The FDA found Teva's generic to be bioequivalent and therapeutically equivalent. http://www.fda.gov/AboutFDA/CentersOffices/OfficeofMedicalProductsandTobacco/CDER/ucm153270.htm?utm_campaign=Google2&utm_source=fdaSearch&utm_medium=website&utm_term=generic%20Wellbutrin%20Xl%20teva&utm_content=1 That's good enough for me.