How long does cannabis stay in your system?

“How long does it stay in my system?” usually means one of two things: how long you’ll feel it, or how long a test could detect it. They’re very different timelines.

Feeling it vs testing positive

You typically feel cannabis for a few hours (inhaled) or up to 8+ hours (edibles). But THC and its byproducts linger far longer than the effects, which is why you can test positive long after you feel completely normal.

Rough detection windows

These vary a lot by person and use, but as a general guide:

• Saliva: up to ~24 to 72 hours after use.
• Blood: hours to a couple of days for occasional use; longer for heavy use.
• Urine (the most common test): a few days for one-time use, up to several weeks for daily users.
• Hair: up to ~90 days.

What affects it

• How often you use: frequent use builds up; THC stores in fat and releases slowly.
• Dose and potency.
• Your body: metabolism, body fat, hydration.

There’s no reliable way to “flush” it fast, despite what detox products claim. Time is the only dependable factor.

The driving caveat

Detection isn’t the same as impairment, but Canada’s roadside rules use blood-THC limits. See cannabis and driving. The safe rule stands: never drive after using.

Sources

• Health Canada, Cannabis health effects