About a month ago I started phentermine I did great the first week lost 5 lbs then my appetite started coming back but I still lost 2 lbs. Then it didn't work at all and now I have gained 9 lbs lets do the math I think the phentermine has slowed down my metabolism now and I think my body got messed up. Hopefully it won't last long. I've been dieting and working out and still gaining. But I just wanted to post this because I'm always looking for the easy way out and all it is doing is getting me fatter!!!

Oh the lovely phentermine. That was my diet drug of choice a few years ago. I lost 100 pounds on it. Once i actually started to eat more than 600 cals a day i gained it ALL back...ok, so 600 might be an exaggeration but seriously that stuff is bad news. I think it messes up your body's metabolism by speeding you up so when you are on it that when you come off it, your body doesnt know how to get itself revved up without it. That is what it seemed like to me. Plus it has a tolerance, like you were saying, it works great for a little while then quits. So you have to up the dose until you are on such a high dose that sleeping at night it out of the question, or at least that is how it was for me. It will take a few weeks to get the effects out of your system from what i understand.
Phen was DEFINATLY my easy way out...i can totally relate to what you are going through. I sure loved that stuff when it was working but boy when it doesnt...you are just wiped out. It made me EXTREMILY irritable too. Just give it a couple of weeks and you should be back to normal.

Do you mean you are 9 pounds heavier than when you started, or 2 pounds heavier because you gained back what you lost? You would have had to eat over 30,000 calories more than you burned to gain that much fat back, so it's probably water (because water is mostly what you lose at first on any diet-It's also impossible to lose 5 pounds of fat in a week).
There isn't actually anything in phentermine that speeds up your metabolism. It has a neurological effect that is supposed to make you feel full all the time. The problem is, if for any reason your calorie intake gets below about 1200 calories for more than a few days, you are actually doing more harm than good. You cause your body to go into starvation mode, where you not only NOT loose weight, but your body tries to store anything you do eat.
Phentermine doesn't damage your metabolism. Not eating enough does. The purpose of any diet or pill is to keep us from eating the 2000 or more calories a day that got us overweight-not to keep you from eating anything!
Phentermine does have a "tolerance" level-most doctors won't prescribe it for more than 12 weeks without a break. If you are going to take it, or any other prescription for weight loss, you should devise a plan that incorporates healthy eating. In other words, if you are only eating 600 calories a day, you are going to have to make youself eat!
The other problem is, even if you successfully lose weight with a diet pill, it's still easy to put the weight back on-not because of the pill, but because weight loss' permanence depends on continuing, let's say it again -healthy eating! I know too many people who lost weight, thought they were done, went back to too many calories or junk, and then wondered why they gained it all back.
The "speedy" feeling some people report is a result of the chemical interference in the brain-the "energy" feeling comes along with the "full" feeling, both of which are falsified in the body chemically. You do not actually burn any more calories with it than without it.
I still think they are helpful for cravings for alot of people, but no one NEEDS a diet pill to lose weight. With or without one, you are still going to have to eat healthy and exercise to lose weight.