Understand the benefits of WELLBUTRIN XL®, its unique SmartCoat™ technology, and the differences between brand name and generic versions. Learn how to ensure you receive the brand name medication at the pharmacy. Wellbutrin XL and Wellbutrin SR are different formulations of the antidepressant bupropion. Both Wellbutrin XL and Wellbutrin SR may cause weight gain or weight loss, but weight loss is more common. The official site for WELLBUTRIN XL® provides information for healthcare professionals on clinical experience in Major Depressive Disorder (MDD) and Seasonal Affective Disorder (SAD). Find patient medical information for Bupropion (Wellbutrin, Zyban, and others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings What is Wellbutrin XL? Wellbutrin XL is a prescription medicine used to treat adults with a certain type of depression called major depressive disorder. Wellbutrin XL contains the same active ingredient (bupropion hydrochloride) as Zyban. Zyban is used to help people stop smoking. Wellbutrin (bupropion) is used to treat major depressive disorder and seasonal affective disorder. Includes Wellbutrin side effects, interactions and indications. Wellbutrin XL (Bupropion Hydrochloride Extended-Release) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources.