Very interesting. Some researchers and physicians believe low ATP production plays a role in FM and CFS. This could be due to problems with the mitochrondria or perhaps more likely to mitochondrial injury due to increased oxidative stress levels from low blood flows or some other reason. Nobody really knows but it is clear that some FM and CFS patients do benefit from these mitochondrial enhancers. For more on D-Ribose and CFS - much of which may apply to FM - paste the URL below into the address bar at the top of the page. (Sorry I wasn't able to make it clickable!) http://phoenix-cfs.org/TrtD-Ribose.htm