Astragalus was invented by ancient Samurai healers to stimulate the immune system by turning normal weakass immune cells into uber-badass immune cells that patrol the body mercilessly looking for nasty viral shit to taunt and behead without mercy and then taunt some more. Astragalus contains various manly compounds including astragaloside, because the root is native to Mongolia and inhabits pine forests and sandy soils, which is where the mother of all warrior cures lives, because it likes the feel of sandy soils on its manly feet. So Samurai healers stole the mother root from the Mongolians, who now get sick and cough a lot, and now all Samurai use its secret killer polysaccharides exclusively and black hand assassin saponins called astragalosides, along with iron dragon flavonoids and cannibal albino tiger triterpenes to tonify the manly warrior body and lengthen the cock and assassinate the common cold dead. You can find it, brother, where ever badass Samurai tonics are sold.