Many people don’t realize that standard drug tests don’t test for THC; they test for THC-COOH. But what is THC-COOH?
THC-COOH, also called 11-COOH-THC. is formed in the body by oxidation of the active metabolite 11-Hydroxy-THC (also known as 11-OH-THC) by liver enzymes. It is then metabolized further, forming a water-soluble congener which can be more easily excreted by the body.
Unlike THC, 11-COOH-THC is not psychoactive. It does have a much longer half-life, however.
Why Does this Matter?
THC-COOH has a long half-life that can stay in the body for many days. For heavy cannabis consumers, it can stay in the body for weeks or even months (up to 77 days according to one study). This means a drug test can be failed even if the person hasn’t consumed cannabis for weeks.
More selective tests may distinguish between 11-OH-THC and 11-COOH-THC. If 11-OH-THC is detected it’s more of an indicator that cannabis was consumed recently.
Some studies have indicated that THC-COOH plays a role in the pain-relieving and antiinflammatory effects of cannabis. It has also been shown to moderate the effects of THC itself which may help explain the difference in subjective effects seen between occasional and regular users of cannabis.