After separating my shoulder in football, I always used to have a slight ache in my shoulder. This led me to search for a good joint aid supplement. While there are a few that do work, nothing works as well as animal flex from universal nutrition. Its night and day with flex. I honestly recommend this to everyone who is lifting a good amount of weight. it not only helps aches, but prevents as well. I noticed extreme comfort in my knees when squatting as well.