Fido-Vite K-9 Supplement and Fido-Flexx are the same product for the exception of glucosamine and chondroitin. Fido-Flexx has glucosamine and chondroitin and Fido-Vite K-9 Supplement does not. Fido-Vite SportzDog is designed primarily for working and show dogs, but also will have added health supporting benefits for reproduction, puppies and some older dogs primarily due to increased levels of omega-3 fatty acids. Fido-Vite SportzDog has higher levels of glucosamine and chondroitin, minerals, vitamins and L-Carnitine as well.