"i have been on adipex/phentermine 37.5 mg on and off for years. i have found that adipex seems to work very well the first few weeks, but for me it does stop working. i think it&#039;s a good idea to stop taking it for a few days to a week and then start it again. i have adhd and have noticed that adipex also helps me focus more than anything, although it&#039;s not approved for add/adhd. as far as rating adipex for weight loss, i feel it is an excellent medication. i have never had any side effects from adipex!"