How Long Does Cannabis Remain in Your System?

Cannabis, also known commonly as weed, is a drug derived from various strains of the cannabis plant. It can have a number of mental and physiological effects, which can last for a long time after using the drug. Even after the noticeable effects have worn off, the presence of cannabis may still be detectable through a range of different drug tests.

So, how long does cannabis stay in your system, what are the factors that influence this duration, and for how long can it be detected through drug tests?

How Does Cannabis Affect the Body?

Cannabis has two main active ingredients – cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC). Of these, THC is the main psychoactive part of cannabis and the substance responsible for the drug’s ‘high’ and most of the effects generally associated with using cannabis.

The effects of THC on the body and brain can vary depending on a number of factors, including the strength of the drug, the amount used, tolerance and frequency of use.

Some common physical and psychological effects can include:

• Altered senses
• Altered sense of time
• Sense of relaxation
• Pain relief
• Anxiety
• Paranoia
• Nausea
• Impaired reactions and coordination
• Trouble concentrating
• Drowsiness
• Increased heart rate

The way it is taken can also have a bearing. For example, smoking cannabis can cause issues with breathing and the cardiovascular system.

Using cannabis can also have a number of long-term effects. Cannabis use has been linked with increased risk of mental health issues including depression, anxiety and even psychosis. Long-term physical effects can include neurocognitive impairments (brain development issues) and cardiovascular and respiratory problems – although the latter may be linked mainly to smoking the drug.

How Long Does Cannabis Stay in Different Parts of the Body?

When a person smokes cannabis, the THC quickly passes from the lungs into the bloodstream. Other delivery systems, such as edibles, can take longer to work. It may take between half an hour to an hour before any effects are felt but the THC will still eventually enter the bloodstream and from there pass into the brain and other organs throughout the body.

The metabolism of weed in your system depends on how it is taken. When inhaled (typically meaning smoked or vaped), it quickly enters the bloodstream through the lung, with the peak achieved within 6 to 10 minutes after inhalation.

In general, inhalation produces stronger effects than ingesting (eating or drinking) the same amount of THC. After inhalation, THC concentrations are higher in the brain than in the blood. When eating or drinking cannabis, THC will accumulate in fat tissue, from where it is slowly released back into the bloodstream. Most THC will be metabolised by the liver, with around two-thirds (65%) eventually being pooed out and 20% leaving in the urine.

In general, the high from inhaling cannabis may peak around 10 minutes after consumption and typically last 1 to 3 hours – although effects can linger for 8 hours or more. The effects of edibles usually peak around 2 hours after consumption and can last up to 24 hours. Even when you no longer feel the effects, though, traces of cannabis may still be detectable in your blood, pee or hair.

Factors That Influence How Long Cannabis Stays in Your System

The main factor that determines how long cannabis stays in your system is how much you take and how strong it is – with the strength generally referring to THC content.

Other factors can include how you take it (edibles may peak later and last sooner compared to smoking or vaping), your body weight, metabolism and overall health. The frequency of use and tolerance levels can also have an impact, with the plasma half-life of THC being approximately 1 to 3 days in occasional users and 5 to 13 days in chronic users. This means that it can take a lot longer for a regular user to metabolise cannabis compared to an occasional user.

How Is Cannabis Detected in Drug Tests?

There are a number of different types of cannabis drug tests. These include:

• Blood test

This is a very reliable test for recent cannabis use. It can show signs of cannabis with peak accuracy from 24-48 hours, although it can detect heavier or chronic use for up to a month.

• Saliva test

This gives a fast result, which can be obtained just 20-30 minutes after a simple swab test. This can make it useful in situations such as testing for drug use by law enforcement after a road accident. It provides a relatively short detection window of 24 to 48 hours.

• Urine test

This is a common test with a wide range of applications as it can show cannabis use from between 1-30 days, with heavier and chronic use showing up for longer. Single-use of the drug can register for up to 3 days after last use, for example, while chronic heavy use may still show up after four weeks.

• Hair test

THC enters the hair follicles through the bloodstream and can be detected for up to a year after use. It does take around three weeks before it is detectable, though, making this method suitable for long-term but not short-term testing.7

Can You Speed Up the Process of Cannabis Leaving Your System?

Once THC from cannabis is in your system, it needs to be broken down and leave the body naturally. Some things, including exercise, staying hydrated and eating a balanced diet, may help you to process it slightly faster, but there is no reliable way of ‘flushing out’ cannabis metabolism to significantly speed up the process.

Why Knowing Cannabis Detection Times Is Important

Knowing how long cannabis stays in the system is important if you do use the drug, as it may affect things like when you can safely drive, medications you take and other safety-related issues. Cannabis detection times may also be important if you are called to take a drug test for any reason.

If you are concerned about your cannabis use or that of a loved one, get in touch with Addiction Advocates today to find out how we can help.