Effectiveness of phenterminePerceived effectiveness: 5 . . . . I just bought it . Phentermine decreases in effectiveness over time. . Phentermine is a diet . I went to get my first B12 injection the other day and I was shocked that the doctor didn't put on gloves to give the injection. . There are many people who are living testimonies to the effectiveness of Phentramin-D and the way it can change a life. I've been taking Phentermine 37. . I like yourself only need to loose about 20-25lbs. . .... more