i have tried alli (half strength xenical/orlistat) had some side effects when i ate high fat food but if you're on ww then your diet is already low fat ( or atleast thats the theory) and thus xenical wont have much, if any effect, but if you want to try it go for it i say but i would waste money on buying alli again because it wont work as the fat intake per day for me is like 10g lol