@teddy69 - I have taken Mucinex extended release for 40 years (Yes, 40) - even before my fibromyalgia diagnosis, because I have thick mucus everywhere - sinuses, lungs, even ear fluid. At one point my pulmonologist suggested I try to stop it to "see if it is really helping" and not only did my lungs get worse, so did my fibro pain and my arthritic joint pain. So for me, the answer is yes, it does seem to help.

I take real Mucinex long-acting (pure guaifenesin extended release) twice a day. I tried cutting to once a day, and felt worse. I buy it on line in bottles of 500 tablets to cut the cost, and watch for sales. The generics were too uneven in their quality for me, and the short-acting was a pain because I needed to use it 4 times a day.

Just one person's experience. I often wonder if my consistent use of Mucinex was one of the things that enabled me to plod along and keep working through years of fibromyalgia and arthritis. My pain rehab doc thought that might be the case.