How long does it take fastin (phentermine) to get out of your urine?

Hard to tell...: It's hard to tell when there won't be any more medication in the body or urine of a particular individual. The half-life of a drug can vary from person to person. Some websites say the half-life of Phentermine (fastin) is somewhere around 16-31 hours. If a half-life is 24hr (1 day), that means after 1 day, half the drug is still in the body (then 1/4, 1/8, 1/16, 1/32, ...1/64 remains after 6 days).

About 14 days: Based on the internet research i did. However, if you are obtaining / using it legitimately, it will not matter, as if positive, you will be asked for the prescriber's name / # to verify and will be non-issue. Good luck.