First of all, weight loss is the result of a proper diet and exercise routine. There's no way around that fact. Fat burners are simply an additional "oomph" in the right direction. Generally speaking, if you cut 500 calories from you diet and keep everything else the same, you'd lose about one pound per week. If we assume fat burners help you burn an additional 100 calories per day, then you'd lose about one extra pound every five weeks. So, over the course of a year, they might help you drop an additional 10 pounds, assuming your diet and exercise routines align with these goals.