Recreational cannabis is legal in Massachusetts, but your employer does not have to accommodate its use. If your employment subjects you to regular drug testing, you will want to know how long cannabis is detectable in your body. Testing concerns metabolites, substances formed when the body breaks down food or drugs. All sorts of variables impact detection time.
Where Is Cannabis Stored in the Body?
Tetrahydrocannabinol, or THC, is the psychoactive ingredient in cannabis resulting in the high. Some THC, which is fat-soluble, stays in the body’s organs – particularly the liver, lungs and spleen – and fatty tissues temporarily. The liver eventually breaks down this THC into metabolites. One of these metabolites is THC-COOH, formally known as 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol. It is the lipid-soluble THC-COOH that standard drug tests screen for in cannabis testing.
The THC leaves your body through urine and feces. In a matter of hours, it is out of your system. However, the metabolites stay in the body longer. A sensitive drug test can detect THC-COOH in the body a few weeks after you last used cannabis.
How Does THC Affect Your Body?
The chemical structure of THC is similar to anandamide, a fatty-acid neurotransmitter found in the brain. When someone uses cannabis, THC attaches to the body’s endocannabinoid system. The cannabinoid receptors are located throughout the body. THC affects the brain’s reward system, producing the euphoria for which it is famous. The alteration of time so commonly accompanying cannabis use may result from changes in blood flow to the cerebellum.
Keep in mind that because of federal prohibition, research on THC’s effects is limited.
Why Is THC Detectable So Long After Use?
Factors affecting detection time include use frequency and the amount of cannabis consumed. If you only use cannabis once in a while, detectable THC levels are likely gone after ten days or less. If you are a regular user, it may take two weeks or more for THC to leave the system. Those considering themselves heavy cannabis users may have detectable THC levels in their systems for three months or more.
The type of cannabis used affects detection time. Metabolites from edibles stay in the system longer than those from vaped or smoked cannabis.
Another factor determining how long marijuana may stay in the system is dosage. Potent strains of cannabis stick around longer than milder strains. If you consume a lot of cannabis at once, expect a longer detection period than when using smaller amounts.
Individual body chemistry also plays a role. People with more body fat may find THC stays in their system longer because it binds to fat cells.
Conversely, THC exits the bodies of thin people relatively quickly. Overall health makes a difference in how long cannabis stays in your body, as certain medical conditions affect the way the body metabolizes cannabis. There are also medications that may interfere with this process. Lastly, the rate of metabolism relates to genetics, so some people will excrete cannabis more rapidly or slowly based on their genes.
What are the Time Limits for Blood/Urine/Hair Testing?
When someone is arrested on suspicion of drunken driving, the police may test blood to determine the level of intoxication. That does not work with cannabis since it does not stay in the bloodstream for long.
Urine tests are most frequently administered by employers for cannabis testing. For the occasional user, cannabis will show up in urine for one to four days after consumption. Those consuming cannabis a few times a week may have a positive test 10 days or so after their last use. Chronic use may reveal cannabis in their system for up to three months. Fluid intake at the time of the test may also affect results.
Hair tests do not detect initial cannabis use in a prior two-week window. For regular users, the detection period is about three months –but that also depends on the length of your hair. For every month of detection, there is a corresponding 1 cm, or 0.39 inches, in hair length.
Saliva testing is often used to detect cannabis levels. Again, how long afterward a saliva test will turn up positive depends on the individual. If you only indulge once in a while, your saliva may test positive for up to three days after use. Those who consume cannabis on a daily basis may receive a positive test result a month after last partaking.
As the only physician-led and woman-led dispensary in Massachusetts, Garden Remedies is changing the conversation about cannabis. Visit one of our three Massachusetts dispensaries, in Marlborough, Melrose and Newton, or call us at (844) 344-2420. You can also set up a virtual consultation on our website. For all other inquiries, email email@example.com.
Jane Meggitt’s work has appeared in dozens of publications, including USA Today, Zack’s, Financial Advisor, nj.com, The Houston Chronicle and The Nest. She is a graduate of New York University.
- How does marijuana produce its effects? | National Institute on Drug Abuse (NIDA)
- How long does Marijuana stay in your system? (drugs.com)