Many people faced with an upcoming drug test wonder, “How long does weed stay in your system?” The answer depends on what type of drug test is being conducted, as well as an individual’s body composition, how frequently cannabis was consumed, the dose consumed, and the ingestion method. The most common types of cannabis drug tests are blood tests, urinalyses, saliva tests, and hair tests. Each test has a different length of time that cannabis can be detected.
Different ingestion methods produce different levels of THC in the blood. For example, if you smoke weed, the THC passes from the lungs into your blood stream nearly instantaneously, producing an acute spike of THC in the blood and then a fairly rapid decline. But if you eat an edible, it takes longer for your body to metabolize the THC as it must go through your digestive system, so certain types of drug tests may be able to detect edible usage for a longer time period than if you had smoked. Body composition is also a relevant factor, particularly for urine tests. THC and THC metabolites are fat soluble, meaning they accumulate in adipose (fat) tissue. As a result, cannabis metabolites may be detected for a longer period of time in individuals with higher body fat. Naturally, the amount of THC you consume is also a relevant factor. If you eat 100mg of THC every day, you will be exposed to much higher levels of THC and its metabolites over time. As a result, it will take a longer period of abstinence to produce a negative drug test result than if you take one 5mg puff of a vape pen once.
Blood tests can test for either THC or THC metabolites. Blood tests can show cannabis use for up to 12-24 hours after ingestion in an infrequent user, and up to 7 days in a heavy user. Cannabis blood tests are less common than other methods of drug screening as they are highly invasive. Generally, these tests are conducted in hospital settings after car accidents, injuries, and DUIs.
Saliva testing does not test for cannabis metabolites, but rather tests for the presence of THC. Saliva tests generally have a detection window of about 4-6 hours. These tests are often used when police pull someone over and conduct a roadside test for recent cannabis use, akin to a breathalyzer test for alcohol. Saliva tests are designed to see if someone consumed cannabis very recently.
Hair testing is a common way of testing for cannabis use. Hair tests look for the presence of cannabis metabolites in the hair shaft. In general, hair tests take the bottom 1.5 inches of growth, which generally gives a 90-day detection window. Body hair grows much slower, so cannabis metabolites can be detected for a much longer period of time in body hair. Hair tests are common in employment and judicial settings.
Urine testing is the most common way of testing for cannabis use. These tests are conducted in judicial, scholastic, and employment settings. While the Internet abounds with claims that “THC stays in the urine for a maximum of 30 days,” cannabis metabolites can actually be detected long past this window. Heavy, chronic cannabis use can result in high levels of systemic exposure. A 2009 study found that cannabis metabolites could be detected in a heavy cannabis user’s urine 84 days after cessation. A 2019 study conducted on 70 adolescents and young adults found that after one month of monitored abstinence, 40% still had detectable levels of cannabis metabolites, and 20% would have met the criteria for a “positive” test results according to federal drug testing guidelines.
As we mentioned, THC and THC metabolites accumulate in adipose tissue. The THC and THC metabolites in your fat cells are slowly released into the bloodstream over time. As a result, people often claim that their positive drug test results are due to fasting or exercise. This claim is based on the notion that when you are fasting or exercising, you burn fat and thus could potentially have a spike of THC metabolites in your bloodstream. A study conducted in 2014 found that fasting and exercise produced a slight but statistically significant spike in THC metabolites in the bloodstream, but that the spike disappeared after two hours. However, the increased levels of metabolites were so small that the researchers concluded, “exercise within moderate limits…and short-term fasting…are unlikely to cause interpretational difficulties for urinary drug testing.”
In many cases, it is illegal to attempt to fool a drug test. However, perhaps you live in a state with legal recreational marijuana, and you want to conduct a drug test on yourself. You may be wondering how to get weed out of your system, or how long does weed stay in your urine. However, as explained, the detection time varies depending on numerous factors such as body composition and regularity of use, but there are certain methods that can be used to get weed out of your system fast. Naturally, the method you choose depends on the type of drug test. It is virtually impossible to beat a blood test, as you cannot dilute your blood effectively. A saliva test can be beaten with common home remedies found on the Internet. When asked if a baking soda and salt mouth wash could be used to beat a saliva drug test, Amitava Dasgupta, Ph.D., a professor specializing in Toxicology at the University of Texas-Houston Medical Center answered, “Does it work? Yes, it does.” A hair test is challenging to beat, but it can also be done. A study in the International Journal of Legal Medicine found that a detox shampoo called Ultra Clean removed 36% of THC drug metabolites from the hair. One wash did not remove enough metabolites to beat a drug detection test, but it is thought that multiple washes could remove enough drug metabolites to produce a negative hair test. Urine testing is the most common method of cannabis drug testing and it is also the easiest to influence. The best way to beat a urine test is through dilution. Essentially, one hour before your drug test, you drink around 20 ounces of liquid mixed with creatine, B-vitamins, electrolytes, and zinc. By diluting your urine, there are less drug metabolites present in a urine sample. And by adding in electrolytes, creatine, B-vitamins, and zinc, the concentrations of these compounds appear normal and not intentionally diluted. We hope this article answers your questions about how long marijuana can stay in your system. To learn more about cannabis and how to use Jointly to achieve your wellness goals with cannabis and CBD, head over to our Wellness Center. Download the Jointly app on the App Store or the Google Play Store to get started on your cannabis wellness journey.