"i started taking phentermine, and it did give me headaches and shaking, but i found if i break the pill in half, i don&#039;t have the bad side effects.  i also have lost about 17 lbs. in the last 30 days.  so it is working went from 201 to 184.  i wish everyone the best of luck.  btw i did not change my diet or exercise plan.  my doctor will only put me on this for 21 days. because after that time it stops working.  so i take a half a pill everyday every other month.  i have lost about 50 lbs altogether on this in the last 6 months doing it this way."