Wondering how long does THC stay in your system? Use our free THC detox calculator to get a personalised estimate of your detection window across urine, blood, saliva, and hair drug tests — adjusted for your body type, metabolism, and usage frequency.
Fill in your usage pattern and body profile to get a personalised estimate across all four major test types, plus a visual progress bar showing how close you are to clearing each one.
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Based on published studies
Detection window estimates are based on published pharmacokinetic research. Individual results vary. Not medical or legal advice.
Estimate how long THC may remain detectable in your system based on your usage and body profile.
Unlike alcohol or most medications, THC (delta-9-tetrahydrocannabinol) — the primary psychoactive compound in marijuana and weed — is fat-soluble. When you consume cannabis, your body rapidly converts active THC into an inactive metabolite called THC-COOH, which binds to fat cells and is released slowly over days or weeks.
Drug tests don’t detect THC itself — they detect THC-COOH in your urine, blood, or saliva as your body flushes it out. Because fat cells release metabolites gradually, the elimination curve is not linear: the last 10% often takes as long as the first 90%.
This is why daily consumers can test positive for 30–90 days after their last session, while someone who used once may clear a standard urine test in 3–4 days.
Source: Moosmann et al. (2017) — Drug Testing and Analysis; Huestis (2007) — Chemistry & Biodiversity
Each test measures a different biological sample with a different window. Here’s what the research shows for each type, before individual factors are applied.
Standard immunoassay at 50 ng/mL — the most widely used pre-employment and probation test in Canada.
Strict 15 ng/mL GC-MS confirmation extends these windows by ~35%.
Detects active THC in plasma — the most accurate measure of recent impairment. Used in roadside investigations.
Requires a blood draw — rarely used for standard employment screening.
Swab test at 4 ng/mL — increasingly used roadside because it reflects very recent use only.
Body composition has minimal impact — detection is mainly driven by recency of use.
A 1.5-inch sample covers ~90 days. THC metabolites lock permanently into the hair shaft as it grows.
Body composition and metabolism do not affect hair results — the window is fixed by hair growth rate.
Published pharmacokinetic studies identify five primary variables that determine how quickly THC-COOH is eliminated from your body.
The more often you use, the more THC-COOH accumulates in fat tissue. A one-time user may clear in 3–4 days; a daily user may take 30+ days.
THC-COOH is lipophilic — it binds directly to fat cells. Higher body fat creates more storage sites. Lean individuals may clear THC 40–50% faster.
A faster metabolic rate speeds hepatic processing of THC. Younger individuals and those with higher resting metabolic rates clear THC-COOH consistently faster.
Aerobic exercise burns fat tissue, releasing stored THC-COOH for excretion. Avoid heavy exercise 24–48 hours before a test as it can temporarily spike urine metabolite levels.
Normal hydration (2 L/day) supports kidney function and healthy excretion. Extreme over-hydration is detectable by labs and may flag a specimen as inconclusive.
Higher-THC products (concentrates, live resin, distillate) deposit more metabolites per session than lower-potency flower. Roughly double the THC% means double the metabolite load.
The only guaranteed way to eliminate THC metabolites is time. However, several evidence-based lifestyle factors can help your body process and excrete THC-COOH more efficiently.
Moderate cardiovascular exercise
30–45 minutes of aerobic activity 3–4 times per week accelerates fat metabolism. Stop intense exercise 48–72 hours before your test to let metabolite levels stabilise.
Stay well hydrated
Aim for 2–3 litres of water per day. Proper hydration supports kidney function and normal metabolite excretion. Avoid excessive dilution strategies — labs detect them.
Eat a balanced, high-fibre diet
Dietary fibre binds to metabolites in the digestive tract and promotes excretion. Reduce high-fat, high-sugar foods that slow metabolic rate.
Prioritise sleep
Growth hormone released during deep sleep plays a role in fat metabolism. Consistent 7–9 hour nights improve metabolic efficiency across all systems.
A note on “detox kits”: No supplement, drink, or commercial detox product can remove THC metabolites from fat tissue. Products that claim to “flush” your system typically work via temporary dilution — the same effect as drinking extra water. Labs routinely test creatinine and specific gravity to detect diluted specimens.
Standard urine test (50 ng/mL). Average body composition.
The table above shows population averages. The calculator adjusts for your body type, metabolism, and activity level.
Back to calculator ↑For a first-time or infrequent user, a single session typically clears a standard urine test (50 ng/mL) within 3–4 days. Blood and saliva clear in 1–2 days. Regular users accumulate a much larger metabolite load, so the same question has a very different answer depending on your pattern.
Water dilutes the concentration of metabolites in urine, which can lower your result below the cutoff threshold on the day of a test. However, labs check creatinine and specific gravity — if both values are abnormally low, the specimen may be flagged as diluted and you’ll be asked to retest.
Regular cardio exercise speeds fat metabolism, which releases stored THC-COOH for excretion. However, exercising intensely in the 24–48 hours before a urine test can temporarily increase metabolite concentration. Exercise regularly in the weeks before — then rest the days immediately before the test.
A standard 1.5-inch hair sample covers approximately 90 days based on average hair growth of 1 cm per month. THC metabolites are permanently embedded in the hair shaft — they cannot be washed out. Importantly, single or very infrequent use often does not deposit enough metabolites to exceed the detection threshold.
THC-COOH is fat-soluble, meaning it binds to and accumulates in adipose (fat) tissue. People with a higher body fat percentage have more storage capacity for metabolites, prolonging the elimination period. Research consistently identifies body fat as the second most important predictor of detection time, after usage frequency.
Pure CBD does not trigger a positive result for THC. However, many CBD products contain trace THC, and full-spectrum products may contain up to 0.3% THC — enough to accumulate with regular high-dose use. Always check the certificate of analysis if you use CBD and face drug testing.
The 50 ng/mL immunoassay is the standard initial screen for most employment and probation testing. A 15 ng/mL GC-MS test is a more sensitive confirmation method. The lower cutoff extends detection windows by roughly 30–40% for all usage patterns.
The calculator uses base windows drawn from published pharmacokinetic studies with validated multipliers for body composition, metabolism, and activity. It provides a statistically reasonable estimate, not a guarantee — real-world results vary due to genetics, hydration, exact THC potency, and lab-specific procedures.
For a standard urine drug test at the 50 ng/mL cutoff, weed (THC metabolites) can be detected for 3–4 days after a single use, 5–7 days for occasional users, 10–30 days for daily users, and up to 67 days for heavy daily consumers. The marijuana detection time depends heavily on body fat percentage, metabolism, hydration, and how frequently you use cannabis.
Under normal social conditions, second-hand cannabis smoke exposure is extremely unlikely to produce a positive result at the standard 50 ng/mL cutoff. A 2015 Johns Hopkins study found that only extreme, prolonged exposure in an unventilated room produced borderline positive results — and even those cleared within hours. Casual contact with marijuana smoke is not a credible explanation for a failed weed drug test.
When your timeline is clear and you’re ready to enjoy, browse our curated selection of high-quality flower, edibles, concentrates, and more — all shipped discreetly across Canada.
