"i have been on phend for 5 weeks and my dr put me on b12 shot every week also and i have lost 16 lb so far am so happy with it no side effect at all except dry mouth. i feel thirsty all the time and this is a good thing :&#039;) my energy level is so good i use to wight 162 and now am 146.  i was reading about the med and start to get worried about withdrawal after taking it i still have 15 lbs to lose so if any one can ensure me or tell me what was his/her experience please. thank u"