cannabis in hair how long

If you are asking how long cannabis stays in hair, the short answer is up to 90 days. A scalp hair sample typically shows cannabis metabolites from about 7 days to 90 days after the last use, and that window is measured in months rather than the days you would see with a urine or saliva test. Knowing what drives the number helps you plan ahead.

How long does cannabis stay in hair?

Most labs treat 90 days as the outer limit for scalp hair. Hair grows at roughly half an inch per month, so each half inch of length represents about 30 days of use history. Slower-growing body hair can hold metabolites even longer, which is why scalp hair is the standard sample.

What shortens or lengthens the detection window?

• How often you use: daily use deposits far more metabolite than occasional use.
• Time since last use: the 90-day clock starts at your last session, not your first.
• Hair length and sample site: longer scalp hair and body hair reach further back.
• Hair treatments: bleaching, relaxing and repeated dyeing can lower detectable levels, but results are unpredictable.
• The lab cut-off: a test with a higher cut-off screens out lower concentrations.
• Potency and method: concentrates, edibles and vape oils deliver more THC per session.
• Individual biology: metabolism, body fat and hydration vary from person to person.

Can CBD products cause a positive hair test?

They can. Full-spectrum CBD oils and gummies may carry trace THC, and a repeated daily serving can build up enough metabolite to register on a sensitive hair panel. CBD isolate products with no detectable THC lower the risk, but no product can promise a negative result. Read the third-party lab report before committing to a daily serving.

What should you look for in an at-home hair test?

Kits usually include a cutting guide, foil wrap for the sample, a collection form and a prepaid mailer. Look for a stated cut-off level (often 1 pg/mg for THC-COOH), testing run in an accredited lab, and clear instructions on how much hair is needed, usually a pencil-thickness strand cut close to the scalp.

Orders ship in plain, unbranded packaging within one business day, and tracking reaches your inbox as soon as the parcel leaves the warehouse. Unopened test kits and CBD products can be returned within 30 days for a refund, so you can order with confidence.