Undenatured Type II Collagen for Knee Osteoarthritis Pain

This randomized, controlled, double-blind, three-arm parallel clinical trial will evaluate the efficacy and safety of undenatured type II collagen products on joint pain in adults diagnosed with knee osteoarthritis. Participants will be randomized to Nuvicol II, Nuvicol SII, or placebo and will consume one capsule daily for 4 months. Pain, quality of life, knee muscle function, concomitant analgesic medication use, cartilage degradation biomarkers, safety laboratory variables, and adverse events will be assessed during follow-up.

Inclusion Criteria: * Age over 30 years. * Subjects diagnosed with osteoarthritis with functional grades I-III according to the modified American College of Rheumatology criteria. * Persistent knee pain associated with osteoarthritis with a baseline VAS pain assessment score of at least 30 mm. * Subjects must not have narcotic or steroidal anti-inflammatory drugs or immunosuppressants in their treatment. Exclusion Criteria: * Serious or terminal illnesses. * Allergy or hypersensitivity to any component of the product under study. * Vegan or vegetarian diet. * Current use of glucosamine, chondroitin sulfate, collagen, hyaluronic infiltrations, or any supplement indicated for joint health. * Chronic inflammatory diseases affecting the musculoskeletal system, including rheumatoid arthritis, gout, pseudogout, Paget disease, or chronic pain syndrome. * Body mass index above 32 kg/m2. * Participation in any other research during the last 3 months. * Pregnant, planning pregnancy during the study, lactating, or breastfeeding. * Biological childbearing potential without continuous effective contraception as determined by the investigator. * Inability to understand the research study.