Dried and sliced thin, the root of the astragalus plant is a common component of Chinese herbal formulas. According to tradition, astragalus "strengthens the spleen, blood, and Qi; raises the yang Qi of the spleen and stomach; and stabilizes the exterior." ^ Don't worry if you didn't understand what you just read, because without many months of training in traditional Chinese herbal medicine , there's no way you could have. Suffice it to say that the traditional understanding of the way astragalus works is different from the way it tends to be presented today.
A typical daily dosage of astragalus involves boiling 9 to 30 g of dried root to make tea. Newer products use an alcohol-and-water extraction method to produce an extract standardized to astragaloside content, although there is no consensus on the proper percentage.
What Is the Scientific Evidence for Astragalus?
Although Chinese herbal tradition suggests that astragalus should generally be used in combination with other herbs, modern Chinese investigators have found various intriguing effects when astragalus is taken by itself. Extracts of astragalus have been found to stimulate parts of the immune system in mice and humans, and to increase the survival time of mice infected with various diseases. ^ Astragalus has also been shown to enhance diuresis (urine output) by encouraging the kidneys to release more sodium into the urine. ^ Other highly preliminary research suggests that astragalus might be useful in treating atherosclerosis , hyperthyroidism , hypertension , insomnia , diabetes , chronic active hepatitis , genital herpes , AIDS , and increase the efficacy and/or reduce the side effects of cancer chemotherapy . ^ However, none of these possibilities can be regarded as proven.