Hello all- I flucuate in weight about 20 lbs. when I gain weight I start Phentermine and have excellent and quick results within one month I usually lose 8lbs. I have always been a fan of the Phen due the quick amazing results and have been taking them on and off for years now. The reason for this post is that I have currently been taking Phen 37.5 for the passed 3 months and lost only a couple of pounds and very disappointed this time around. Why would that be? I am doing nothing different from my previous times on it also. Why would this work so well on and off for years now not work? I usually never have to take it more than 3 months. Plus we all know Phentermine is not cheap a 30 day supply where I go is $200! Any ideas or suggestions? I also turned 40 this year so maybe my metabolism changed drastically?