**5. Conclusions**

Four weeks of CIT+GSH supplementation improves brachial artery FMD in apparently healthy postmenopausal women with slightly elevated FBG. CIT+GSH reduced brachial PWV and attenuates BP responses to sympathetic activation. These beneficial effects on the endothelial function and BP reactivity may be attributed to an increased ARG/ADMA ratio. Therefore, CIT+GSH supplementation may reduce the risk of cardiovascular events during physiological stress in postmenopausal women. Although CIT supplementation alone caused greater increases in the serum ARG levels and ARG/ADMA ratio, it did not improve FMD or BP responses to CPT in healthy postmenopausal women.

**Author Contributions:** A.F., M.M. and D.N. were responsible for the study design. A.F. was responsible for the conduction of the study. A.M., S.M.F., M.A.M., Y.K. and K.N.D. performed the experiment and data collection. A.F., A.M., S.M.F., M.A.M., Y.K. and K.N.D. participated in the data analysis and interpretation. A.F., M.A.M., Y.K. and K.N.D. wrote the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was funded by Kirin Holdings Co., Ltd., grant A20-0164-001.

**Institutional Review Board Statement:** The experimental protocol and informed consent was approved by Texas Tech University Institutional Review Board.

**Informed Consent Statement:** Written informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** The data presented in this study are available upon request from the corresponding author.

**Acknowledgments:** The authors recognize the cooperation and enthusiasm of our participants.

**Conflicts of Interest:** M.M. and D.N. are employees of Kirin Holdings Co., Ltd. M.M., D.N. and Kirin had no influence on participant handling, data collection, analysis or interpretation, and manuscript writing. The other authors declare no conflict of interest.
