Typically, THC, the psychoactive component of marijuana, is detectable for up to 90 days in hair, anywhere between 1 day to a month or longer in urine, up to 24 hours in saliva, and 12 hours in blood.
However, as with many drugs, how long cannabis remains in your system depends on several factors, including frequency of use, duration of use, and individual metabolism.
Understanding how your body processes THC, how long weed stays in your system, and what to expect when withdrawing can help reduce confusion or distress.
What is THC?
Tetrahydrocannabinol (THC) is the psychoactive chemical in the cannabis plant that causes the feeling of “getting high”. It acts as a partial agonist at the cannabinoid receptors CB1 and CB2 in the central nervous system.
When THC binds to these, it influences regions of the brain that control pain perception, stress response, memory, and muscle coordination. This is why many people feel relaxed, tired, or mentally foggy after using cannabis.[1].
The potency of THC levels in cannabis (the psychoactive chemical) has greatly increased from around 8% in 2008 to over 70% in some dispensary products, increasing concerns about addiction and long-term effects [2].
How Does Your Body Process It?
THC is absorbed into the bodily organs and tissues, such as the heart, brain, and liver, via the bloodstream. Around 65% of cannabis is excreted through feces, 20% through urine, and the rest is stored in the body, such as in immune cells or fat cells [3].
THC stored in the body eventually returns to the bloodstream and is metabolized by the liver. In chronic or long-term users, THC builds up in fatty tissues faster than it can be eliminated, so it may still show up on a drug screening even after weeks of no use (depending on the type of test) [3].
How Long is Marijuana in Your System? THC Detection Windows
THC is highly fat-soluble and has a long half-life (1.3 days for infrequent cannabis users, and between 5 and 13 days for frequent users) [3]. For some, marijuana can leave the system in a few days, for others, it can take several weeks. THC tests also have different detection windows.
| Type of Test | Detection Window |
| Urine | Around 30 days, depending on the frequency of use (this is the most common test type used) |
| Hair | Up to 90 days |
| Saliva | Up to 24 hours |
| Blood | Up to 12 hours |
Why Choose a Detox Program for THC?
Cannabis users often attempt to quit on their own as withdrawal symptoms tend to be less intense or life-threatening compared to alcohol or other drugs. However, many still struggle to quit due to stress, boredom, stomach trouble, or difficulty falling asleep.
It’s also common for individuals who regularly use recreational THC to struggle with underlying mental health challenges such as trauma, loneliness, anxiety, or depression.
A supervised treatment program can address these to support long-term recovery by helping you manage triggers, stress, and unhealthy habits or relationships that contribute to cannabis use.
THC Withdrawal Symptoms and Timeline: What to Expect
THC withdrawal is not as physically intense as other substance use disorders; however, quitting cold turkey is nearly impossible for some, as withdrawal symptoms still occur. The timeline can look different for everyone, but here is a general rundown of what to expect:
Days 1-3 (Onset)
Anxiety, sweating, shaking, intense cravings, inability to sleep, nausea, reduced appetite, mood swings, irritability, and aggression.
Days 3-7
Symptoms become more intense and peak between days 3 and 7. Nausea can become intense, and some struggle with Cannabis Hyperemesis Syndrome, which can lead to intense episodes of cyclic vomiting and increase the risk of dehydration.
Some users may have flu-like symptoms, especially if combining marijuana with other drugs such as opioids or benzodiazepines. Emotional symptoms are also most intense during this stage.
Weeks 2-4
Physical symptoms often subside, and many users report being able to fall asleep more easily. Mood swings, anxiety, irritability, and cravings when exposed to triggers or under stress may continue.
4+ Weeks
Some users experience post-acute withdrawal syndrome (PAWS) in the long-term recovery journey from substance abuse, which includes mood swings, anxiety, and difficulty falling or staying asleep. Treatment focusing on the underlying emotional challenges that lead to cannabis use plays an important role in this stage.
Evidence-Based Cannabis Abuse Treatment in Massachusetts at Trinity Wellness Group
Recovery is not just about stopping substance use—it’s about creating a meaningful, sober life filled with purpose and strength. At Trinity Wellness Group, you’re never alone on your journey. Our multidisciplinary experts work closely with you and your loved ones to ensure continuous care tailored to your unique needs.
Guided by the principles of integrity and authenticity, we are committed to delivering clinically excellent care and the transformative power of lived experience. Contact us today to find support and begin treatment to live a cannabis free lifestyle.
Sources
[1] London, E. et al. (2019). Cannabis effects on brain structure, function, and cognition: considerations for medical uses of cannabis and its derivatives. The American journal of drug and alcohol abuse, 45(6), 563–579.
[2] Stuyt E. (2018). The Problem with the Current High Potency THC Marijuana from the Perspective of an Addiction Psychiatrist. Missouri medicine, 115(6), 482–486.
[3] Bharath, M. et al. (2012). Chemistry, metabolism, and toxicology of cannabis: clinical implications. Iranian journal of psychiatry, 7(4), 149–156.
