Ginseng is the root of two different herbs from opposite sides of the world, American ginseng (P. quinquefolius) and Asian ginseng (P. ginseng). American ginseng is wild-harvested and grown in eastern North America. Asian ginseng, which includes both Korean and Chinese ginseng, is cultivated in China, Korea, and Japan.
According to the Harvard University botanist Shiu Ying Hu, the earliest mention of ginseng is in the 2,000-year-old herbal of Shen Nong:
It is used for repairing the five viscera, quieting the spirit, curbing the emotion, stopping agitation, removing noxious influence, brightening the eyes, enlightening the mind and increasing wisdom. Continuous use leads one to longevity with light weight. Ginseng use has changed little in 2,000 years.
In the last thirty years, Asian ginseng (but not American ginseng) has been extensively studied. Like eleuthero, ginseng is an adaptogen. At least seven European clinical studies showed that standardized extracts decreased reaction time to visual and auditory stimuli; increased respiratory performance, alertness, power of concentration, and grasp of abstract concepts; and improved visual and motor coordination. Sometimes conflicting results indicate the need for further clinical studies, especially on products with well defined levels of active compounds.
Recent studies have focused on antiviral and metabolic effects, antioxidant activity, and effects on nervous and reproductive systems.
Ginseng is also a nonspecific immunostimulant similar to echinacea. There are more than eighteen active chemicals called ginsenosides in Asian ginseng. American and Asian ginsengs contain some of the same as well as some different ginsenosides which explains their different actions as expressed in traditional Chinese medicine (TCM). Mild American ginseng helps to reduce the heat of the respiratory and digestive systems, whereas the stronger Asian ginseng is a heatraising tonic for the blood and circulatory systems.
In Germany, Asian ginseng products may be labeled as tonics to treat fatigue, reduced work capacity, lack of concentration, and convalescence.
Asian ginseng is available as whole root, powder, and in various forms including "white" and "red" ginseng. White ginseng is simply the dried root; translucent, rust-colored "red" ginseng is made by steaming the roots for three hours, then drying them; it is considered stronger than white ginseng. Product forms include tinctures, capsules, tablets, teas, and extracts. Asian ginseng products standardized to contain 4-7 percent ginsenosides are widely sold and may produce more reliable effects than other forms. American ginseng is generally available as the whole or powdered root.
Use at normal dosage levels is Generally not associated with side effects; however, some persons have experienced overstimulation or gastrointestinal upset and some women have reported breast tenderness or menstrual problems with long-term use. If you have high blood pressure, use ginseng with caution. Avoid ginseng during pregnancy.