Phentermine is the generic form of the brand-name drugs Adipex-P, Suprenza, and Ionamin, which are used for weight loss. Phentermine decreases appetite and stimulates the body to burn calories. Phentermine is a prescription weight-loss drug. Most doctors agree that phentermine works by suppressing the appetite and upregulating the metabolism, though the specific pathways are not fully understood. This is a thyroid forum and that's not really a question for our forum. I can tell you that phentermine is not meant to be a long term medication and there should be breaks in taking it. Hi Caro23. I'm using 15 mg as weight maintenance. I began with 30 mg in Jan 2013 and lost 30 pounds in 2 1/2 months. I stopped the 30MG because I was experiencing some of the things you are experiencing. Original review: Jan. 31, 2019. I started on Phentermine couple months after deciding to make some life changes and to lose weight. I am 5'4 , female, and I got careless and comfortable. I found a Phen Dr. in Anaheim Hills, CA. Done this diet before and worked great. If anyone needs the info it's M.D. Maximum Weight Loss Medical Center the cost is $60 for the first visit, including bloodwork, pills and shot, then $30 a week after that for pills and shot. 714-974-6900. Phentermine supports weight loss by suppressing the appetite and boosting energy. On the most basic level, weight loss is a matter of creating an internal environment in which the body is expending energy in a manner that burns more calories than are being consumed. I was down to salads and water, with no results what so ever. It also makes me very, very sleepy. I need to lose the weight, but nothing working. any comments anyone has would be greatly appreciated! How does Adipex work? Phentermine HCl – the main ingredient in Adipex – is a sympathomimetic amine, which means it stimulates the nervous system. More specifically, it promotes the release of norepinephrine, which is a neurotransmitter (chemical in the brain) that evokes a stress response such as the “fight or flight” reaction and it. For Weight Loss: Prior to using 5'4 165 lbs with hypothyroidism on medication. Working out 3 days a week (500 am). Ate small portions but love carbs.