What are cannabis metabolites?
Cannabis metabolites are the compounds the body makes after it breaks down cannabinoids. THC, CBD, and other cannabinoids enter the blood, pass through the liver, and get converted into new molecules. Those new molecules are metabolites. Some stay active in the body. Others do nothing. Labs test for them in urine, blood, and hair.
THC metabolites
Two THC metabolites matter most.
- 11-hydroxy-THC (11-OH-THC). Made by the enzymes CYP2C9 and CYP3A4. It is psychoactive. After an oral dose, blood levels of 11-OH-THC can run higher than THC itself.
- 11-nor-9-carboxy-THC (THC-COOH). Made from 11-OH-THC. It is not psychoactive. It is the main target of urine drug screens.
Smoking or vaping sends THC into the blood in seconds. The 11-OH-THC peak comes 15 to 30 minutes later. Eating cannabis gives a lower THC peak and more 11-OH-THC, because the liver sees the dose before the blood does.
THC-COOH does not clear fast. It is stored in fat and released over days or weeks. A single use can show up in urine for 1 to 3 days. Daily use can show up for 30 days or more. Body fat, dose, and hydration change the window.
do cannabis metabolites store in fat cells
CBD metabolites
CBD follows a different path. CYP2C19 and CYP3A4 convert it to 7-hydroxy-CBD. That compound goes to 7-carboxy-CBD. Neither is psychoactive. Most CBD leaves the body as 7-carboxy-CBD in urine and bile.
CBD can block CYP2C19 and CYP2D6. This can raise blood levels of other drugs, including some blood thinners and seizure medicines. Talk to a pharmacist before mixing CBD with prescription drugs.
Enzymes and genetics
Cytochrome P450 enzymes run most of this work. CYP2C9 handles a large share of THC. Some people carry CYP2C9 variants that slow the enzyme. Poor metabolizer status is found in about 2 to 3 percent of people of European ancestry. Those people clear THC at a lower rate.
Drug tests
Standard urine immunoassays screen at a cutoff of 50 ng/mL for THC-COOH. A positive screen goes to a second test, most often GC-MS or LC-MS/MS, with a cutoff at 15 ng/mL. Blood tests measure THC, 11-OH-THC, and THC-COOH. Hair tests look for THC-COOH and can reach back months.
Metabolite levels do not measure impairment. THC-COOH has no psychoactive effect. A daily user can test positive while sober.
What is not known
Researchers have not mapped every cannabis metabolite. Minor cannabinoids such as CBG, CBN, and THCV have fewer published pathways. Enzyme activity varies by person, so one detection window does not fit everyone.