Did glucosamine put a spring in my old cat’s step?

Our family’s beloved cat of 20 years, Matu, doesn’t move nearly as fast as he used to (no more chipmunk chasing in our yard here in Vermont). It was obvious that his joints hurt. My vet had previously told us that Matu (pictured) had arthritis in his back legs, and had even offered some glucosamine, a dietary supplement that is also taken by humans. But I politely declined, feeling that there was enough going on medically in our old feline as it was (I squirt a milliliter of thyroid medication down his throat every evening). I didn’t think having one more thing tossed down his gullet each night would improve his quality of life.

But a few weeks ago my vet made a house call to check on Matu and we mentioned that the arthritis had been worsening—so much so that he’d become hesitant to make the trip downstairs to the basement where the litter box was. So, too, had it become difficult for him to make the lengthy trek upstairs to the second-floor bedrooms; the sound of his climbing stairs had become a hobbling "ker-plump, ker-plump" rather than his earlier fleet-footed gallop. This time, the vet sold us on a small bottle of 90 capsules containing a combination of glucosamine and chondroitin. We were to break the capsules open and sprinkle the contents on Matu’s food once a day.

So I decided to put it on his food, quite sure that a.) he’d eat less of the food because of the powdered substance on it, and b.) he thus likely wouldn’t get nearly enough of the powder for us to see if it really made any difference. He proved me wrong, and by the next morning had consumed practically all that was in his bowl. He also seemed a bit more chipper and light-footed. Still, I thought, I was digging for a benefit when clearly it was too early to see one.

After Matu had another nightly dose sprinkled on his food, the following morning my wife and I were startled to hear him move up and down the stairs quite quickly, with much less of that "ker-plump, ker-plump" sound. A couple of days later now, there's no mistake about it—he’s livelier, with no real hesitation in his step. But how could this be so evident so quickly, after just a few doses of the stuff? The researcher in me wants to let this little trial run for another week or so and then stop with the supplement and perhaps sprinkle some nutritional yeast on his food for a week or two just to see what happens. But I know I couldn't do that. I'm not that cruel. He’s now more willing to be petted around his back legs, which he absolutely couldn’t tolerate before. And that’s definitely a big improvement.

—Chris Hendel, associate director, Consumer Reports Health

Have you had similar success in giving these supplements to your older cat or dog? Or was your experience not so good? We’d like to hear about it either way. Also, visit our new pet products and advice page .

—Aaron Bailey