If you want a minor clinical "anecdotal study" (
) our two boys, Cole and Ember, have been on it since about the age of 18 months, I believe, since both have some elbow abnormalities. There has been, as far as we can tell, no longterm side effects to the glucosamine/chondroitin after 10 years.
That's not to say there couldn't be, but we haven't seen any.