Asian ginseng (Panax ginseng) has traditionally been used as a supportive herb for male potency. A double-blind trial found that 1,800 mg per day of Asian ginseng extract for three months helped improve libido and the ability to maintain an erection in men with ED.¹⁶ The benefit of Asian ginseng confirmed in another double-blind study, in which 900 mg three times a day was given for eight weeks.¹⁷

Asian ginseng may prove useful for male infertility. One preliminary study found that 4 grams of Asian ginseng per day for three months led to an improvement in sperm count and sperm motility.¹⁸

Asian ginseng (Panax ginseng) has traditionally been used as a supportive herb for male potency. A double-blind trial found that 1,800 mg per day of Asian ginseng extract for three months helped improve libido and the ability to maintain an erection in men with ED.¹⁹ The benefit of Asian ginseng confirmed in another double-blind study, in which 900 mg three times a day was given for eight weeks.²⁰

Herbal supplements can help strengthen the immune system and fight infections. Adaptogens, which include eleuthero, Asian ginseng, astragalus, and schisandra, are thought to help keep various body systems—including the immune system—functioning optimally. They have not been systematically evaluated as cold remedies. However, one double-blind trial found that people who were given 100 mg of Asian ginseng extract in combination with a flu vaccine experienced a lower frequency of colds and flu compared with people who received only the flu vaccine.²²

Asian ginseng and eleuthero (Siberian ginseng) have immune-enhancing properties, which may play a role in preventing infection with the influenza virus. However, they have not yet been specifically studied for this purpose. One double-blind trial found that co-administration of 100 mg of Asian ginseng extract with a flu vaccine led to a lower frequency of colds and flu compared to people who just received the flu vaccine alone.²³

Herbs that support a person’s immune system in the fight against microbes include the following: American ginseng, andrographis, Asian ginseng, astragalus, coriolus, eleuthero, ligustrum, maitake, picrorhiza, reishi, schisandra, and shiitake.

Immune-modulating plants that could theoretically be beneficial for people with HIV infection include Asian ginseng, eleuthero, and the medicinal mushrooms shiitake and reishi. One preliminary study found that steamed then dried Asian ginseng (also known as red ginseng) had beneficial effects in people infected with HIV, and increased the effectiveness of the anti-HIV drug, AZT.²⁴ This supports the idea that immuno-modulating herbs could benefit people with HIV infection, though more research is needed.

The Chinese herb bupleurum, as part of the herbal formula sho-saiko-to, has been shown to have beneficial immune effects on white blood cells taken from people infected with HIV.²⁵ Sho-saiko-to has also been shown to improve the efficacy of the anti-HIV drug lamivudine in the test tube.²⁶ One preliminary study found that 7 of 13 people with HIV given sho-saiko-to had improvements in immune function.²⁷ Double-blind trials are needed to determine whether bupleurum or sho-saiko-to might benefit people with HIV infection or AIDS. Other herbs in sho-saiko-to have also been shown to have anti-HIV activity in the test tube, most notably Asian scullcap.²⁸ Therefore studies on sho-saiko-to cannot be taken to mean that bupleurum is the only active herb involved. The other ingredients are peony root, pinellia root, cassia bark, ginger root, jujube fruit, Asian ginseng root, Asian scullcap root, and licorice root.

The herbs discussed here are considered members of a controversial category known as adaptogens, which are thought to increase the body's resistance to stress, and to generally enhance physical and mental functioning.^29,30 Many animal studies have shown that various herbal adaptogens have protective effects against physically stressful experiences,^31,32 but whether these findings are relevant to human stress experiences is debatable.

Animal studies support the idea that Asian ginseng is an adaptogen.³³ Some studies have suggested that Asian ginseng can enhance feelings of well-being in elderly people with age-associated memory impairment,³⁴ nurses working night shifts,³⁵ or people with diabetes.³⁶ In a double-blind trial, people taking a daily combination of a multivitamin-mineral supplement (MVM) with 40 mg of ginseng extract (standardized for 4% ginsenosides) for 12 weeks reported greater improvements in quality of life measured with a questionnaire compared with a group taking only MVM.³⁷ The same MVM-ginseng combination was tested in a double-blind study of night-shift healthcare workers.³⁸ Compared with a placebo group, the group receiving the MVM-ginseng combination improved on one out of four measures of mental performance, one out of three measures of mood (increased calmness, but no change in alertness or contentment), and a measure of reported fatigue. However, in another double-blind study, healthy adults given 200 or 400 mg per day of a standardized extract of Asian ginseng (equivalent to 1,000 or 2,000 mg of ginseng root) showed no significant improvement in any of several measures of psychological well-being after two months.³⁹

A double-blind trial found that Asian ginseng (200 mg per day of standardized extract) helped alleviate psychological symptoms of menopause, such as depression and anxiety, but did not decrease physical symptoms, such as hot flashes or sexual dysfunction, in postmenopausal women who had not been treated with hormones.⁵⁰ In another double-blind trial, supplementation with 3 grams per day of red ginseng (heated Asian ginseng) for 12 weeks significantly improved menopausal hot flashes, compared with a placebo.⁵¹

A double-blind trial found that Asian ginseng (200 mg per day of standardized extract) helped alleviate psychological symptoms of menopause, such as depression and anxiety, but did not decrease physical symptoms, such as hot flashes or sexual dysfunction, in postmenopausal women who had not been treated with hormones.⁵² In another double-blind trial, supplementation with 3 grams per day of red ginseng (heated Asian ginseng) for 12 weeks significantly improved menopausal hot flashes, compared with a placebo.⁵³

Adaptogenic herbs such as Asian ginseng and eleuthero may also be useful for CFS patients—the herbs not only have an immunomodulating effect but also help support the normal function of the hypothalamic-pituitary-adrenal axis, the hormonal stress system of the body.⁵⁵ These herbs are useful follow-ups to the six to eight weeks of taking licorice root and may be used for long-term support of adrenal function in people with CFS. However, no controlled research has investigated the effect of adaptogenic herbs on CFS.