I think I have tried everything. Everytime I read about something that might help I give it a shot. So far for me, the only thing that seems to have made a difference is SAMe. I don't believe that it really does anything to improve things though. I think that it just helps with the pain. I am not sure on that though. I also "think" that geletin might help. The trouble with that stuff is that it takes 3 months to do anything. Knox makes a geletin supplement, and there are a few others out there. Knox is probably the easiest to find. Bromelain is something that I am just starting on, but I have been told that it is good. Who knows?
Also, I have a Border Collie mix dog that has trouble. She gets to try everything as well. I call the vet and get the dosage adjusted for her. I figure that if I see a difference in her, it can't be a placebo thing because she has no idea what she is taking or why. So far, the SAMe and Bromelain seems to have helped the most. She is also taking a Glucosomine supplement that seems to help, but you can't take that. I only change one thing at a time with her so that I know what is and is not working.
Good luck in your searches! If you find anything interesting out let me know. i will try anything that won't make me sick.