Another anecdote. Gluc/Chon has helped my knee pain. That as well as all of my running/cycling/CrossFit - combination therapy.
Like you Ridebikeme, if I forget the supplement for a couple of days, the knees complain. It does absolutely nothing for my back pain (which is prloapsed disc every now and then) and nothing for supraspinatous (currently driving me nuts). But my knees are telling me they are very happy. Like Knot says- if it works, it works.
"You can't get what you want till you know what you want." Joe Jackson
2006 Cannondale Feminine/Ultegra/Jett
2012 Trek Speed Concept 9.5/Ultegra/saddle TBD