How long weed in blood

This means that a person who smokes several times over several days has consumed a higher THC dose than someone who smokes once, and so they are more likely to test positive. The strength of each dose of THC also matters.

Without sensitive laboratory equipment, a person cannot reliably determine the strength of their marijuana. Since fat stores marijuana, people with higher body fat concentrations may metabolize marijuana more slowly than a person with less body fat.

Body mass index BMI is one way to judge body fat. Typically, females have more body fat than males. This means that females may metabolize marijuana slightly more slowly. Dehydration increases concentrations of THC in the body. While drinking lots of water is unlikely to affect a drug test significantly, severe dehydration might. Exercise will not significantly change the rate at which the body metabolizes THC.

Exercising before a drug test, however, might. A small study of 14 regular marijuana users assesses the effects of 35 minutes of exercise on a stationary bike. The results conclude that THC concentrations increased by a statistically significant amount, suggesting that exercise right before a drug test may increase the likelihood of a positive test result.

The researchers believe that exercise may cause fat cells to release THC. For a drug test to be negative, the body must eliminate THC from the system, as well as metabolic chemicals that have links to THC.

People with faster metabolisms typically eliminate THC more quickly than those with slower metabolisms. Ultimately, there are only two strategies that work for this, and they are decreasing the concentration of THC in the marijuana and speeding up the metabolism. Proper hydration can prevent a drug test from showing unusually high THC concentrations. For people whose test results are on the border of positive and negative, this means that being dehydrated may increase the chances of a positive result.

There is no reliable way to speed up the metabolism. Exercise might help the body metabolize more THC, but exercising too near to a test may also cause a positive result. There is no way to accurately predict the amount of time it will take an individual to metabolize marijuana and eliminate it from their bodies. Home tests can help people test themselves for the presence of marijuana in their system.

For almost all people, marijuana should disappear or be very low in concentration within 30 days. For infrequent users, it may take 10 days or less for marijuana to leave the body. Lia Tabackman. This article was medically reviewed by Jason R. Our stories are reviewed by medical professionals to ensure you get the most accurate and useful information about your health and wellness.

For more information, visit our medical review board. Weed can be detected in urine between one to 30 days after your last use. Meanwhile, a saliva or blood test can only detect weed for a few days. The only way to get weed out of your system is to stop using marijuana products. Visit Insider's Health Reference library for more advice.

Lia Tabackman is a freelance journalist covering health and science topics for Insider. She can be found on Twitter LiaTabackman. How one study sparked the debate. Additional comments. Email optional. Receive a selection of our best stories daily based on your reading preferences. Urine test. Blood test. Saliva test. In general, higher doses and more frequent use are associated with longer detection times. For daily users, cannabis may be detectable for several months after last use.

The longest-reported detection times are more than 90 days. Drug tests measure weed and its by-products, or metabolites. According to Mayo Clinic Proceedings , weed is detectable in urine for the following amounts of time after last use:. Cannabis metabolites are fat-soluble, which means they bind to fat molecules in your body. As a result, it can take some time for them to leave your system.

Urine testing is the most common testing method. According to an article in Therapeutic Drug Monitoring , weed is typically detectable in the blood for 1 to 2 days. Chronic heavy use increases the length of time that it can be detected. Weed is detectable in the bloodstream within seconds of inhalation. Some of it is reabsorbed in the blood and broken down. Its metabolites may remain in the bloodstream for days. According to a review on cannabinoids in oral fluid, weed is detectable in saliva for the following amounts of time after last use:.

Weed can enter the saliva through smoking and exposure to smoke. However, its metabolites are only present in saliva when weed has been smoked or ingested. Hair follicle tests assess drug use for up to 90 days. After use, weed reaches the hair follicles via small blood vessels.

Trace amounts may remain in the hair. Since hair grows approximately 0. The active ingredient in weed is a chemical substance called THC, which stands for deltatetrahydrocannabinol.

THC that enters your body is absorbed into the bloodstream. Some THC is temporarily stored in organs and fatty tissues. In the kidneys, THC can be reabsorbed into the bloodstream. THC is broken down in the liver. Drug tests look for these metabolites, which stay in your body longer than THC.