Why CBD Does Not Cause Failed Drug Tests
Many people that would like to try CBD are hesitant because of the perceived risk of failing a drug test for marijuana. Luckily, this is not the case! Urinalysis screening for marijuana tests for whether or not someone has been exposed to THC, which is a different chemical than CBD and leads to different chemicals in the urine. People can definitely tell a big difference between eating a brownie with 25 milligrams of THC vs 25 milligrams of CBD. Drug screening is just as sensitive to the differences in these two compounds. Read on as we dig into how drug testing works and how that relates to CBD and marijuana. Skip to the end if you want to see the results of my own drug test after regularly taking CBD.
What are drug tests looking for?
For a typical drug test, the person being tested usually has to show up somewhere and pee in a cup (fun right?). The urine sample is eventually tested for evidence that the person did drugs, and also tested in a few more ways to try and determine if it is actually urine. For the drug portion, these tests look for chemicals called drug metabolites. Drug metabolites are what leave the body after the drugs that were taken have been broken down, and are different chemicals than the original drugs. One shudders to think at the activities that might take place if active drugs could be recovered from urine! To summarize: drugs go in, drug metabolites come out. Urine drug screening tests for these metabolites.
How does the test actually show if a drug metabolite is present?
Now to get into the science of how these tests known as immunoassays generally work. The drug test is made of a material that the liquid sample can easily move through from one side to the other. This movement is made possible by something called capillary action, and is the same reason liquid will move up a piece of paper if part of it is dipped in something wet. The liquid sample will contain the drug metabolite for THC if the person who produced the sample had it in their system, and that metabolite will be carried up the strip along with the liquid. As the drug metabolite moves up the strip, it will eventually run into a special protein called an antibody that has been specifically designed to fit that drug metabolite like a lock (the antibody) for a key (the drug metabolite). This antibody will also have something attached to it that will eventually cause it to produce a visible color or other signal. When the drug metabolite hits the antibody, they become attached to each other and continue moving up the strip together until they hit another antibody that is stuck on the positive line of the test strip. When this happens, that area of the test begins to produce the color showing a positive result because the drug metabolite has connected the antibody with the color signal and attached it to the antibody stuck on the positive line. A control line is usually present and works in a similar way, the antibodies on the control line react with molecules that are preloaded into the strip and move up with the liquid. Check out the video below that does a great job visualizing this process used to test for two different components plus a control line.
The difference between THC, CBD, and their corresponding metabolites.
Antibodies are very specific to the drug metabolites they are testing for. Like a lock and a key, the keys may look similar but you need an exact fit to open the lock. If someone is using a CBD product that has been tested to contain 0 THC, and doesn’t get exposed to THC anywhere else, they will not have the THC drug metabolites in their urine.
In the image below, you can see the major structural difference between THC and CBD highlighted by the blue box. THC consists of three rings, all connected. In CBD the middle ring has not been formed. This makes for a bigger difference than it looks like between the two structures, because the bond highlighted in yellow allows the structure to rotate (here’s a video demonstrating bond rotation).
Just like the structures of THC and CBD are different, so are the structures of their corresponding metabolites. A variety of metabolites can be formed by the body adding oxygen atoms at various positions of the molecules. The THC metabolite that is actually tested for in a marijuana drug test is called 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid, with a few different names for short. For the chemists, this metabolite is formed by oxidizing the methyl group at the top of the structure shown to a carboxylic acid. CBD is actually oxidized at the same position to form its major metabolite, but because of the original differences in THC and CBD, these metabolites are also different! Only the THC metabolite will bind to the antibodies on the urinalysis test and cause a positive test result.
What if immunoassay science doesn’t work and the test shows positive?
If the urinalysis immunoassay procedure described above shows positive, that’s not the end! If a test is positive, the urine sample is analyzed using a technique called mass-spectrometry, which is much more sensitive, and gives much more information than an immunoassay. Mass-spectrometry allows the lab to see the exact molecular weight of the compounds present in the urine. THC and CBD metabolites have a different molecular weight, and cannot be confused with this method. Additional, mass spectrometry is combined with an additional technique of either gas or liquid chromatography, which allows for further identification between different molecules.
Need more confidence? I tested myself!
The science of how drug testing works is great, but seeing is believing. I have been drinking Vivify CBD tea daily for the past week, and even drank a cup today while writing this blog post. I briefly stopped writing to go to the store, purchase a marijuana drug test, and test myself! The results are in, and unsurprisingly, I tested negative.
For this test (click the results image to see a bigger version), the two lines being present indicates negative, which is slightly different from how the test described above works. This may work by having a pigment bound to the antibody on the test line that the THC drug metabolite can displace. In any case, Vivify CBD tea is lab tested to contain 12.5 mg CBD per cup, so I have definitely been taking CBD every day, and I have definitely passed the drug test.
CBD is not THC, so be worry free!
If you are anxious about testing positive for marijuana because of CBD use, I hope the above information has helped to alleviate that. There is one important caveat though: if you are using CBD products that contain small amounts of THC, it IS possible to test positive for that THC if you are given a drug test for marijuana. For this reason, it is important to make sure that you only use CBD products that are lab tested to contain zero THC if drug testing is a concern.