American ginseng is similar enough to Asian ginseng to chemically have the same effects.
American ginseng root is light tan and looks a bit like a human body. Herbalists hundreds of years ago took this likeness to mean that ginseng could cure all human ills. It has been used as a cure-all by many different cultures. Ginseng is difficult to grow. This difficulty made it a good export crop early on in American history, because it was plentiful in North America.