I've been taking some stuff called "move free" for about 2 months now. My knees that I beat up on skateboards and the wrestling mats in high school haven't felt this good in years. I tried other glucosamine stuff but didn't get anything other than a lighter wallet. At least glucosamine is basically 100% safe from everything I've read so if you try it for a while, shouldn't be any problems if it doesn't give you any benefits.