Short answer
Detection time depends on the test. Urine holds THC metabolites longer than blood or saliva. A single use can clear urine in 1 to 3 days. Long-term heavy use can show up for 30 days or more.
how long does ganja stay in your system
- Urine: 1 to 3 days after one use. 3 to 5 days after moderate use. 10 to 30 days after long-term heavy use.
- Blood: 1 to 2 days after one use. Up to 7 days in people who use each day.
- Saliva: 24 to 72 hours. Most oral fluid samples turn negative inside 48 hours.
- Hair: up to 90 days. Hair tests miss use in the last 1 to 2 weeks because THC needs time to move into the hair shaft.
What changes the window
Four factors move the number up or down: how much, how often, how you took it, and your body.
- Frequency: one session clears faster than 4 sessions a day for years.
- Dose and potency: a 30% THC flower or a 100 mg edible delivers more THC than a 10% flower.
- Route: edibles and concentrates raise the load. THC from an edible passes through the liver and forms more 11-OH-THC and THC-COOH.
- Body fat: THC is fat-soluble. More fat tissue means more stored metabolite and a longer release.
- Metabolism, age, liver function, hydration, and exercise all play a part. Hard exercise can push stored metabolite into blood for a short time.
Test cutoffs
Federal workplace urine tests screen at 50 ng/mL for THC-COOH, also called carboxy-THC. A sample at or above 50 ng/mL gets a second run by GC-MS with a 15 ng/mL cutoff. A screen result below 50 ng/mL is reported as negative. A dilute sample, from drinking large amounts of water, can be flagged and retested. Labs report to the employer, not to the person who gave the sample.
What does not work
No FDA-approved product removes THC from the body or hides it on a test. Niacin, detox teas, vinegar, and herbal pills have no evidence behind them. Niacin can damage the liver at high doses. Water loading lowers metabolite concentration but also drops creatinine, which labs measure to spot dilution.
At the cannabis store
Budtenders sell flower, edibles, vapes, and topicals. They cannot say when your own test will turn negative. Store labels list THC percentage, weight, and batch number. Keep the label if you have a test date, since potency numbers help you estimate dose. THC topicals and CBD products can carry THC. CBD isolate may test at 0% THC, but full-spectrum products often hold small amounts.
If you have a test date
Stop use as early as you can. No timeline fits every person. A heavy user with high body fat can test positive past 30 days. A person who took 1 puff can test negative in 24 hours. Home tests use the same 50 ng/mL cutoff as many labs and give a rough read.