Subjects and methods: Thirty-five stable COPD patients who were undergoing pulmonary rehabilitation were divided into the supplemented group and the non-supplemented control group in an open-label controlled trial. Of the 35 patients, 23 were included in per protocol set analysis. Primary outcomes were levels of the systemic inflammatory markers TNF-α, IL-6, IL-8, and CRP and the nutritional marker serum albumin. Secondary outcomes were transthyretin level, transferrin level, body composition, respiratory function, respiratory muscle strength, 6-minute walk-test distance, muscle strength, and quality of life (QOL).