I have been giving Molly this for over 6 months now and I like that it is easy to use since it contains most of the key ingredients for joint health including hyaluronic acid:
http://liquidhealthpets.com/k9-level-5000I have tried a few other things in the past but this one is the most convenient (for getting my BF to add it to her food when he does feedings). BF isn't the best about adding supplements to Molly's food and our feeding schedule is such that he does the evening feeding.
I'm not sure if I really see a huge difference (I have held off giving it to her for several days before to see if there is any change). She has already had surgeries to fix both knees (both were partial CCL tears) and she is around 5 years old right now and healthy aside from some mild allergies. She has also had hip, elbow and spine x-rays done in the past couple of years and there is no indication that we need to worry about any of those parts but I feel preventative maintenance can't hurt.