Detection periods vary depending on the type of test used.
If you’re unsure about how long each method detects marijuana, we’re about to break it down for you.
Marijuana in the blood
Marijuana is detected for the shortest time using a blood test. To test positive on a blood test, THC has to enter the bloodstream either through inhalation into the lungs or absorption through the lining of the stomach. If you smoke weed, THC enters your bloodstream within seconds of inhaling it. Edibles take longer as they go through digestion before entering the bloodstream. Therefore, it can take between 30 minutes up to two hours before users begin to experience the effects of the drug.
THC travels through the bloodstream up to the brain which causes the sensation of being “high.” After consumption, the body immediately begins metabolizing the active THC in the blood, breaking it down.
Blood tests aren’t used very often when testing for marijuana though. This is mainly due to the cost-factor. The tests are considered the most intrusive drug testing method, as well. Moreover, the detection period is extremely short-lived. Typically, THC remains in the bloodstream for just three to four hours.
Because blood tests can detect the parent drug, they indicate current impairment. This information can be very useful in determining the accident’s cause. Employers and workers’ comp insurance companies require blood tests in post-accident situations.
Marijuana in saliva
The saliva test detects marijuana use almost immediately, but it only yields a positive result for approximately 24 hours after consuming it. However, the body constantly produces saliva so claims of cheating the test by masking the metabolites in the mouth are false. Also, the test subject never leaves the administrator’s sight so users don’t get an opportunity to tamper with the test.
Delta-9 THC, a psychotropic substance, coats the inside of the mouth and absorbs into the salivary glands after smoking. It happens when you chew edibles as well. The THC remains until new saliva washes it away.
Recent advances in technology coupled with a detection window of up to 72 hours (depending on the drug) make the mouth swab test a solid choice for those who want to determine recent drug use. That’s why employers and law enforcement agencies use this test more than ever. The DOT has approved this test method for use as well but the process is on hold until the Substance Abuse and Mental Health Services Administration (SAMHSA) approves two laboratories to receive specimens.
Marijuana in urine
The most frequently used employee drug test is the urine test. Employers choose them for many reasons. They are cost-efficient, accurate, and, frankly, expected. When employees hear the words “drug test,” they usually assume it’s going to be a urine test.
Since the by-products of using marijuana are fat-soluble, they bond to the fatty tissue in the body which causes them to take longer to expel. Also, cannabinoid metabolites vacate the body at different rates depending on certain body traits, an example of such would be a body mass index.
Detection windows
Someone who rarely uses marijuana in any form is likely to pass a urine drug test after three days. This is because the amount of THC-COOH stored throughout the body has either dissipated or isn’t exiting the body at levels high enough to register. A moderate user, someone who ingests THC up to four times a week, can test positive for up to five days. Daily marijuana users will test positive for up to ten days after discontinuing use.
Lastly, someone who is a chronic marijuana user—as in using multiple times a day, every day—can pop positive on the drug test for up to three months after they stop using! This, of course, stands to reason because the body is constantly retaining THC-COOH which builds up the level stored in the body.
There is a concern about tampering with or substituting urine specimens due to the privacy required during the test. However, thanks to advancing technology in the industry coupled with the very sophisticated laboratory equipment used today, it’s almost impossible for cheaters to succeed.
Marijuana in hair
The hair follicle drug test creates a permanent record of drug use. Drug metabolites store themselves in the hair follicle awaiting excretion. They grow out of the follicle becoming part of the hair itself. Once a part of the hair, the evidence of drug use remains forever. It’s virtually impossible to falsify the results.
The hair follicle test is the least used method though. To date, that’s been due to the cost factor. However, it’s growing in popularity with 7% of employers using it. Many employers are taking a second look because the window of detection looks back ninety days. If you’re wondering how that’s possible, here’s the explanation. Human hair grows at a rate of about 1/2 inch per month. Therefore, a hair sample measuring 1 1/2 inches equals a ninety-day detection period.
Notably, if someone has used drugs for the first time within a week of testing, they may obtain a negative test result. It takes a few days for the metabolites to show up because they need time to grow out of the hair follicle and into the hair shaft.
However, once it’s there, it’s there for good.
Impairment issues
Cannabis has psychoactive and physiological effects when consumed. Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effect is food consumption—commonly referred to as “the munchies.”
Other symptoms include:
- Increased heart rate
- Increased appetite
- Lowered blood pressure
- Impairment of short-term and working memory
- Impaired psychomotor coordination
- Inability to concentrate
Long-term effects are less clear, however, in light of legalization, studies are being formed to determine risk factors.
While many psychoactive drugs clearly fall into the category of stimulant, depressant or hallucinogen, cannabis exhibits a mix of all properties. It may lean the most towards hallucinogenic or psychedelic properties, though, with other effects quite pronounced as well.
Methods of consumption
Users consume marijuana (cannabis) in many different ways, most of which involve inhaling the smoke.
Devices include:
- Small pipes
- Bongs (a portable version of a hookah with a water chamber)
- Paper-wrapped joints
- Tobacco-leaf-wrapped blunts
- Vaping devices
Alternatively, the cannabis plant flowers may be finely sifted producing kief, a powder especially rich in the oil-glands or trichomes which contain the highest amounts of cannabinoids. This powder is used to create edibles.
We mentioned that when someone smokes marijuana, impairment occurs almost immediately. The THC passes from the lungs directly into the bloodstream. Once in the blood, it races to the brain and other organs throughout the body. The “high” peaks in about an hour, and lasts for several hours.
Remember that edibles, on the other hand, often take several hours to reach the height of impairment. The user begins to feel the effects of the drug about 30 minutes after consumption. They are “back to normal” after about five hours.
They say it’s not addicting
Cannabis can be habit-forming and the development of cannabis dependence in some users has been well established. Its effects on intelligence, memory, respiratory functions and the possible relationship of cannabis use to mental disorders such as schizophrenia, psychosis, Depersonalization disorder and depression are still under discussion.
Short-term
The sense of euphoria that accompanies smoking pot is due to the release of dopamine in the brain. During impairment, users experience any or all of the following.
- an altered sense of time
- changes in mood (often described as mellow)
- impaired body movement
- difficulty with problem-solving and focus
- impaired memory
The consumption of high-potency marijuana, using vape oils and dabbing products, is proving that consuming a very high dose of THC can cause hallucinations, delusions, or even psychosis.
Also alarming, some studies show that chronic users exhibit motor skill impairment for days or weeks after discontinuing use.
Long-term
Studies have shown that people who smoked marijuana heavily in their teens and continued heavy use into adulthood lost an average of 8 IQ points before they were forty. However, those who began smoking as an adult did not show a decline in IQ.
Other studies show that people who smoked the drug heavily in their teens suffer from impaired thinking, learning, and memory skills. It’s becoming apparent that the drug affects how the brain builds the connections necessary to complete these tasks.
It’s unclear, however, if this is caused by the THC itself or predisposition factors in the DNA.
But it’s CBD not THC!
It comes as a surprise to some CBD users that taking CBD products puts them at risk of testing positive for marijuana use.
Especially, if someone used the product just before a drug test. They may test positive for the test but take a test later in the day with a negative result. By the way, we conducted an in-house test that produced this result. Moreover, the CBD product our volunteer took advertised that it was THC free!
There are no mandated testing measures in place to regulate the extraction process. Therefore, it is impossible to ensure that THC levels fall under a specific range. If products promoting zero amounts of THC contain enough to produce a positive test result, it stands to reason that any CBD product warrants a risk of a positive test result.
It might be a good idea to educate your employees regarding this information stressing what company policy mandates will happen if they test positive for marijuana. They may rethink the decision to use CBD for medicinal purposes.
Reasons to conduct a marijuana drug test
A documented drug testing policy is designed to protect the company from liability and to educate employees on what’s expected. This drug policy should be fair and reasonable, clearly stated, fully explained, and compliant with all applicable laws at the local, state, and federal level, in the locations where the company has employees.
Failing to do this may result in invalid test results and possibly even an HR-related lawsuit. Fortunately, following a written drug testing policy eliminates these situations. It may include any or all of the following drug testing requirements.
Pre-employment drug test
As one of the most common reasons to perform a drug test, a pre-employment drug test is intended to weed out potential employees who use marijuana or other drugs. This helps employers avoid employees who may become a problem in the first place.
Random drug test
A random drug test ensures that employees did not merely refrain from drug use during the applicant phase. It also helps to maintain higher workplace productivity, morale, and safety because employees know they are subject to a drug test at a moment’s notice. The Department of Transportation requires random drug tests and some employers of the general workforce do so as well.
Post-accident drug test
Immediately after an accident, an employer may conduct (more like “is required to conduct”) a post-accident drug test. In addition to regulatory or workers comp insurance reasons, this also discourages drug use since employees know they can be tested if they are involved in a workplace accident.
Reasonable suspicion drug test
A reasonable suspicion drug test may be conducted if a supervisor suspects drug use based on appearance, behavior, speech, smell, and other indicators. Your drug testing policy must clearly state what indicates reasonable suspicion.
Return to duty
After a positive drug test result, the DOT requires a return to duty drug test before an employee returns to a safety-sensitive role. This is intended to ensure the employee has not consumed any drugs since the last drug test.
DOT drug tests
Employers bound by the Department of Transportation regulations must conduct a DOT drug test in specific situations. As opposed to non-DOT employers, this is not optional and must be conducted according to DOT regulations.
Weeding through it all
Since the pandemic, employers are having trouble hiring and maintaining a workforce. Some business owners are removing marijuana from the drug test as as incentive. An example being a motel owner who can’t find anyone to work third shift. In a tightening labor market, some employers believe the incentive to test less looks enticing because it’s going to cut expenses, and, if it’s legal, why bother? This thinking, however, ignores the safety and productivity impact of marijuana use.
Another headache for employers? For companies operating in multiple states, inconsistency regarding law-making creates problems with standardization of compliance policies company-wide.
Furthermore, marijuana use is still illegal at the national level. However, in November 2019, the House passed the Marijuana Opportunity Reinvestment and Expungement (MORE) Act. If it passes the Senate the federal government will remove marijuana from the controlled substance list.
Our society has deemed pot to be a harmless drug. As a result, its use is becoming more and more widely accepted. Still, employers have every right to remain concerned. Moreover, due to the drive to increase potency, how long before we discover it’s “too much of a good thing” and someone actually overdoses?
The reason we drug test
No matter how they consume it, employees under the influence of marijuana—or any drug—usually become less productive. More importantly, it’s a proven fact that marijuana use affects motor and cognitive skills, possibly for an extended length of time. There is no doubt that marijuana users who are high during working hours increase the risk of workplace accidents. That puts everyone working around them at higher risk too.
In the long run, it’s more cost-effective to maintain a drug-free workplace. In order to avoid the negative effects of marijuana use, it’s critical to have a clearly defined workplace drug testing policy. It should contain procedures for employee and supervisor education, testing protocols, and repercussions for drug use.
Drug testing in the workplace deters some from choosing a lifestyle that includes smoking weed. Routine reminders of your company’s drug policy or on-site refresher courses regarding the dangers of drug use act as further deterrents. Keeping an open dialogue with employees is important too. They need to know that if they suspect a problem, they can bring it to management.
Much like the process of metabolism that goes on within every cell of our bodies, promoting a drug-free workplace is an ongoing process. In the same fashion, just as metabolism is necessary for sustaining life, educating your employees about the dangers of taking drugs could sustain a life too.
Keep up the good work.
