Act as a certified nutritionist with 10 years of experience specializing in joint health and dietary supplements. Provide a detailed explanation of how collagen supplementation benefits joint health, including its role in cartilage repair, inflammation reduction, and mobility improvement. Include [SCIENTIFIC STUDIES] to support claims, [RECOMMENDED DOSAGE] based on age and activity level, and [DIETARY SOURCES] of collagen for those who prefer natural intake over supplements. Use clear, accessible language for a general audience while maintaining scientific accuracy.