Cardiovascular and cerebrovascular diseases are most terrible killers endangering the health of Chinese residents, and hypertension is the most important risk factor. Hypertension related microvascular rarefaction and endothelial dysfunction are the common pathological basis and initiation of cardiovascular and cerebrovascular disease. Therefore, reducing blood pressure and delaying or reversing endothelial dysfunction is an effective way to treat hypertension and prevent cardiovascular disease. Alpha-ketoglutarate (αKG) is a critical metabolic intermediate in the tricarboxylic acid (TCA) cycle, involves in diverse cellular biological activities, such as central metabolism, antioxidative defense, epigenetic regulation, and cell proliferation. The latest research found that with the growth of age, the level of αKG is decreasing, and increasing the content of αKG can prolong the life of multiple species including human. Recent clinical trials found that αKG supplementation can effectively improve the level of αKG in cells, delay aging, improve the metabolic process of cells without adverse reactions. However, the effect of αKG supplementation on reducing blood pressure and protecting vascular endothelial function has not been reported. Therefore, this study aims to focus on hypertension, a major chronic disease, and to observe the effects of αKG supplementation on endothelial function and blood pressure in patients with hypertension, so as to provide a new treatment strategy for hypertension and associated endothelial dysfunction.