Key Takeaways:
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CBD is extracted from the hemp plant, a strain of the Cannabis sativa plant bred to contain low levels of THC.
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THC causes a high, whereas CBD doesn’t: CBD promotes relaxation and a calm state of mind.
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Saliva, urine, blood and hair drug tests are designed to detect THC, not CBD: CBD won’t show up on a drug test.
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Some types of CBD contain low levels of THC, which, with regular use, may accumulate to detectable levels on a drug test
Many people choose to take CBD (cannabidiol) oil or other CBD products, such as gummies and drinks, to help manage pain conditions, anxiety, stress and poor sleep. It doesn't cause a high, can be taken daily and is regulated by the Food Standards Agency (FSA) as a Novel Food.
THC (tetrahydrocannabinol) is another type of cannabinoid, found in cannabis products, that does cause a high. While CBD is legal, THC products, including cannabis, are controlled drugs (Class B) under the Misuse of Drugs Act 1971.
Drug tests are therefore designed to detect THC, not CBD, and CBD won’t cause you to fail a drug test. But as some CBD products contain trace levels of THC, the answer to the question, "Does CBD show up on a drug test?”, isn’t quite as clear-cut as a simple no.
Read on to discover why, in some circumstances, CBD use may cause you to fail a drug test, and what you can do to help prevent this from happening.
Does CBD itself show up on a drug test?
No, CBD won’t show up on a drug test because drug tests aren't designed to detect it.
What do drug tests actually screen for?
Drug tests are conducted for various reasons. They can be carried out on the roadside if you’re suspected of driving under the influence of drugs or routinely if you’re an athlete competing at a club, national or international level, to ensure you’re not using performance-enhancing drugs.
Workplace drug testing may be in place where you work, particularly if your job involves public safety. Drug testing may also be conducted if you’re involved in an accident at work or on the road.
Various tests are used, which might involve testing your saliva, urine, blood, hair or fingernails. They’re used to detect drug use, for example, cannabis. A cannabis drug test looks for the presence of THC (tetrahydrocannabinol). It doesn’t look for CBD (cannabidiol).
CBD vs THC: what is the difference?
CBD and THC are types of cannabinoids found in cannabis. There are over 200 cannabinoids, all present in extracts of the Cannabis sativa plant. CBD and THC are the most well-known and well-understood, but they have very different effects on the brain.
CBD has a relaxing, calming effect, and studies show that it can help to manage chronic pain, anxiety and poor sleep. It’s non-psychoactive and non-intoxicating. CBD won’t cause a high or have any mind-altering effects and is extracted from the hemp plant, a strain of the cannabis plant bred to contain very low levels of THC.
THC, on the other hand, is intoxicating and can cause a high by interacting with receptors in the brain, influencing the release of feel-good hormones and neurotransmitters.
Why CBD use can still lead to a positive result
There are some situations that may cause a positive drug test result for THC, including:
Trace THC in full-spectrum products
In the UK, to be legally sold, all CBD products must be listed on the Food Standards Agency (FSA) Novel Foods register. Under the Misuse of Drugs Act 1971, pure CBD is not a controlled substance, but THC is.
Some CBD products, mainly full-spectrum CBD products, contain trace levels of THC. The Home Office states that this level must be no more than 1mg of controlled cannabinoids per container to meet the exempt product definition in the Misuse of Drugs Regulations 2001.
Full-spectrum CBD products contain all of the cannabinoids found in the hemp and cannabis plants. They’re permitted to contain THC; the amount in the container of product is 1mg or less as long as the total amount of controlled cannabinoids in the container is 1mg or less, and those cannabinoids are not readily recoverable
Conversely, broad-spectrum CBD contains all of the cannabinoids in the hemp and cannabis plant, with the THC removed. CBD isolate products contain pure CBD.
Broad-spectrum and isolate products don’t contain THC and therefore won’t cause a positive drug test. It’s unlikely that occasional use of full-spectrum CBD will lead to THC being detected on a drug test.
THC build-up with heavy or long-term use
However, regular use of full-spectrum CBD or using it at a high dose may cause THC to build up in your system. It may accumulate to detectable levels and lead to a positive drug test.
Mislabelled or unregulated products
There’s a chance that some CBD products contain more THC than they claim, due to mislabelling, either intentionally or unintentionally. This means that you might unwittingly fail a drug test for THC.
To avoid this, only ever buy from reputable brands. See below for more on reducing your risk of a positive drug test.
Cross-contamination and second-hand exposure
It’s unlikely that you’ll fail a drug test for THC by second-hand exposure to THC by spending time with someone using a regulated full-spectrum CBD product. But it’s not impossible to fail a drug test if you’ve spent a lot of time around someone smoking cannabis.
There's also a chance that unregulated CBD products have been cross-contaminated with THC during manufacture.
Types of CBD and their drug-test risk
There’s more chance that certain types of CBD may cause a positive drug test than others:
Full-spectrum CBD
Full-spectrum CBD contains trace amounts of THC: UK law permits up to 1mg of controlled cannabinoids per container of CBD product. This isn’t enough to cause a high, but with regular use, there’s a chance that THC could build up to detectable levels and lead to a positive drug test.
Broad-spectrum CBD
Broad-spectrum CBD has had its THC removed. Therefore, it’s very unlikely that THC will build up in your body to reach detectable levels on a drug test.
CBD isolate
CBD isolate products contain pure CBD with zero THC. Regular use of CBD isolate products, such as Goodrays CBD oil, gummies and drinks, means there’s no risk of THC building up in your system, or of THC showing up on a drug test.
Types of drug tests and their detection windows
When you consume full-spectrum CBD with low levels of THC (or you use cannabis), the THC is broken down by the liver into metabolites. 11-nor-9-carboxy-THC, usually shortened to THC-COOH, is the main THC metabolite.
THC-COOH is inactive and isn’t psychoactive, but it stays in the body longer than the active THC itself. It’s fat-soluble, meaning that it’s stored by the body in the fat cells, and can potentially be detected days or weeks after you’ve had THC in your body.
To reiterate, using CBD with trace or low levels of THC won’t cause a high, but may cause THC metabolites such as THC-COOH to remain in your body.
Different bodily fluids and tissues can be tested and have different detection windows and cut-off levels for THC-COOH. How long THC-COOH may be detectable in your body will depend on your body weight, body chemistry and metabolism, as well as how often you use it, and how much. But as a general rule:
- Urine tests - A urine drug test may detect THC-COOH three to 15 days after use, or longer, up to 30 days, with regular use at a high dose.
- Saliva tests - Saliva drug tests are often used for roadside and workplace drug testing and have a short detection window of around 24 to 48 hours.
- Blood tests - Blood drug tests are sometimes used to confirm saliva and some urine drug test results, usually in a police station or hospital setting. Like urine tests, they have a relatively short detection window of 12 to 36 hours.
- Hair tests - A hair drug test may be used in some legal cases to establish or rule out long-term cannabis use, and can detect THC-COOH for up to 90 days. It cannot identify which product the THC came from, so it will not distinguish CBD use from cannabis use.
Screening vs confirmatory testing
Roadside or workplace drug testing usually involves an immunoassay screening test. Immunoassays are cheap, quick, and provide a negative or presumptive-positive result.
If you receive a presumptive positive, you’ll have another type of confirmatory drug test called gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These confirmatory tests have detection thresholds that provide quantitative, legally defensible values to prove the presence of THC and its amount.
Detection thresholds and cut-off levels
GC-MS and LC-MS drug tests work to a detection level; that is, for a drug test to come back positive, it must have detected a drug, in this case, THC, over a certain level. Below this level, the test will be negative.
Cut-off levels vary by the type of sample being tested. Urine screening for THC-COOH typically uses a cut-off of 50 ng/mL, with confirmatory testing set lower at around 15 ng/mL.
Blood testing works to a completely different scale. The UK drug driving limit for THC is 2 µg/L of blood, which is a near-zero-tolerance threshold and not comparable to urine values. Values range from 20 ng/mL to 50 ng/mL.
How long does CBD stay in your system?
How long CBD (and THC) stays in your system will depend on your individual body chemistry. Having a higher body fat percentage may cause THC to stay in your body for longer, as it’s a fat-soluble molecule that is stored in the fat cells.
THC can stay in your body and potentially remain detectable for up to 30 days. Using high doses of full-spectrum CBD for long periods of time may increase your risk of receiving a positive drug test.
The legal status of CBD in the UK
It’s legal to buy and sell CBD in the UK as long as it contains 1mg or less of controlled cannabinoids per container and it’s registered as a Novel Food with the FSA.
If a CBD product makes a medical claim, such as Epidiolex, a CBD-based drug licensed to treat certain types of epilepsy, it must be registered with the MHRA (Medicines and Healthcare Products Regulatory Agency) for legal sale in the UK. Most CBD products cannot, or do not, make medical claims and, as such, are registered as Novel Foods.
Drug driving and roadside testing in the UK
The drug driving limit for THC is very low, with almost zero tolerance.
Athletes and anti-doping
WADA, the World Anti-Doping Agency for sport, does not list CBD on its prohibited list. Therefore, its use is permitted in sport. But since THC is prohibited, using CBD is at your own risk if you're subject to anti-doping drug tests. To avoid falling foul of a drug test, opt for CBD isolate products that contain zero THC.
How to reduce the risk of a positive drug test
If you’re taking CBD regularly, choose products made using CBD isolate, which doesn't contain any THC, to ensure you have no THC in your body if you’re subject to a drug test.
Always choose CBD products from trusted brands that:
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List their products on the FSA’s Novel Foods register
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Put their products through third-party lab testing for purity
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Display a Certificate of Analysis (CoA) on their website to prove their products contain what they claim they do
What to do if you fail a drug test after using CBD
Standard drug tests for THC are designed to detect THC-COOH, and even though you won’t be high from using CBD, these tests are used as a reliable indicator of recent cannabis use.
Note that we've used the phrase 'cannabis use' here. A retest can confirm how much THC was present, but no test can prove where it came from. If you have only used CBD, request GC-MS/MS confirmatory testing of your B sample, keep hold of the product, its batch number and its Certificate of Analysis, and disclose your CBD use to the tester before the sample is taken rather than after the result comes back.
More information
This article goes into more detail on THC drug testing and how it works, while this article discusses CBD and its likelihood of causing THC to show up on a drug test.
References
CBD drug test: Does CBD show up in a drug test? | Alternaleaf UK. (2024, September 10). https://www.alternaleaf.co.uk/post/does-cbd-show-up-in-a-drug-test
Sharma, P., Murthy, P., & Bharath, M. S. (n.d.). Chemistry, Metabolism, and Toxicology of Cannabis: Clinical implications. https://pmc.ncbi.nlm.nih.gov/articles/PMC3570572/
Ltd, A. D. T. U. (2024, October 14). FAQ-Can CBD show up as THC on a drug test? UK Drug Testing. https://www.ukdrugtesting.co.uk/blogs/news/can-cbd-show-up-as-thc-on-drug-test
This article is for informational purposes only and does not constitute legal or medical advice. Please consult your healthcare provider before starting any new supplement, especially if you are pregnant, breastfeeding or taking other medications.
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