I took phentermine a few years back - lost 35 pounds easily within 5 or 6 months.
It was the best appetite suppressant I ever used... I didn't even have the desire to eat when I was bored, smelled or saw yummy food, was cooking for others- I often had to MAKE myself eat something.
It changes your metabolism - I DON'T recommend taking it!! You're not supposed to take it forever, but as soon as you stop you gain all the weight back and it's even harder to lose after that.
When I took it, I started at a higher dose, eventually weaned down lower and off it over the period of about a year. (as recommended by my Dr.) In the meantime I improved my eating habits and became more active. I thought that my lifestyle change would help maintain my weight loss after going off it but I was wrong.
It felt so good to lose the weight so fast and I looked really good, but it wasn't 'real' - it was only temporary.
It also made it hard for me to fall asleep & I bruised easily, and I had a very dry mouth (but I didn't care... I was SKINNY!!)
I ended up gaining back more than I'd lost & was depressed and felt like I'd NEVER lose the weight. I ALMOST went back on it out of desperation - but decided I needed to let my body get back to 'normal' so I could REALLY lose the weight and keep it off. It's been over 2 years since I last took it, and I'm just now finally getting this weight loss thing right!
(although I am using Lipo-6 without ephedra from GNC as an appetite suppressant- which seems to be helping me quite well so far)