I started taking SynFlex awhile back. It is tough to decide if it is helping me or not since I had surgery on Nov 6. I can tell you that it made a tremendous difference with my 11 year old border Collie / Austrailian Shepherd Kelly. She had been on some powder stuff from the vet. It was expensive and seemed to make no difference. Kelly climbed several 14,000 ft mountains after being on it for a few months. She would not have been able to do that prior to then. She also was much less stiff and sore the day after.