How Long Does Weed Stay in Your System


Cannabis is a drug that became medically available with a prescription in Australia in 2016. It can be smoked, eaten, or vaporised, and it has a variety of effects on the body.

Cannabis is illegal recreationally and needs to be taken under the supervision of a doctor.

Your prescribing doctor will let you know how long you must wait after taking your medicinal cannabis before you can safely drive or operate heavy machinery. The time's patients need to wait before driving vary. This variation is due to a variety of factors, including the type of medication being prescribed as well as the dose of the medication.

One question that many people have about cannabis is how long it stays in the system. In this blog post, we'll discuss how long cannabis can stay in your system, along with the different types of tests used to detect it.

  1. How Long Does Weed Stay In Your System?
  2. What Impacts on How Long Cannabis Is In Your System?
  3. What Are The Laws Surrounding Cannabis In Australia?
  4. What Types Of Tests Are Available For Cannabis Detection?
  5. How Long Do The Effects Of Cannabis Last?
  6. Wrapping It Up
  7. Frequently Asked Questions

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1. How Long Does Weed Stay In Your System?

Wondering how long weed will stay in your system? Generally speaking, THC (the main psychoactive component found in cannabis) can remain detectable for up to 90 days in your system.

Most cannabis drug tests detect metabolites from THC, which stay in your system for much longer than THC.

That said, the exact amount of time it will stay in your system can vary based on a variety of factors. These include how often you use cannabis, how much THC you consume each time, and your metabolism rate.

Due to the lack of reliable data, it is difficult to determine an exact timeline for how long weed will remain in your system. This is why it is essential to keep in mind that the amount of time it takes for THC to be undetectable can vary from person to person.

2. What Impacts on How Long Cannabis Is In Your System?

Many factors can affect how long cannabis will stay in your system. Some of the most important ones include the following:

How Often You Consume Cannabis

Since THC is fat-soluble, it can accumulate in your body over time. Frequent users of THC medications often have detectable cannabis in their system for extended periods when compared to infrequent users.

Chronic users of cannabis have detectable THC metabolites for longer durations than light users, which can result in a positive drug test.

Your Metabolism Rate

The speed of your metabolism plays a significant role in how quickly THC is eliminated from your body.

Those with slower metabolisms will take much longer for the drug to be flushed out, while those with faster metabolisms can expect it to leave their systems quicker.

How Much Cannabis Is Consumed

The amount of the cannabis medication taken and the THC concentration of the medication will also impact how long it stays in your system.

Chronic users who consume larger amounts of THC are more likely to produce a positive result for longer periods of time than those who use smaller amounts.

Body Mass Index (BMI)

Since THC is stored in fatty tissues, which means that people with higher body fat percentages will take longer to flush out the drug. Those who are leaner and have a lower body fat percentage can expect it to leave their bodies quicker.

Lifestyle Factors

Your lifestyle can also affect how long cannabis stays in your system. Those who lead a healthy lifestyle with good nutrition and hydration will find that the drug leaves their bodies quicker than those who don't.

Interestingly enough, exercise was actually found to increase the amount of time THC stays in your system due to an increase in fat cells.

Type Of Drug Test You Take

Lastly, the type of drug test you take will also impact how long marijuana stays in your system.

This is because each test has a different detection window and can detect different levels of THC. Some tests, such as urine tests, are more sensitive and will detect lower amounts of the drug than other tests, like saliva or hair follicle tests.

3. What Are The Laws Surrounding Cannabis In Australia?

In Australia, it is legal to drive with CBD in your system. However, driving with any detectable THC in your system is a crime. This is why all Authorised Prescribers for cannabis (marijuana) medications must get patients to sign that they know it is a crime to drive with any THC in their system.

It's recommended to wait past the point of THC intoxication before driving as tests may still produce a positive result days after taking their medication due to a variety of factors.

Don't risk your safety and the safety of others; make sure you know the laws surrounding cannabis in Australia. Please only take cannabis medications under the supervision of a doctor and wait the time recommended by the doctor before driving.


4. What Types Of Tests Are Available For Cannabis Detection?

Did you know there are different types of drug tests available for marijuana detection?

The most common drug tests used to detect THC in your system include mouth swabs, urine testing, saliva test, and hair follicle tests.

Each test will impact how long cannabis stays in your system and can detect different levels of THC. While this list is not exhaustive, it provides an overview of what you can expect when you take a drug test.

Saliva Based

A salvia-based drug driving test is a quick and easy way to detect low levels of THC in your system. Saliva tests are usually done on the spot and take only minutes to complete and consist of taking a mouth swab and rubbing it against the tongue.

While many believe that ingesting cannabis via capsule pill will not show up in a drug test, this is not true. Any form of cannabis consumption can be detected in saliva tests.

Cannabis can be detected in saliva tests for up to 5-48 hours after consumption and is typically used by police as part of roadside drug testing. Typically, if cannabis was consumed more than 48 hours prior to the test, it will not be detected.

In recent testing, most people have been able to pass a saliva-based drug test three hours after initially consuming cannabis. However, this isn't always the case, and individual results may vary, which is why it's essential to refrain from driving altogether if you have consumed cannabis.


A blood-based drug test is the most accurate way to detect THC metabolites from cannabis in your system. Blood tests measure the active THC levels in the bloodstream, which can be detected for up to 24 hours after consumption. However, regular cannabis users may have it in their blood for up to 6 days!

The way you choose to consume cannabis can also impact how long it's detectable in your system. For example, if you smoke or vaporise cannabis, the active THC will enter your bloodstream much faster than if you consume it orally. However, edible or oil cannabis can still be detected in blood tests up to 24 hours after consumption.

Urine Based

Urine tests are the most common way to detect cannabis in a person's system, especially in a workplace setting. A urine test works by measuring the levels of THC-COOH in your urine sample, which is a metabolite of THC that can be detected for up to 30 days after consumption.

However, this window may be extended if you are a frequent user or have consumed high doses of cannabis. In these cases, the active THC in your urine may be detectable for up to 90 days, resulting in a positive urine test.

The Urine based drug tests are very reliable, as it is difficult to manipulate or tamper with the results or produce a false positive.

Hair Drug Test

A hair drug test can capture weed usage for up to 90 days, making it the longest-lasting test for cannabis detection. Hair tests use a small sample of hair follicles from your head or body to detect THC in your system. This test is usually only used by employers, and it allows them to get an idea of the frequency and amount of cannabis consumed over a 90-day period.

However, there can be contaminants that can cause false positives on a hair drug test, such as secondhand smoke or other hair products.

If you believe you have been wrongly accused of using cannabis or have a false positive hair test, it's a good idea to speak to your employer and ask them for a confirmatory marijuana drug test.

5. How Long Do The Effects Of Cannabis Last?

The effects of cannabis can last anywhere from a few hours to several days, depending on the amount consumed and the method chosen. Some may even feel the impact within a few seconds or minutes of smoking or ingesting it, while others may not feel the effects until several hours later.

Typically, smoking or vaping cannabis will lead to the strongest and quickest onset of effects, while edible cannabis has a much slower onset but longer-lasting effects.

It's important to remember that everyone is different, so the effects you experience with cannabis may be different from those of your friends or family, including how much will make you test positive when it comes to cannabis drug testing.


6. Wrapping It Up

Ultimately, how long cannabis stays in your system will depend on several factors, including the frequency of use, the quantity of THC consumed, the type of test being done and the method of consumption.

It is essential to follow the doctor's instructions during your consultation regarding how long you must wait before you can drive after consuming your cannabis medication. Following the doctor's recommended timeframe will ensure that you are not intoxicated while driving, and it will also minimise the chances of being tested positive for THC at a roadside drug test.

Driving with THC in your system is dangerous to both yourself and everyone else on the road. Above all, it's important to be aware of your individual effects and the risks of cannabis use.

If you believe that medical cannabis could benefit your medical condition, we would recommend filling out our Free Online Pre-Screening. If this questionnaire deems you to be an appropriate patient, you can book a teleconsultation with one of our doctors.

Approved patients are written electronic prescriptions and can purchase their prescribed medications online and have the cannabis medications sent to their homes. Our doctors will create a custom dosage protocol for you which will include how long you must wait before driving. This will minimise many of the potential negative effects that can come with cannabis medications.

Click here to book a video consultation with a doctor and get started on your cannabis journey today.

7. Frequently Asked Questions

How long must I wait after smoking cannabis before driving?

Driving with any detectable THC in your system is a crime. During your consultation with the doctor, you will be given a minimum time to wait after smoking before it is safe for you to drive. This time depends on the frequency that you use the medication and the dose of the medication you take. If you adhere to the prescribed time, you should pass a roadside drug test.

Driving while influenced by THC is extremely dangerous. THC has psychoactive qualities and slows down one's reflexes. It is essential to wait the entire recommended time (from the doctor) before driving, even if you no longer feel intoxicated.

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