Qsymia, the first of the four new weight-loss drugs to be approved, fared best in promoting the loss of 5 percent of body weight in patients taking it. A median of 75 percent of those taking Qsymia lost 5 percent of their body weight, while a median of 63 percent of participants taking Saxenda and 55 percent of those taking Contrave did. A median of 49 percent of participants taking Belviq and 44 percent of those taking the over-the-counter medication Alli succeeded in losing 5 percent of their body weight in the trials. A median of 23 percent of those on a placebo pill lost 5 percent of their weight.