I havent taken phentermine in 3 weeks will it show in urine drug test?

See below: The half-life of phentermine is anywhere between 19 and 24 hours. In some patients it may go up to 35 hours. I would tell your employer that you have taken phentermine. They should understand!

Not likely: Three weeks is long enough for this drug to clear out of your system. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.