I don’t see why you couldn’t. In fact I was thinking about doing the same thing. I have been doing weight watchers for a couple of months and have lost 23.5 lbs. I read another person’s answer for a similiar question on this and she said that she did WW and Alli and lost 65 lbs in three months. I would say give it a try and if the side affects are too bad just stick with WW. Good luck!