Joint supplements are widely used for dogs with arthritis, with varying levels of evidence for different ingredients and welfare implications for dogs who may receive inadequate treatment as a result.
The welfare concern with over-reliance on joint supplements is displacement of effective pain management. Dogs with osteoarthritis who receive only glucosamine/chondroitin instead of appropriate NSAIDs or newer pain medications are likely experiencing ongoing pain that effective treatment would relieve. The marketing of supplements as adequate pain management for arthritic dogs is a welfare problem when it leads owners to believe their dog's pain is being addressed when it is not. Supplements may have a role as adjuncts but should not substitute for evidence-based pain management, particularly in dogs with moderate to severe arthritis.