Experts had voiced safety concerns on the drug, but determined the benefits outweigh the risks.
Studies show patients taking the drug lost 4.2 percent more weight than those taking a placebo.
But there is concern about Contrave's possible side effects, including high blood pressure, dizziness and insomnia.
Scientists are also concerned about the drug's possible effect on the heart.
The FDA is not required to follow the advice of its expert panels, but often does. The agency is scheduled to make a decision on Contrave by Jan. 31.
Physicians and health officials have said weight-loss therapies are needed because of the rising obseity rates among adults in the U.S. But the search for that treatment has been fraught with safety issues.
The Associated Press contributed to this report.