I've had a fever come and go for over 6 months. I was trying to find out why, and then I came across this weight gain which was by chance. I was put on synthroid in 2004 because of unexplained weight gain they found I had this thyroid problem. Since then, I have gained 60 lbs, even through battling renal cell carcinoma (Kidney Cancer) , and lap band surgery. I can't believe all my complaining, and not one doctor told me this pill causes weight gain. This makes me quite angry. D.