[latefordinner]

It's been 5+ years since I used marijuana, and recently(10 days ago) ate a muffin, it was about the size of an egg. It felt like the effects lasted for 12 hours after ingesting. What's the chance this shows up in a hair test in the next few weeks?

[smoothy]

Very good it will.

[DrBill100]

It's been 5+ years since I used marijuana, and recently(10 days ago) ate a muffin, it was about the size of an egg. It felt like the effects lasted for 12 hours after ingesting. What's the chance this shows up in a hair test in the next few weeks?

Very, very unlikely. For reasons which have yet to be explained orally consumed cannabis products do not incorporate into hair. This was first noted in 2007 by Marilyn Huestis with NIH and later confirmed in a test by Auwater, 2010. That is reason #1 that it wouldn't show up.

Number 2, is that THC-COOH is not readily incorporated into hair regardless of route of administration. Usually requires prolonged and repetitive usage. As noted by Musshoff, in a 2006 study “In contrast to other illicit drugs, hair analysis lacks the sensitivity to act as a detector for cannabinoids.” This has been confirmed by researchers both before and after.


Auwärter, (2010) Hair analysis for Delta9-tetrahydrocannabinolic acid A--new insights into the mechanism of drug incorporation of cannabinoids into hair. Forensic Sci Int. 2010 Mar 20;196(1-3):10-3. Orally consumed THCA does not show up in hair.

Huestis (2007) Cannabinoid Concentrations in Hair from Documented Cannabis Users Forensic Sci Int. 2007 July 4; 169(2-3): 129–136.

Musshoff F, Madea B. (2006) Review of biologic matrices (urine, blood, hair) as indicators of recent or ongoing cannabis use. There Drug Monit. Apr 2006;28(2):155-63