Fenfen was rushed to market and we didn't really learn about the health effects of Fenfen until people started dying. One short term study of a small group of adolescents does not tell us that this is safe or effective for most kids. Pharmacotherapy alone has not proven to be an effective obesity treatment. Medication used as part of a structured lifestyle modification produces an average weight loss of five to 10%, which typically plateaus at four to six months of therapy, after which weight regain may occur.