How Long Does THC Stay In Your System?

What is THC?

Tetrahydrocannabinol – also known as THC – is probably the most popular cannabinoid. Cannabinoids are naturally occurring chemical compounds found in the cannabis plant, that work by interacting directly or indirectly with the cannabinoid receptors in the human body.

THC is the main psychoactive component of the cannabis plant. It induces feelings of euphoria and elation – a state typically known as ‘the high’. This makes marijuana strains with high THC levels a favourite for recreational users.

Some of the highest THC cannabis strains. Source

How Long Does THC Stay in Your System?

The effects of THC on the body gradually fade away hours after consumption – depending on the quantity consumed and method of consumption. However, it will interest cannabis consumers to know that the drug can still be detected in their systems up to weeks and months after the last consumption.

When THC is absorbed into the bloodstream, it only remains there for a few hours. It is swiftly broken down and modified into molecules known as metabolites. When formed, these metabolites are stored in the body fat and are gradually removed from the via bodily fluids such as urine.

While THC will not be detected in your blood after a few hours, the metabolites formed can be detected in other parts of the body up to 30 days – more, in some cases – after last consumption.

Testing for THC in your system

There are four major ways in which THC can be detected in the system. They are:

  1. Urine testing
  2. Blood testing
  3. Saliva testing
  4. Hair testing

1. Urine testing

Urine testing involves the screening of urine samples for THC metabolites.

According to the Mayo Clinic Proceedings, cannabis is detectable for the following amounts of time after last use, depending on the frequency used.

Cannabis is detectable for the following amounts of time after last use, depending on the frequency used.

  • In occasional users (up to 3 times a week): Up to 3 days after use.
  • In moderate users (4 times a week): 5-7 days after the last use.
  • In chronic users (daily): 10-15 days after last use.
  • In heavy chronic users (multiple times a day): Over 30 days after last use.

Urine testing is the most popular method of detecting cannabis in the system.

2. Blood Testing

THC is absorbed into the bloodstream within seconds of inhalation, where it is then distributed across the body. Typically, THC is detectable in blood for only a short period of time, due to its swift modification to metabolites. It is important to note, however, that cannabis can be detected up to 25 days after last use in heavy chronic consumers.

Laboratory Testing for THC in Bodily Fluids

Laboratory Testing for THC in Bodily Fluids. Source

3. Saliva Testing

Saliva testing involves the screening of saliva samples for THC and its metabolites. While not as popular as urine, saliva testing is able to give accurate results.

According to a 2014 review, THC can be detected in the saliva of an individual for the following amounts of time after last use.

  • Occasional users: 1-3 days
  • Chronic users: 1-29 days

4. Hair Testing

Hair testing for THC involves the screening of hair follicles for trace amounts of THC. THC metabolites enter the hair follicles through blood vessels and can be found in segments of new hair growth.

It has been recorded that THC can be detected in the hair follicles up to 90 days after an individual’s last cannabis use.

Factors that affect how long THC stays in your system

The most determinative factors of how long THC will stay in your system are the amount of cannabis ingested and frequency of ingestion.

Factors such as age, gender, and Body Mass Index (BMI) can be considered when reviewing how the body processes and metabolises cannabis, but these factors pale in importance to amount ingested and frequency of ingestion.

It is important to note that weed strains with high THC levels can result in metabolites that stay in the system longer than strains with low THC levels.


How long does THC stay in your system? The simple answer to this question is it varies according to the individual user’s frequency of use and amount used. While there are average time frames for detecting THC through different methods, individuals time periods will vary. Some methods are also capable of detecting THC much longer after last use than other methods, while some are also more reliable than others.

Published by Neil

Neil believes Cannabis has medical benefits and should be prescribed by a Doctor. This site aims to provide accurate information on the science and legality of Cannabis so you can make informed decisions.

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