Korean Ginseng and Erectile Dysfunction
A Review of Recent Research
By Kerry Bone, BSc (hons.), Dip. Phyto
Recent clinical trials provide good evidence for the use of Korean red ginseng (Panax ginseng) for erectile dysfunction.In the most recent study, a total of 60 patients with mild to moderate erectile dysfunction were recruited for a double-blind, randomized, placebo-controlled trial conducted in Brazil.1 Patients received either 3 g per day of Korean red ginseng root or a matched placebo for 12 weeks. The five-item version of the International Index of Erectile Function (IIEF-5) was used to assess patients at the beginning and end of the trial. The average patient’s age was 52.6 years (ranging from 26 to 70 years) in the Korean ginseng group and 54.3 years (ranging from 34 to 67 years) in the placebo group. Other health problems included hypertension in nine patients (30%) in the ginseng group and 13 patients (43.3%) in the placebo group, and diabetes in four patients (13.3%) in the ginseng group and six patients (20%) receiving placebo.
By the end of the trial, IIEF-5 scores were significantly higher in the group receiving the herbal treatment compared to baseline (p <0.0001). In contrast, there was no change in the placebo group. In addition, 20 patients (66%) receiving Korean ginseng reported improved erection, compared to none in the placebo group. Levels of serum testosterone, prolactin and cholesterol were not altered significantly by the herbal treatment.
This is the fourth controlled clinical trial demonstrating the efficacy of ginseng in the management of erectile dysfunction. All three previous studies were undertaken in Korea. The first study, published in 1995, compared the effect of red ginseng on impotence against a placebo and the drug trazodone.2 A total of 90 patients were divided equally into three groups. The overall therapeutic efficacy on erectile dysfunction as evaluated by patients was 60% for the ginseng group and 30% for the placebo- and trazodone-treated groups (p <0.05). In particular, ginseng significantly improved libido. The dose used was 1.8 g of extract per day.
The effect of Korean red ginseng on sexual dysfunction and serum lipid profile also was investigated in a controlled study involving 35 elderly men with psychogenic impotence. Treatment was 2.7 g or 1.8 g of ginseng root or placebo for two months. The overall therapeutic effect on erectile function was 67% for ginseng versus 28% for placebo (p < 0.05), and results tended to be better in the higher-dose ginseng group. HDL cholesterol was significantly elevated by ginseng (p <0.05), but there was no other effect on serum lipids.3
In the third Korean study, published in 2002, a total of 45 patients with clinically diagnosed erectile dysfunction were enrolled in a double-blind, placebo-controlled crossover trial (eight weeks of treatment, two weeks of washout and another eight weeks of treatment). The effects of Korean red ginseng root (900 mg, three times daily) and a placebo were compared. Mean IIEF scores were significantly higher for patients taking Korean red ginseng than for those who received the placebo (p < 0.01). Scores on questions three (penetration) and four (maintenance) also were significantly higher in the ginseng group (p < 0.01). In response to the overall efficacy question, 60% of the patients answered that Korean red ginseng improved erection (p < 0.01). Among other variables, penile tip rigidity, assessed using a specialized device, showed significant improvement for ginseng against placebo.4 No changes in serum testosterone were observed.
The range of Korean red ginseng root doses prescribed in the studies was relatively high, varying from 1.8 g to 3 g per day. Also, one trial used 1.8 g of an undefined concentrated extract. These trial data suggest a dose of at least 5 mL per day of a 1:2 Korean red ginseng extract (equivalent to 2.5 g of dried root) is needed for clinical results in erectile dysfunction. An equivalent dose can be used in tablet or capsule form.
One of the concerns about using such relatively high doses of Korean red ginseng in erectile dysfunction is that patients suffering from this disorder often have high blood pressure. The general thinking is that Korean ginseng is contraindicated in hypertension. However, clinical studies (including the Brazilian one mentioned above) do not support such a broad contraindication for this valuable herb.
One Korean study evaluated changes in blood pressure after eight weeks of treatment with red ginseng root (Panax ginseng, 4.5 g/day) using 24-hour blood pressure monitoring.5 Placebo was administered for four weeks followed by red ginseng, which implies the study was unblinded from the perspective of the clinician (in other words, it was a single-blind study). In 26 patients with essential hypertension, average systolic blood pressure decreased significantly (p=0.03), while diastolic pressure only showed a tendency to decline (p=0.17). In eight patients with “white coat” hypertension, no significant blood pressure change was observed, which might be expected given the low number of patients. The authors suggested red ginseng might be considered a relatively safe treatment in conjunction with antihypertensive drugs. Side effects were considered trivial and temporary.
The results of this trial suggest Korean ginseng actually might be relevant in the treatment of hypertension. However, a careful analysis of the data shows the therapeutic benefit is mild and only has minor clinical significance. Systolic blood pressure during treatment dropped only an average of 5.7 mmHg and diastolic pressure fell by only 3.5 mmHg (which is not considered significant). Several patients already were taking conventional medication for high blood pressure (calcium channel blockers and beta blockers), so perhaps the change might have been more marked in unmedicated patients.
What is probably more remarkable about this study is that ginseng did not increase blood pressure. Since the publication by Siegel and the coining of the term ginseng abuse syndrome (GAS), a risk of hypertension was considered a feature of chronic and high ginseng intake.6 Admittedly, Siegel did not differentiate between ginseng and Siberian ginseng (Eleutherococcus senticosus) in his paper, but in a later publication he provided extra details of his findings.7 In the 22 people for whom hypertension developed (among the 133 exhibiting GAS), all had substantial elevations of both systolic and diastolic blood pressure. This included 20 men, 21 to 35 years of age, with normal blood pressure at the start of the study. Eight of these participants were using Eleutherococcus and 14 were taking Panax ginseng. The hypertensive group also included two women using Panax ginseng. No information was provided about any possible adulteration of the herbs used.
Despite these case reports, clinical trials do not support this contraindication. Any hypertensive response to ginseng is probably idiosyncratic and the risk needs to be assessed on a case-by-case basis. This is well-illustrated by an earlier clinical trial that found intake of red ginseng (3 g to 6 g/day) for an average of 10 months yielded the following results:
Hence, while there is a strong tendency for red ginseng to not influence or normalize blood pressure, it will have a contrary effect in a very small percentage of patients. This is not sufficient grounds for a blanket contraindication and suggests Korean red ginseng can indeed be recommended to patients with both hypertension and erectile dysfunction.
About the Author: Kerry Bone is a practicing herbalist; co-founder and head of research and development at MediHerb; and principal of the Australian College of Phytotherapy. He also is the author of several books, including Principles and Practice of Phytotherapy and The Essential Guide to Herbal Safety.
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All Rights Reserved, Naturopathy Digest, 2011.
Date Last Modified - Friday, 17-Oct-2008 12:11:17 PDT