I started both my dogs, cockapoo (10) and terrier cross (8) on Antinol because it contains PCSO-524 - to safeguard them as prevention is better than cure. I want to keep their joints as mobile as possible as they get older. My terrier cross is 8 and already had problems with his luxating patella. He hasn't limped ever since we have started him on Antinol. Being proactive about making sure their joints stay healthy gives me peace of mind.