"i&#039;ve been on phentermine for 3 weeks now. i started off weighing 231 lbs. now, i&#039;m down to 214 lbs. i&#039;ve not experienced the side effects reported. i have an active job which zaps my energy, which may be why my sleeping habits have not changed. however, i can say that i&#039;ve been more productive at work, and on the weekends, i have about a 2 mile jog&#039;s worth of energy to burn."