What Is Ginseng?

Ginseng has been used as a cure-all since ancient times. It contains many active compounds, including more than 40 different ginsenosides, thought to be the plant’s main active ingredients. There are several types of ginseng. Asian ginseng (Panax ginseng C.A. Meyer)—often sold as Korean, Chinese, or Panax ginseng—is grown in eastern Asia. American ginseng (Panax quinquefolius) is native to North America. Ginseng also comes as red or white ginseng, depending on how it’s processed. Siberian ginseng (Eleutherococcus senticosus) is often said to have the same effects as Panax ginseng, but it is not a true ginseng. It and other similar plants may be used in products as a cheaper substitute.

Claims, purported benefits: Acts as an “adaptogen,” boosting the body’s resistance to physical and mental stress, increasing energy and enhancing general well-being. Prevents or treats everything from colds, diabetes, digestive problems, and menopause symptoms to poor circulation, asthma, memory problems, and even HIV infection and cancer. Also an aphrodisiac. What the science says: Ginseng is one of the most researched herbs. Compounds in ginseng have immune-enhancing, anti-inflammatory, antioxidant, and anti-cancer properties. They may also relax blood vessels, help protect the nervous system, affect hormones, and improve blood sugar, among other effects.

Still, ginseng’s potential medicinal effects remain unclear. One problem is its variability. Different types of ginseng have different compounds and biological properties, and different parts of the plant (roots, leaves, stems) also contain varying chemicals. How ginseng is processed affects its biological activity as well. Most studies have been small and/or poorly designed and have used different formulations and doses of ginseng, making them hard to compare. It’s difficult to study the many vague claims.

Diabetes. Several small studies have found that ginseng can help control blood sugar. The Natural Standard gives ginseng a “B” rating (good evidence) for its effect on blood sugar in people with type 2 diabetes, but notes that its long-term effectiveness and safety are unclear. In a small study in the Asia Pacific Journal of Clinical Nutrition in 2013, however, overweight people without diabetes did not have improved insulin sensitivity after taking Korean red ginseng for 12 weeks.

Immunity. There’s B-grade evidence that ginseng boosts the immune system, according to the Natural Standard. A small Canadian study in 2008, for example, found that North American ginseng increased immune markers in sedentary men who did a short bout of cycling.

Colds. A few preliminary studies suggest that Cold-fX, a patented standardized extract of North American ginseng, may help reduce the frequency and severity of colds (and flu) when taken twice daily throughout the winter, a claim allowed by Health Canada, which functions like our Food and Drug Administration. There’s no evidence that it can provide relief once you have symptoms, though marketers have sometimes claimed or strongly suggested this. In the U.S., Cold-fX is available only online.

Brain health. Though some review articles also cite potential cognitive benefits, they note that there is a scarcity of good-quality data. In 2010, the Cochrane Collaboration concluded there is “no convincing evidence of a cognitive-enhancing effect of Panax ginseng” in healthy people or those with memory problems or dementia. A 2014 review in Nutrition Reviews concluded that the evidence “suggests ginseng has potential, but unproven, benefits for cognition.”

Other uses. A 2013 Egyptian study in the Global Journal of Pharmacology found that Asian ginseng lowered LDL (“bad”) cholesterol by about 15 percent in people with high blood cholesterol. Preliminary research, including a Korean study in 2012, suggests that ginseng may improve erectile dysfunction; other forms may not have this effect. Some athletes use ginseng, but studies have generally found no effect on physical performance. There’s no convincing evidence ginseng can treat or prevent high blood pressure, cancer, or any other condition.

Common side effects: Ginseng may interact with anti-clotting medication as well as drugs taken to control blood sugar (such as insulin) and certain antidepressants. It should be used with caution in people with high blood pressure or those taking medications that affect blood pressure. A 2010 analysis by ConsumerLab.com found that several supplements didn’t have the full amount of ginseng listed on the label, and there was also great variability in ginsenosides among the products. Plus, some products were contaminated with lead and pesticides.

Our advice: It’s hard to evaluate ginseng. How it’s typically studied and used in the West (as a single herb in a purified extract) is not how it’s traditionally used (in its whole form and often in combination with other herbs). Still, overall, the studies don’t show clear or conclusive benefits. The best evidence is for its effect on blood sugar, but if you have diabetes you should not use ginseng in place of proven therapies.