Reviewed: Jang D-J, Lee MS, Shin B-C, Lee Y-C, Ernst E. Red ginseng for treating erectile dysfunction: a systematic review. Br J Clin Pharmacol. October 2008;66(4):444-450.
Erectile dysfunction (ED) affects 30-50% of men over the age of 40. Current medical interventions for the management of ED include drugs, intrapenile therapies, and penile prosthetic implants. Korean red ginseng (Panax ginseng, Araliaceae) is the steamed and dried roots of plants that are harvested 6 years after planting. One of the popular traditional uses of red ginseng is the enhancement of sexual function. Few clinical trials have evaluated the effect of red ginseng on ED, and recent reviews of ED therapies did not include studies published in languages other than English. The purpose of this systematic review was to critically evaluate the evidence from all randomized controlled trials (RCTs) of red ginseng in men with ED.
Researchers at the Korea Institute of Oriental Medicine searched electronic databases from their inception until January 2008. The databases included MEDLINE, AMED (Allied and Complementary Medicine Database), British Nursing Index, CINAHL (Cumulative Index to Nursing and Allied Health Literature), EMBASE (Excerpta Medica Database), PsycInfo, The Cochrane Library, 6 Korean medical databases, 4 Chinese medical databases, and 3 Japanese medical databases. The researchers also manually searched relevant journals and checked the references of all articles identified in the search. The analysis included all articles that reported on an RCT in which human subjects with any type of ED were treated with any type of red ginseng, regardless of language of publication. Three independent reviewers read, extracted, and rated each article.
The researchers identified 28 potentially relevant trials, and 7 of these trials met the criteria for inclusion in the analysis.1-7 A total of 363 men, ranging in age from 24 to 70 years, were studied in these 7 trials. The duration of treatment with red ginseng ranged from 4 to 12 weeks. The doses of red ginseng ranged from a daily total of 1800 mg to 3000 mg. (Presumably, this dosage range refers to the dried root powder as extracts would probably be expressed in lower daily doses. The trade names of any commercial ginseng products that may have been used in the RCTS were not given.) Outcome measures included scores on the International Index of Erectile Function, the Watts sexual function questionnaire, global efficacy questions, and study-specific structured interview questionnaires related to ED.
Six of the trials reported an improvement in erectile function in subjects taking red ginseng compared to subjects taking placebo. A meta-analysis of data from the 7 trials suggests that red ginseng is superior to placebo in improving erectile function (P < 0.0001). The methodological quality of the trials was variable, ranging from scores of 1 to 5 on the Jadad scale. The majority of the articles failed to report the method of randomization, the method of double-blinding, and details about subject withdrawals and drop-outs. Other shortcomings included failure to report a power calculation for statistical analysis and failure to report approval of the study by a research ethics board. (The use of red ginseng in Korea particularly, as well as in China, is widespread, even ubiquitous; it is sold and consumed as a food, similar to coffee and tea in Western countries; thus the usual requirement to have an institutional review board approve the design of a proposed RCT may not have been seen as necessary.)
The authors explain that this is the first systematic review and meta-analysis of RCTs of the effectiveness of Korean red ginseng in men with ED. They conclude that these trials provide evidence suggesting such effectiveness. However, the number of trials that could be included in the analysis, the total sample size (363 men), and the typical methodological quality of the studies were too low to allow firm conclusions to be drawn. The authors recommend that additional studies with better methodological quality are needed to establish whether or not Korean red ginseng has a place in the treatment of ED.
—Heather S. Oliff, PhD
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