My 7 year old Lab/Australian Shepard mix has been having hip/joint issues (also a bit overweight).  She's been on this two month now, and I have noticed a definite improvement in my hip/joint issues.  She's much more perky and playful again, will run, jump for hugs, and just generally is happier!  And all of this has helped to contribute to some exercise for weight loss.  Highly recommend!