How long does pot stay in the hair. How is the amount calculated? I have a hair follical test coming up soon. I haven't smoked pot in a little over 3 months, and have had a hair cut. Any one out there know anything that could be useful? Thanks in advance!

Take a look at this Wikipedia link, it says it can detect up to 6 months, but in general they test only the hair associated with the last 90 days. Alsoif your hair is around 3-5 cm or less (about an inch - inch and a half) it will be gone, in general every 1 cm (about a half inch) of hair measured from the scalp represents the last month and anything you took should show up. But this varies person to person.

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