Alpha-cyclodextrin supplementation improves endurance exercise  performance and reduces  post exercise fatigue  in human males.  a randomised, double blind  placebo controlled paralell group study 

It huas been recently reported that αCD supplementation for eight weeks in nonathlete men improved the 10 km biking time compared with that in a placebo group [1], suggesting that ingesting αCD may affect endurance exercise performance. A randomized, double-blind, placebo-controlled, parallel-group study [2] was conducted to confirm the reproducibility and obtain additional data, employing a larger sample size and a greater αCD dose than that used in the previous study. Age, body mass index, estimated V̇O₂ max, and Bacteroides uniformis cell number in feces were used as stratifying factors. Eighty-one healthy nonathlete men aged 20 to 49 years who had exercise habits received a placebo (n=42) or αCD (1 g/day; n=39) for 9 weeks. 

The study confirmed that supplementation with αCD for eight weeks improves 10-km biking performance and found that supplementation with αCD reduces post-exercise fatigue and suppresses the heart rate increase during exercise in men with existing exercise habits. Given the global interest in health and wellness, many supplements are incorporated into daily life, some of which may be effective for exercise performance and fatigue. αCD is prevalent as a food additive, is regarded as a safe substance, and does not require a specified upper limit of intake by the Joint FAO/WHO Expert Committee on Food Additives. Therefore, our findings suggest that αCD may be used as a safe supplement to maintain or improve endurance exercise performance and reduce post-exercise fatigue.

References

1. Morita H, Kano C, Ishii C, Kagata N, Ishikawa T, Hirayama A, Uchiyama Y, Hara S, Nakamura T, Fukuda S. 2023. Bacteroides uniformis and its preferred substrate, α-cyclodextrin, enhance endurance exercise performance in mice and human males. Sci Adv 9: eadd2120. 
2. Onishi M, Nakamura T, Kano C, Hirota T, Fukuda S, Morita H. α-Cyclodextrin supplementation improves endurance exercise performance and reduces post-exercise fatigue in human males: a randomized, double-blind, placebo-controlled, parallel-group study. Biosci Microbiota Food Health. 2025;44(1):80-89. doi: 10.12938/bmfh.2024-062.