I have a chihuahua with a back injury/arthritis. Gluco/chondro products tore up his stomach, and he refused to eat them...understandably, since they made him sick. I tried HA, since it works on my horses. Sure enough, within 3 days he suddently leapt up on the couch!! It had been years since he had done that!! The HA just goes on his food, but I did have to add extra water since HA is hygrophilic, and it appeared to constipate him. More water did the trick.