For more than 2000 years, Chinese herbalists have valued Astragalus for its adaptogenic properties, as well as for its ability to tonify the body's "vital force" known as the Qi. More recently, Astragulus has been found to support healthy immune function through numerous mechanisms. Non-clinical studies using Astragalus have demonstrated its ability to stimulate the production of and increase the activity of specialized white blood cells, such as T-Cells and Natural Killer Cells. Astragalus has also been studied for its role in the support of healthy liver and vascular function. Herbalists recommend the use of Astragalus both seasonally and year-round to support a healthy Defense mechanism of body.