I found Alli to work consistently if you diet and exercise. I think many people think a diet pill is going to work like magic and the pounds will just melt off, however, one must add some cardio and healthy foods for it to work. I felt the Alli helped curb my appetite unlike other diet pills I had tried in the past. I enjoy snacking rather than eating meals and often a snack for me us something sweet. I felt the Alli helped control my need to stick my hand in the candy jar! Effectiveness I wanted to drop 15 pounds before my wedding and decided to give Alli a try. I started using it about 6 months prior, too. The first 12 pounds I lost within 3 and 1/2 months and I lost another 4 before the wedding so it did help me achieve my goal. At this point I had joined WW for maintenance so I stopped using it. Side Effects A few times using the Alli in the beginning, I experienced some headaches, however, I'm not positive if it was the diet causing the headaches. As I mentioned, diet is part of Alli's success. My sugar and caffeine intake was less and headaches could have been from that rather than the pills.