This study examined 21 nutritional supplements, taken daily for durations ranging from a few weeks to several months.

Curcumin (80 mg/day) improved the FEV1 (the amount of air a person can forcefully exhale in the first second of a breath) by 13%, probiotics improved it by 7.1%, and butyrate by 2.7%.

Coenzyme Q10 plus creatine increased the 6-minute walk distance by 63 meters, nitrate increased it by 30 meters, and whey protein by 11 meters.

Melatonin and Yam-Epimedium (a Traditional Chinese Medicine mixture)^[1] each improved shortness of breath, and taking melatonin, vitamin D, whey protein, and Yam-Epimedium together improved the quality of life.

The quality of the evidence was moderate for lung function outcomes and low for others.

Supplements for improving COPD outcomes — Which ones really work? Original paper