How Long Does Cannabis Stay in Your System?
Complete Guide to Cannabis Detection Times
THC can remain detectable in your body from 24 hours to 90 days depending on the test type, usage frequency, and individual factors like body fat and metabolism.
By The Library Team | Last Updated: December 9, 2025
Quick Answer
Cannabis stays in your system for 1-30 days in urine, 2-7 days in blood, 24-72 hours in saliva, and up to 90 days in hair. The exact detection window depends primarily on how often you consume cannabis. Single-use can clear in 3 days, while daily heavy use may take 30+ days. THC metabolites are fat-soluble, meaning they're stored in fat cells and released gradually over time.
THC Detection Times by Test Type
🧪 Urine Test
Most common drug test method
| Usage Pattern | Detection Time |
|---|---|
| Single use (first time) | Up to 3 days |
| Moderate use (4x/week) | 5-7 days |
| Daily use | 10-15 days |
| Heavy chronic use (multiple times daily) | 30+ days |
🩸 Blood Test
Shortest detection window
| Usage Pattern | Detection Time |
|---|---|
| Occasional use | 2-7 days |
| Chronic heavy use | Up to 25 days |
Blood tests detect active THC, not just metabolites. Research in Therapeutic Drug Monitoring shows chronic users may test positive for up to 25 days.
👅 Saliva Test
Used for roadside testing
| Test Type | Detection Time |
|---|---|
| Occasional use | 2-24 hours |
| Lab testing (0.5 ng/mL threshold) | Up to 72 hours |
Saliva tests are increasingly used for workplace and roadside testing. Detection is based on THC presence, not metabolites.
💇 Hair Follicle Test
Longest detection window
| Test Detail | Time Frame |
|---|---|
| Standard test (1.5 inches) | Up to 90 days |
| Time to appear in hair after use | 7-10 days |
Hair tests analyze the most recent 1.5 inches of growth. THC won't appear in hair until 7-10 days after use. Single use may not produce a positive result.
Factors That Affect THC Detection Time
Everyone metabolizes cannabis differently. These factors determine how long THC remains detectable in your specific case.
Usage Frequency
High ImpactDaily users accumulate more THC metabolites than occasional users. Heavy chronic users may test positive for 30+ days.
Body Fat Percentage
High ImpactTHC is fat-soluble and binds to fat cells. Individuals with higher body fat may retain THC longer.
Metabolism Rate
Medium ImpactFaster metabolisms process and eliminate THC more quickly. Age, genetics, and activity level all affect metabolism.
THC Potency
Medium ImpactHigher THC products result in more metabolites to process. Concentrates and high-THC flower extend detection times.
Consumption Method
Medium ImpactEdibles stay in your system longer than smoked cannabis due to liver metabolism creating longer-lasting metabolites.
Hydration Level
Low ImpactStaying well-hydrated supports kidney function and waste elimination, though it won't drastically speed up THC clearance.
How Your Body Processes THC
1Consumption & Absorption
When you smoke or vape, THC enters your bloodstream through the lungs within seconds. With edibles, THC passes through your digestive system and liver first, which takes 30-90 minutes but creates a longer-lasting metabolite called 11-hydroxy-THC.
2Distribution to Fat Cells
THC is lipophilic (fat-soluble), meaning it binds to fat molecules in your body. This is why individuals with higher body fat percentages tend to store THC longer. The THC is then slowly released back into the bloodstream over time.
3Liver Metabolism
The liver converts THC into metabolites, primarily THC-COOH (carboxy-THC). This is the compound most drug tests actually detect—not THC itself. THC-COOH has a much longer half-life than THC, which is why it remains detectable for weeks.
4Elimination
About 65% of cannabis metabolites are eliminated through feces, while 20% leave through urine. The remaining metabolites are stored in fat and released gradually. Complete elimination takes longer for chronic users due to accumulated stores.
Edibles vs. Smoking: Which Stays Longer?
🍪 Edibles
- •Processed by liver into 11-hydroxy-THC (more potent, longer-lasting)
- •Effects last 4-8 hours (vs. 2-4 hours for smoking)
- •Metabolites may remain detectable slightly longer
- •Full absorption takes 1-2 hours
🌿 Smoking/Vaping
- •THC enters bloodstream directly through lungs
- •Peak effects within 10-30 minutes
- •Effects wear off faster (2-4 hours)
- •Slightly shorter detection window than edibles
Bottom Line: While edibles may stay in your system slightly longer due to metabolic differences, the detection time difference is minimal compared to the impact of usage frequency. A daily edible user and daily smoker will have similar detection windows.
Does CBD Show Up on Drug Tests?
Standard drug tests look for THC metabolites, not CBD. However, the type of CBD product you use matters significantly:
CBD Isolate (0% THC)
Pure CBD with all other cannabinoids removed. Will not cause a positive drug testunder normal circumstances.
Broad-Spectrum CBD (0% THC)
Contains other cannabinoids and terpenes but THC is removed. Low risk of triggering a positive test.
Full-Spectrum CBD (up to 0.3% THC)
Contains all cannabinoids including trace THC. May cause positive results with heavy, regular use as THC can accumulate in your system.
If drug testing is a concern, we recommend choosing CBD isolate or broad-spectrum products. Our budtenders can help you find THC-free options—visit us at The Library in West Orange.
New Jersey: Drug Testing, Employment, and Your CREAMMA Rights
Detection windows are physiology. Employment law is policy. New Jersey's Cannabis Regulatory, Enforcement Assistance, and Marketplace Modernization Act (CREAMMA) and the Law Against Discrimination changed what employers can and cannot do with a positive THC test. Here is the framework as it stands.
Can a New Jersey employer fire you for a positive THC test?
Generally, no — not for off-duty cannabis use alone. CREAMMA N.J.S.A. 24:6I-52 prohibits New Jersey employers from taking adverse employment action solely because an employee tested positive for cannabis or used cannabis off-duty during non-work hours. The Law Against Discrimination further protects employees from disparate treatment based on lawful cannabis activity.
Practical exceptions: federal contractors, federally regulated transportation positions (DOT-covered drivers, pilots, maritime), federal grants subject to the Drug-Free Workplace Act, and any role where the employer can document current impairment on the job. A positive urine test does not by itself prove on-the-job impairment — it shows past use within the detection window.
The Workplace Impairment Recognition Expert (WIRE) framework
CREAMMA established a Workplace Impairment Recognition Expert certification. Under the framework as written, an employer must combine a positive cannabis test with a contemporaneous WIRE evaluation documenting on-the-job impairment before taking adverse action. The state's WIRE certification program has been delayed, and employers and employees should consult current NJ Cannabis Regulatory Commission guidance for the enforcement status before any action.
This is a fast-evolving area of law. The information here reflects CREAMMA as enacted, not legal advice. If you face an employment decision tied to cannabis testing, consult a New Jersey employment attorney before acting.
Pre-employment drug testing in New Jersey
Most New Jersey private employers cannot rescind a job offer based solely on a positive cannabis test under CREAMMA's protections. Notable exceptions include federal contractors, federally regulated transportation positions, law enforcement in some contexts, and roles funded by federal grants. The bright-line test: if the employer's drug-testing requirement is mandated by federal law or federal contract, CREAMMA's protections do not override it.
Driving and DUI in New Jersey
CREAMMA legalized possession and use for adults 21+, but driving under the influence of cannabis remains a criminal offense under N.J.S.A. 39:4-50. Unlike alcohol, there is no legal threshold (no "0.08" equivalent) for THC — a New Jersey prosecutor must prove impairment, typically through Drug Recognition Expert evaluation, field sobriety performance, and clinical observation rather than blood THC level alone.
Practical implication: detection windows above do NOT predict DUI exposure. THC metabolites in urine can persist for weeks after impairment has resolved. A positive urine test is not evidence of current intoxication. If you are charged with cannabis DUI in New Jersey, retain counsel — the legal framework is materially different from alcohol DUI.
Federal-overlap roles where CREAMMA does not protect
- DOT-regulated drivers (CDL holders), pilots, and safety- sensitive transportation positions under 49 CFR Part 40
- Federal contractors and recipients of federal grants subject to the Drug-Free Workplace Act of 1988
- Maritime crews under U.S. Coast Guard regulation
- Federal civil service and most federal law enforcement roles
- Roles where the employer can document current impairment on the job through observation plus a contemporaneous WIRE evaluation, per CREAMMA framework
- Positions where federal regulation mandates a drug-free workplace as a condition of operation (some healthcare and nuclear-industry positions)
This is not legal advice.
CREAMMA, the Law Against Discrimination, and federal overlay rules are an evolving framework. Detection-window science is settled; employment-law application is not. If your job or freedom is at stake, consult a licensed New Jersey employment attorney or criminal defense attorney before acting on anything you read on this page.
Frequently Asked Questions
How long does cannabis stay in your urine?
Cannabis can be detected in urine for 3 days after a single use, 5-7 days for moderate users (4 times per week), 10-15 days for daily users, and up to 30+ days for heavy chronic users who consume multiple times daily.
How long does THC stay in your blood?
THC is typically detectable in blood for 2-7 days after use for occasional consumers. However, chronic heavy users may test positive for up to 25 days according to research published in Therapeutic Drug Monitoring.
How long does cannabis stay in your hair?
Hair follicle tests have the longest detection window of up to 90 days. THC metabolites take 7-10 days to appear in hair after use. Standard hair tests analyze the most recent 1.5 inches of hair growth.
How long does weed stay in your saliva?
Cannabis is detectable in saliva for 2-24 hours after use for occasional consumers. Lab-based saliva tests can detect THC at levels as low as 0.5 ng/mL for up to 72 hours after intake.
What factors affect how long THC stays in your system?
Key factors include: frequency of use (daily vs occasional), body fat percentage (THC is fat-soluble), metabolism rate, hydration levels, THC potency of products consumed, and consumption method (edibles stay longer than smoking).
Do edibles stay in your system longer than smoking?
Yes, cannabis that is ingested (edibles) typically stays in your system longer than smoked cannabis. Edibles undergo first-pass metabolism in the liver, creating 11-hydroxy-THC which has a longer half-life than THC from smoking or vaping.
Can you speed up THC detox?
While no method guarantees faster THC elimination, staying hydrated, exercising regularly, eating fiber-rich foods, and abstaining from cannabis use may help your body process THC metabolites more efficiently. Detox products are not scientifically proven to work.
Does CBD show up on drug tests?
Pure CBD isolate should not trigger a drug test. However, full-spectrum CBD products contain trace amounts of THC (up to 0.3%) which may accumulate with regular use and potentially cause a positive result. Choose broad-spectrum or CBD isolate if drug testing is a concern.
Important Note on Drug Testing
Drug tests detect whether cannabis has been used within a given window of time—they do not measure current impairment. Testing positive for THC metabolites does not mean you are currently intoxicated. If you have an upcoming drug test for employment or legal purposes, plan accordingly based on your usage history.
Have Questions About Cannabis Products?
Our knowledgeable budtenders can help you find the right products for your needs, including THC-free CBD options if drug testing is a concern.
Educational Purposes Only: This information is for educational purposes only and should not be considered medical or legal advice. Detection times vary significantly between individuals. Consult with a healthcare provider for personalized guidance. Must be 21+ to purchase cannabis in New Jersey. The Library holds NJ Cannabis Retail License RE000228. Please consume responsibly.