Drug and Alcohol

How Long Does Weed Stay in Your Bloodstream: Understanding THC Processing

How long does weed stay in your bloodstream? Weed can stay in your system a surprisingly long time. Learn the duration and more in our blog.

How Long Does Weed Stay in Your Bloodstream?

Table of Contents

Written by

Brian MooreBrian Moore

Content Writer

Reviewed by

Jeremy ArztJeremy Arzt

Chief Clinical Officer

March 25, 2024

The Edge Treatment Center

One of the most frequently asked questions from both light and heavy cannabis users is, “How long does weed stay in your bloodstream?” — and for good reason, too. In short, it depends on how you consume cannabis, your frequency of use, and your physiology. 

Gain a deeper understanding of THC detection windows, and if cannabis is starting to take hold of your life, learn more about our cannabis addiction treatments at The Edge Treatment Center. We’re here to ladder you out of the hole of addiction.

Key Takeaways

  • Factors influencing weed detection time: Factors such as body fat percentage and hydration levels can influence how long weed is detectable in the bloodstream.

  • Understanding THC blood processing: THC can stay in the bloodstream for up to 12 hours after cannabis consumption.

  • Cannabis detection in urine: Weed can be detected in urine for up to 30 days, depending on usage patterns and metabolism.

  • Traces of cannabis in saliva: Cannabis can be detected in saliva for a shorter period compared to blood or urine, usually up to 72 hours.

  • Detection through hair analysis: Hair analysis can detect cannabis use for an extended period, sometimes months after consumption.

  • Overview of weed detox methods: Weed detoxification can be done through natural methods, commercial products, or at a substance abuse treatment center.

Factors Influencing Weed Detection Time

How long weed stays in your bloodstream depends on a few factors, such as your frequency of use, consumption method, metabolic rate, and body fat percentage. Your detection time frame ultimately depends on these variables.

Frequency Impact

Regular consumption of weed can prolong the detection window in the bloodstream due to accumulation over time.

A person who uses weed frequently is more likely to have higher levels of THC metabolites, leading to an extended period of detection.

Consumption Methods Impact

When smoking or vaping marijuana, THC enters the bloodstream rapidly, leading to quicker detection times. On the other hand, ingesting edibles results in a delayed entry into the bloodstream, affecting how long it remains detectable.

Other methods such as tinctures and topical applications also affect THC absorption rates. Tinctures offer more gradual absorption, while topicals may not enter the bloodstream as significantly, if at all.

Along with the method of consumption, individual factors such as your metabolic rate will influence how long weed stays in your bloodstream.

Metabolic Rate

Certain individual factors influence how long weed stays in the bloodstream, especially your metabolism, which determines how quickly your body can process and eliminate THC. Individuals with faster metabolisms may process THC more quickly, reducing detection times.

Other elements like physical activity, diet, genetic predispositions, and body fat percentage — all of which impact your metabolic rate — also play into how long weed stays detectable in your system.

Body Fat Percentage

Beyond metabolism, your percentage of body fat also plays a role in THC retention. Those with higher body fat percentages may retain THC longer due to its fat-soluble nature.

Genetic factors can also come into play, influencing how quickly you metabolize THC and impacting your detection window.

  • Pros:

    • Quick detection time frames provide accurate results

    • Understanding individual factors helps predict detection windows effectively

  • Cons:

    • Variability in detection times can make it challenging to determine exact durations

Understanding THC Blood Processing

Grasping THC blood processing is key to understanding its bodily impact. It starts when THC enters the bloodstream, leading to a series of metabolic reactions due to blood circulation.

These processes — from inhalation to psychoactive effects — speak to the body’s complex response to THC.

THC Entry Into Bloodstream

After consuming cannabis, THC is rapidly absorbed into the bloodstream through blood vessels in the lungs. Once in the bloodstream, THC can quickly reach various parts of your body, including the brain.

Metabolism Process in Liver

The liver plays a crucial role in metabolizing THC. Upon entering the liver, enzymes break THC down into different compounds known as metabolites. One of the primary metabolites is 11-hydroxy-THC, which has stronger psychoactive effects than THC itself.

Role of Blood Circulation

Blood circulation acts as a transportation system for THC and its metabolites throughout the body. As blood circulates, it carries these compounds to different organs and tissues, distributing them across your bodily systems.

Detection Time Frames

Weed can stay detectable in the bloodstream for up to 12 hours if you’re a regular user, but it’s a sliding scale depending on your body mass, body fat percentage, and frequency of use. The active compound, THC, is what drug tests look for.

However, THC remnants can remain in your system for an even longer period of time. This is because THC is highly fat-soluble and poses a long half-life (the time it takes for THC concentration in the body to decrease by half). According to the National Library of Medicine, the half-life is 1.3 days for irregular users.

Pros and Cons

  • Pros:

    • Efficient distribution of THC to target areas

    • Facilitates metabolism of THC for elimination from the body

  • Cons:

    • Prolonged presence of THC in the bloodstream

    • Increased risk of exposure to THC's psychoactive effects

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Cannabis Detection in Urine

Tracing THC in the body goes beyond the bloodstream, as urine tests can provide a wider window into a person’s cannabis consumption. These tests detect THC metabolites, which linger for up to a month after your body processes the cannabinoids.

THC Metabolites Excretion

When cannabinoids enter the body through weed consumption, they are metabolized into tetrahydrocannabinol (THC). These THC metabolites are then circulated in the bloodstream and eventually excreted through various bodily fluids, including urine.

Urine is a dependable indicator for detecting cannabis use thanks to its ability to retain THC metabolites for an extended period. This translates to a longer detection window when compared to blood tests.

Significance of Urine Tests

Urine tests play a crucial role in identifying drug abuse patterns and monitoring individuals undergoing rehabilitation programs.

By analyzing urine samples for the presence of THC metabolites, healthcare professionals can determine if an individual has used cannabis recently or chronically.


  • Cost-effective method for screening cannabis use

  • Non-invasive procedure with minimal discomfort for individuals


  • Limited ability to provide real-time results

  • Requires specialized laboratory analysis for accurate interpretation

THC Detection Window Comparison: Blood Vs. Urine

The detection window for THC in urine is significantly wider than in blood, remaining for up to 30 days. For reference, tests can detect THC for up to 24 hours in your saliva and 12 hours in your bloodstream.

While blood tests can only detect THC within hours after consumption, urine tests can identify THC metabolites days or even weeks later. This prolonged detection period makes urine testing ideal for assessing long-term drug use.

Traces of Cannabis in Saliva

Saliva testing for cannabis is a snapshot of recent use, capturing THC’s duration in oral fluids. They’re particularly useful for detecting immediate consumption in a quick and easy manner, and are considered to be a more preferable form of testing for recent cannabis use.

THC Presence

THC, the active component in weed, can be detected in saliva after smoking. When smoking cannabis, THC levels quickly enter the bloodstream and are eventually excreted into saliva.

Saliva tests are efficient in detecting recent cannabis use due to the direct transfer of THC from blood to oral fluid. This method offers a quick and non-invasive way to determine recent consumption.

Detection Accuracy

For oral fluid testing, occasional users who have smoked weed will show positive results within one to three days post-use. Regular users may test positive for up to a week.

Compared to blood tests, saliva tests provide a more convenient and accurate means of detecting recent cannabis use since the detection window is shorter.

Shorter Detection Window

Unlike urine or blood testing, which can detect traces of cannabis for a longer period, saliva tests offer a shorter detection window. THC levels in saliva drop significantly within 24 hours after the last use for most individuals, unless you’re a frequent user.

Due to the nature of how substances are metabolized and excreted, saliva testing provides a more precise timeframe for determining recent cannabis use when compared to blood or urine tests.

However, hair tests are likely the most sensitive, able to detect THC for weeks after use.

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Do you have more questions about how long weed stays in your bloodstream? Reach out.

Marijuana Detection Through Hair Analysis

You know how long weed stays in your bloodstream and urine, but what about your hair?

Hair analysis can trace THC back the furthest, up to 90 days, by examining skin oil that transfers to your hair. A person who comes into contact with a THC user could potentially test positive on a hair test, resulting in occasional false positives.

Hair analyses are unique in how they test for THC remnants, as well as the long-term detection window they offer.

Long-Term Detection

Hair analysis test for THC concentration in your hair follicles, or more specifically, the oil which transfers from your skin to your hair.

When an individual consumes cannabis, THC enters the bloodstream and is distributed throughout the body. Over time, the cannabinoids and its metabolites are deposited into hair follicles as they grow.

Hair strands can retain chemical traces of THC for extended periods, making them a valuable source for detecting long-term cannabis use. As new hair grows, it carries a sort of historical record of drug exposure, allowing for analysis even months after consumption.

Challenges and Advantages


  • Variability: Factors such as hair length, color, and treatment methods can affect the accuracy of results.

  • Interference: External contaminants or environmental exposure may influence test outcomes.

  • Cost: Hair analysis can be more expensive than other testing methods.


  • Long-Term Detection: Offers insights into prolonged cannabis use patterns.

  • Non-Invasive: Collection process is simple and does not require specialized training.

  • Reliability: Provides a comprehensive overview of drug exposure over an extended period.

Overview of Weed Detoxification Methods

Natural Methods

A natural detox entails staying hydrated, exercising, and consuming a healthy diet rich in antioxidants. These methods help in flushing out THC from the body naturally over time. Other self-detox methods include:

  • Taking hot baths to soothe physical pains and promote mental relaxation

  • Reduce caffeine intake until anxiety and irregular sleep patterns are solved for

Commercial Detox Products

Commercial detox products such as detox drinks and kits claim to accelerate the detoxification process significantly. However, their efficacy varies — and since these kits are loosely regulated in the U.S., their safety and effectiveness are up for question.

Some users have even reported extreme side effects, such as a 2011 study of a 19 year-old man who developed a case of psychosis after using a commercial detox kit.

Knowing this, reaching out to your doctor or a trusted substance abuse treatment center may be a more effective solution.

Substance Abuse Treatment Center

Trusting a substance abuse treatment center with your recovery is the most firm solution, as you’ll be supported by a team of professionals who can guide you every step of the way.

Following a detox, you’ll go through a set of low-pressure therapies that peel back your addiction and help you heal in a holistic manner — allowing you to turn the page to a happier chapter.

After all, while not as harmful as other classes of drugs, cannabis can quickly go from a recreational activity to an escape mechanism that you depend on when coping with life’s challenges. Leading a good life means facing issues rather than running. Plus, prolonged use can lead to anxiety and even panic attacks

With treatment, you’ll gain the coping skills you need to quit your weed dependence, and nip it in the bud before anxiety or panic strike.

We’re With You, Every Step of the Way

Centers such as The Edge offer a number of therapies designed to help you understand your cannabis addiction, develop coping strategies, and build a solid foundation for long-term sobriety. You’ll step into a structured environment, one where you can hone in on healing and finally kick cannabis for good.

If you’re struggling with cannabis addiction, we’re here to guide you toward a clearer head. Take a virtual tour of our facility for an idea of what awaits.

Final Remarks

So, how long does weed stay in your bloodstream? Weed can generally be detected for up to 12 hours after use. But as you now know, it depends on several factors, most notably frequency of use, metabolism, and the type of test conducted.

Staying informed of these factors is key to managing detection times effectively. Whether through blood, urine, saliva, or hair analysis, this knowledge will drive more informed decisions regarding cannabis consumption and potential drug testing outcomes.

Stay proactive by incorporating suitable detox methods into your routine, adjusting your cannabis use accordingly, and consider seeking professional help if your addiction is taking control of your life.

If you feel like weed's in control, it might be time to take a closer look at your relationship with cannabis. Cannabis use disorder is a real issue, and it can hold you back like any other form of addiction. The Edge Treatment Center provides expert care for weed addiction, dual diagnosis, and more.

Contact The Edge Treatment Center to learn more.

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