It seemed to help Alice for a long time, although hard to tell. After trying various ones, I used to buy Corta-Vet, which is double-strength Cortaflex. It comes in drops and sprinkle capsules. It claims to contain the active isolates of glucosamine etc, so apparently works better. It also contains hyaluronic acid. I used it for several years, then switched to Stride Plus for cats, which seems to be similar (but cheaper), although hard to tell if it is.