Voltorol was pretty good for very bad Osteo after i dislocated my hip in a car RTA. It didnt work for ever though, as i had to have a new hip.
The other stuff is Glucosamine. I cant say whether this stuff works for everyone, but it worked for my dog. She had a bad limp after running around, and it showed up more after she had rested and couldnt stand on one of her back legs for 30 seconds or so until it eased off. Vet diagnosed a problem with the joint in her rear knee.
She started on expensive vet prescribed drugs, one of which made her a bit sick, so i did some extensive research online for a more natural medicine. This was 25 years ago-ish, and i discovered Glucosamine was a thing for people. I sourced some from a company called Healthspan in Jersey. I weighed my girl, and reduced the Glucasomine accordingly. Within 3 months, i couldnt tell she had arthritis, it was that much of a revelation. She stayed on Glucosamine for the rest of her life