Glucosamine Condroiten?

I am in my 50s and use glucosomine chondrotin on myself as well as for my 12 year old sheltie. I think it gives both of us small but noticeable result. Nothing amazing but I can feel some difference and I think the dog can too. My dog is kind of slow when he first gets up but after he is up a few minutes, he is reasonably energetic, still climbs stairs and will run and play with the younger dog for a while. But shelties are long lived breed with few arthritis or dysplasia issues. I have been giving it to the dog for 2 or 2 1/2 years and I have not noticed any negative side effects. I know for myself, I need to take at least 3 weeks before I notice a difference. I asked the vet about it a couple of years ago and he says it is fine to give it to the dog and some dogs have more of an effect with it than others. My personal opinion is it works better for mild to moderate aging/arthritis and less for hip dysplasia but that is just my opinion, not the vet's.