Objective　The study aimed to verify the efficacy on knee joint and safety of dietary supplement containing Proteoglycan complex 80 derived from salmon nasal cartilage.
Methods　A randomized, double-blind, placebo-controlled, parallel-group study was conducted for 60 participants（51.7±6.9 years）who ingested dietary supplement containing 40 mg of Proteoglycan complex 80 produced from salmon nasal cartilage or placebo for 12 weeks. The Japanese Orthopaedic Association（JOA）score, Japanese Knee Osteoarthritis Measure（JKOM）score, Knee Society Score（KSS）, and Visual Analogue Scale（VAS）questionnaire were used for evaluation of knee joint function.
Results　The JOA and JKOM scores, KSS and the results of VAS questionnaire were significantly improved between dietary supplement and placebo after 12 weeks. Side effects related to intake of Proteoglycan complex 80 were not confirmed on this study.
Conclusion　These results strongly suggest that the dietary supplement containing Proteoglycan complex 80 from salmon nasal cartilage is effective for improving knee joint functions and safe.