The content provided on this blog is intended for educational purposes only and should not be construed as medical advice. We strongly advise readers to seek guidance from a qualified healthcare professional regarding any medical concerns.

To reflect its medicinal nature rather than recreational use, we prefer the term ‘medical cannabis’ over terms such as ‘marijuana’, “grass”. or ‘dope’ which may carry negative connotations.

The opinions expressed in the blog belong to the respective authors, who are not medical professionals, and may not necessarily align with those of Lyphe Clinic. Lyphe Clinic does not endorse any specific products or services mentioned, except those provided through Lyphe Clinic.

Readers should be aware that the legality of medical cannabis varies by location, and this disclaimer may be subject to periodic updates.

Gloved hand holding a sample of urine.

Key Points

  • THC is metabolised into THC-COOH, which is the compound detected in urine tests. It is stored in fat cells, which are slowly released into the bloodstream over time.
  • Cannabis urine tests commonly employ immunoassay, a highly sensitive method for detecting the THC-COOH metabolite. However, it can only detect recent THC use.
  • The cut-off level for cannabis is typically 50 ng/mL. You can expect to test positive for seven to ten days after smoking or ingesting cannabis.
  • Detection windows vary based on factors such as frequency and amount of cannabis intake, metabolism, body composition, method of consumption, and THC potency.
  • Hydration, exercise, and a healthy diet can support the elimination of THC-COOH, but no specific foods or supplements have been scientifically proven to expedite the process. Detox products should be used with caution, as their efficacy lacks scientific confirmation.


The question of how long you need to be clean to pass a urine drug test for cannabis is complex and varies from person to person. It’s a concern for many who use cannabis, either medically or recreationally, especially in areas where it is still illegal or could affect employment. Hence, this blog aims to dive into scientific research to provide a nuanced look at how cannabis metabolises in the body, the variables that can affect this process, and the typical detection windows.

It is important to remember that this article is not intended to serve as medical or legal advice but aims to provide informative content based on scientific research. Please note that it is crucial to consult with professionals and adhere to legal guidelines specific to your jurisdiction.

Navigating Cannabis Treatment and Drug Tests With Lyphe

When it comes to medicinal cannabis use, look no further than Lyphe, the UK’s preeminent and most expansive medical cannabis clinic. Our top-tier team of doctors and nurse practitioners is devoted to curating the most effective treatment plans for you, guaranteeing unmatched quality of care throughout your healthcare journey. As you navigate drug tests, our team of experts will guide you through the process, offering clear insights into what’s at stake and how to optimally prepare for such evaluations. Contact us today to learn more!

Understanding the Metabolism of Cannabis

Molecular structure of tetrahydrocannabinol.

Before we dive into the timeframe for passing a urine drug test, it is essential to comprehend the mechanisms involved. After cannabis consumption, delta-9-tetrahydrocannabinol (THC), the primary psychoactive compound, gets metabolised by the liver into various metabolites, one of which is THC-COOH.

THC-COOH is what urine drug tests usually screen for, as it remains in the body for an extended period, even after THC itself has been eliminated. However, urine drug tests don’t solely identify THC-COOH. Another metabolite, 11-hydroxy-THC, results from THC breakdown by liver enzymes. This metabolite typically has a shorter detection window, with its highest levels occurring about two hours after consumption and subsequently diminishing.

The Science Behind Urine Drug Tests for Cannabis

For individuals facing the prospect of a urine drug test, particularly in contexts where cannabis use may have consequences, understanding the science behind these screenings is crucial. 

Initial Screening: Immunoassay Tests

The first line of examination typically involves an immunoassay test, often using methods like the enzyme-linked immunosorbent assay (ELISA). This test has a specific “cut-off” level, often 50 nanograms per millilitre (ng/mL)  for THC-COOH, to avoid false positives from trace amounts. If your test shows a level below this cut-off, it’s considered negative.

When you’re using medical cannabis and are undergoing drug testing, understanding the cut-off level is crucial. Depending on the frequency and dosage of your usage, you may or may not exceed this limit. It’s also worth noting that different forms of medical cannabis (e.g., oils, edibles, smoked) might have different rates of metabolism and excretion.

Confirmatory Tests: GC-MS and HPLC

If the initial screening is positive, a confirmatory test using methods like Gas Chromatography-Mass Spectrometry (GC-MS) or High-Performance Liquid Chromatography (HPLC) is usually performed. These highly precise methods can even quantify the amount of THC-COOH in your system.

If you’re using medical cannabis as prescribed by a healthcare professional, it’s vital to discuss the possibility of a positive drug test with them. Some forms and dosages are less likely to produce a positive result. Your doctor might also be able to provide medical documentation that could be useful in the event of a positive test. 

Do Different Methods Affect Results?

Different testing methods can influence the results. For instance, the initial immunoassay tests are more susceptible to false positives due to cross-reactivity with other substances. Hence, if you’re taking other medications or supplements, they might interfere with your test outcomes. Moreover, GC-MS and HPLC are more accurate but can detect usage over a more extended period.

Factors Affecting THC-COOH Detection Time

A 3D depiction of the human anatomy, with a particular focus on highlighting the liver.

Several factors influence the detection time of THC-COOH in urine. Knowing these factors can help you prepare better for a test:

Factor Explanation
Frequency of Use Regular use may extend detection periods
Dosage and Potency Higher or more potent doses may prolong the identification window
Metabolism Individual metabolism rates affect THC clearance
Hydration Levels Adequate hydration supports quick elimination
Body Fat Percentage THC accumulates in fat cells, leading to longer detection
Cannabis Type Different strains/types may impact screening differently
Physical Activity Exercise can temporarily increase THC metabolite release
Diet and Supplements Certain items may influence metabolism and identification 

Cannabis Detection Window in Urine

THC, the primary psychoactive compound in cannabis, has a half-life of approximately one to three days, meaning that it takes this long for half of the THC to be eliminated from the body. However, as also highlighted above, urine drug tests can detect cannabis use much longer than this window due to the presence of THC metabolites, which can remain in the body for several days, weeks, or even months after use.

The approximate detection windows are as follows:

Frequency of Use Detection Time (THC-COOH)
Occasional Use (1-3 Times/Month) Approximately 1-3 days after use
Moderate Use (4-6 Times/Month) About 5-7 days after use
Regular Use (Daily or Near-Daily) Up to 10-15 days or longer after cessation
Heavy/Chronic Use (Multiple Times/Day) Up to 30 days after ceasing cannabis consumption

Furthermore, the type of cannabis product used can also affect identification windows in urine. Edibles, for example, have a longer onset time and can take up to 11 hours to show up after ingestion. In contrast, smoked or vaporised cannabis can be spotted within three hours after use.

Hence, cannabis detection timeframes in urine depend on multiple factors, including the frequency of use, dosage, potency of the cannabis product, individual metabolism rate, and sensitivity of the drug test used. Thus, it’s important to consider these factors when interpreting urine drug test results.

Mitigating Factors and Natural Detox for Urine Drug Test

Woman pouring water from a bottle to a glass.

While the detection windows outlined above provide a general idea, it is important to note that various methods can potentially shorten these periods, allowing users to pass urine drug screenings in a shorter timeframe.

Here are a few examples:

Strategy Description
Hydration Drinking ample fluids may help dilute THC metabolite concentrations in urine
Exercise Regular physical activity can aid in metabolising THC-COOH, as it’s associated with fat cells
Diet Consuming a nutritious, balanced diet can support overall metabolism, potentially expediting the elimination of the substance
Detox Products Some detoxification products or kits claim to hasten THC-COOH removal, although their effectiveness is not universally supported


Determining how long an individual needs to be clean to pass a cannabis urine drug test depends on various factors. While occasional users may test negative within a few days, chronic users may require several weeks or more to achieve the same outcome. Moreover, awareness of one’s frequency and amount of cannabis use, along with metabolism and body composition, is crucial for understanding individual circumstances.

It is essential to remember that this article is based on scientific data available at the time of writing. Always consult with professionals, adhere to local laws, and undertake individual research to make informed decisions regarding drug testing.

Should you have worries about undergoing drug tests whilst using medical cannabis, Lyphe Clinic is well-equipped to give you specialised advice on suitable forms and dosages that are less likely to result in a positive test, whilst also furnishing you with crucial medical documentation. Schedule an appointment with our healthcare experts today! 

Frequently Asked Questions

How long does it take for THC to leave your system for a urine drug test?

The time it takes for THC to leave your system for a urine drug test can vary based on several factors, such as frequency of use and metabolism. However, it is generally identifiable for up to 10-15 days after the last intake in regular users and can remain detectable for 30 days or more in heavy or chronic users.

What factors affect the time needed to detox for a urine drug test?

The time needed to detox for a urine drug test can depend on various factors such as the type of drug used, its potency, quantity and frequency of usage, metabolism, body composition, as well as hydration levels, exercise, and overall health status. No specific foods or supplements have been scientifically proven to expedite the detox process.

Can detox drinks help you pass a cannabis urine test quickly?

The effectiveness of detox drinks to aid in passing a cannabis urine test quickly is not scientifically proven. Exercise prudence when using these products, and it’s advisable to naturally bolster your body’s detoxification mechanisms through adequate hydration, a balanced diet, and regular physical activity.

How do the frequency and potency of cannabis use affect urine test results?

The frequency and potency of cannabis use can affect urine test results in terms of both detection time and toxicity levels. Heavy or chronic users, as well as those who use highly potent cannabis products, are more likely to test positive for a longer period and have higher levels of THC and its metabolites in their urine.

What are the standard cut-off levels for THC in a urine drug test?

The standard cut-off levels for THC in a urine drug test can vary depending on the specific testing guidelines and requirements. However, in general, the cut-off level for THC in a urine drug test is typically set at 50 nanograms per millilitre (ng/mL) or lower.


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Huestis, Marilyn A., et al. “Cannabis Urinary Excretion after Controlled Smoked Administration.” Journal of Analytical Toxicology, vol. 27, no. 6, 2003, pp. 289-297., doi:10.1093/jat/27.6.289.

Karschner, Erin L., et al. “Do Delta-9-Tetrahydrocannabinol Concentrations Indicate Recent Use in Chronic Cannabis Users?” Addiction, vol. 106, no. 10, 2011, pp. 1909-1918., doi:10.1111/j.1360-0443.2011.03591.x.

Lee, Dayong, et al. “Evaluation of the Diagnostic Performance of an Immunoassay for THC and Its Major Metabolite in Serum, Urine, and Oral Fluid Following Single-Dose Administration of THC Edibles.” Journal of Analytical Toxicology, vol. 45, no. 4, 2021, pp. 346-352., doi:10.1093/jat/bkaa186.

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