Several clinical studies have shown that topamax can help people lose weight. The average weight loss with topamax is 3% of your starting body weight after 3 months and 5-7% after 6 months. But many patients report losing even more weight than this. To put that in context, a 5-7 percent weight loss equals 10-14 pounds for a 200-pound person. This medication, however, does not work for everyone. If you haven't lost much weight after three months, your doctor may advise you to stop taking the medication and adopt another weight loss strategy.