knees

I'm looking for the best supplement to help with my injuries my knees don't feel that good and when I workout I get a cracking noise coming from them do you think it means that my knees are too dry and need to be lubricated?

This is pretty funny but when I was using the smith machine today I felt my joints cracking in my knees I racked the weights and then went and sat down and did some stretching which supplement would work good here?