Recently I was switched from Zydus bupropion xl to a Mylan brand… I agree with all other opinions I have read… It is horrible. Now I know why I have been feeling so bad and now feel so good. I also didn't feel that this medicine was doing anything for me. Today I decided to look Zydus up and compare it to Mylan to see the difference and I am glad I did. I am not getting headaches, sleeping better and mood swings gone. I also was feeling off balance, but not any longer.