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How Long Does Medical Cannabis Stay in Your System?

Medical cannabis is now widely available throughout Australia, and every year tens of thousands of people receive prescriptions for cannabis. A common question we receive from our patients during our cannabis consultations is “How long does medical cannabis stay in your system?”.

For medical cannabis patients, it's important to know how the human body processes cannabis. This knowledge helps patients empower themselves in their treatment plan, but also ensure they are staying above board with the strict impaired driving laws across the continent.

How Do Our Bodies Process Medical Cannabis?

Cannabis is processed differently by our bodies depending on how we use it. Medical cannabis can be consumed in two main ways: inhalation or ingestion. Inhaling cannabis means smoking or vaping. Ingesting, on the other hand, means consuming edibles, capsules, or oils and tinctures.

When we inhale cannabis, the active cannabinoids (THC and CBD) are vaporised and inhaled into the lungs. They then pass directly into the bloodstream and that’s why we quickly feel THC's effects after smoking or vaping.

Meanwhile, ingesting cannabis takes a slower route. When we ingest cannabis products, they must first be metabolised in the liver before the cannabinoids pass into our bloodstream. That explains why edibles take more than 60 minutes to have an effect.

From there, a process common to both inhalation and ingestion happens. Cannabinoids from the bloodstream pass into the liver, where they’re processed. First, THC is turned into a more active compound, which is responsible for the psychoactive effects of cannabis.

Then, slowly, it’s converted again into an inactive compound, THC-COOH. This is stored in our fatty tissues and is released gradually into the bloodstream over days or weeks. THC-COOH is eventually excreted from our bodies as a waste product.

How Long Does Medical Cannabis Stay in Your System?

If only there was a simple answer to this question. But, because everybody is different, the answer is a little complicated.

Most tests for medical cannabis are testing for THC (or THC metabolites). So if you only use CBD products, you probably don’t need to worry—tests for medical cannabis don’t look for CBD because there’s no evidence that it causes impairment.

If you are using THC products, research suggests that THC levels in your body peak between three and four hours after consuming cannabis. After 12 hours, THC levels have dropped dramatically. However, studies have found that THC is still detectable in saliva for at least 24 hours and, in some cases, up to eight days.

How long medical cannabis stays in your system depends on many factors. These include how much cannabis you consume, how often you consume, and your body mass index (BMI).

Frequent users may find that THC is detectable in their bodies for longer than with casual users. This is because THC products like THC-COOH build up in stored fats and are released slowly back into the bloodstream.

Finally, the type of test used will affect when medical cannabis is detected.

How Long Does Cannabis Stay in Your Bloodstream?

Blood tests for cannabis aren’t commonly used, but they do exist. In particular, they’re used to confirm intoxication in the case of an accident and sometimes by the defense force and other workplaces.

Blood tests are the most sensitive method of detecting THC, and some studies have shown that THC can be detected for up to 24 hours after consumption. Blood testing is the most accurate way to test for cannabis, and can detect even trace amounts of THC. So it’s best to play it very safe if you expect to take a blood test.

How Long Does Cannabis Stay in Your Urine?

Unlike blood tests for cannabis, urine tests can detect THC-COOH for much longer than 24 hours. Urine tests can detect cannabis from two days (for infrequent users) up to 30 days (for very heavy users) after consuming cannabis.

Unfortunately for medical cannabis users, urine tests aren’t testing for intoxication with cannabis. Instead, they detect the end product of cannabis being processed by your body. So if your workplace mandates urine tests, your medical cannabis product could be detected many days after you last used it.

How Long Does Cannabis Stay in Your Hair?

Finally, hair follicle tests are sometimes used in workplaces to detect long-term cannabis use. Hair follicle tests can identify THC in the body for up to two or three months after use. As a regular medical cannabis user, expect THC to be detectable in your hair follicles while you are using medical cannabis and for up to three months after you stop.

Will You be Subjected to Drug Testing as a Legal Medical Cannabis Patient?

Legislation in Australia has yet to catch up with the widespread use of medical cannabis. Therefore, medical cannabis patients can be subjected to drug testing in various situations. Understanding these situations will help you use medical marijuana safely.

Drug testing only looks for evidence of THC, but detection time depends on the type of test.

Roadside Testing for Medical Cannabis

The most common use of drug testing is mobile (roadside) drug tests. Any police officer in Australia can pull you over and request a roadside drug test. This is usually a saliva test designed to detect THC.

Unlike many other countries, Australia’s police officers don’t need further proof of intoxication to request a drug test. And it’s illegal to have any THC detectable in your body while driving.

A positive result will be followed by another test to confirm, which could lead to medical cannabis patients being charged with impaired driving offences. Because cannabis drug tests don’t directly detect intoxication, this is a consideration for medical cannabis users who use cannabis regularly but don’t drive while under the intoxicating effects.

Workplace Testing for Medical Cannabis

Australians may also be asked to complete a medical cannabis test at work. This is most common in the defense force and industries where safety is critical, like mining, construction, healthcare, and education.

In these circumstances, saliva, urine, and hair follicle tests could be used. A test may detect medical cannabis used several days or weeks earlier. So, play it safe and understand your workplace policy on medical cannabis and prescription medicine when you start using medical cannabis.

Make Informed Choices About Your Medical Cannabis Prescription

So, how long does medical cannabis stay in your system? Testing depends on unreliable measures of intoxication, and THC remains detectable in the body for days, weeks, or even months after use.

Speak to your doctor about medical cannabis testing when you get your prescription. By staying informed of how long medical cannabis remains in your system, you can keep yourself and others safe while benefiting from medical cannabis.

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