"started this medicine 6 weeks ago and have lost 10 lbs. i have been watching my diet and walk/jog 2.5 miles 5 days a week with other exercises. i have a hypothyroidism making it very difficult to lose weight. was on this medicine one other time 1.5 years ago for a month straight and realized that my body is immune to it after one week.  now i take it 1 week on, 1 week off.  i notice lots of energy and dry mouth and a happy feeling for the first 4 days and then i start feeling sad, which then goes away in about 4 more days. i have also noticed vision changes in my right eye which i plan to see my eye doctor about.  all in all i recommend phentermine as i would never have lost the weight or had the energy to make the necessary changes."