Guaifenesin
"I'm not sure how long I've had fibromyalgia, but I'm guessing about 10 yrs. The fatigue/widespread pain and depression were so bad I couldn't stand it any longer. I had read about Mucinex online, but I couldn't fathom how this could possibly help me. One day while trying to work, I just couldn't stand it. I couldn't concentrate, much less keep my eyes open and the pain -- I couldn't move anything without the pain. So I walked across the street to the store and picked it up. I was very desperate. I was literally SO shocked by what happened. Within 30 minutes, the pain wasn't severe and for the first time since I can remember I didn't feel that debilitating fatigue.  I told everyone that would listen. It's been miracle for me."