by Kerry Bone, BSc (Hons), Dip. Phyto, FNIMH, FNHAA, MCPP

There is actually a long tradition for the use of male tonics in Western herbal medicine. These were typically employed as treatments for impotence; the understanding was that they needed to be consumed for weeks or months for a substantial effect.

With the widespread acceptance of the concept that male sexual performance could be pharmacologically enhanced, a flood of herbal products was released onto the market. It is most likely that these claimed herbal alternatives to Viagra will in general deliver only modest effects at best. But on the other hand, there are a few herbs that do enjoy a credible basis as male tonics, either from a traditional or clinical perspective, or both. Three of these are briefly reviewed below.

Chinese herbal medicine has a rich tradition of male tonics. One that has captured the imagination of clever marketing companies is Epimedium sagittatum, which enjoys the common name Horny Goat Weed. Despite its descriptive name, there are no clinical trials which support the use of this herb for erectile dysfunction, so any claims for its efficacy need to rely on traditional considerations. Interestingly, traditional dictates advise against the long-term use of this herb,¹ something which has been largely ignored by marketing companies.

In contrast, ginseng (Panax ginseng), a well-known male tonic from the Chinese tradition, has been the subject of two controlled clinical trials. The most recently published study, conducted in Korea, investigated the efficacy of Korean red ginseng for erectile dysfunction using a double-blind, placebo-controlled, crossover design.² A total of 45 patients with clinically diagnosed erectile dysfunction received either ginseng root or placebo for eight weeks, followed by a two-week washout period after which each patient received the opposite treatment. The ginseng dose was 2.7 grams per day. The mean International Index of Erectile Function scores were significantly higher in patients treated with ginseng than in those who received the placebo (p<0.01). Objective measurements also confirmed the superiority of ginseng over placebo.

In the second clinical trial, also conducted in Korea, the effect of red ginseng root on impotence was compared to placebo and the drug trazodone.³ A total of 90 patients were closely followed, with 30 patients in each group. The overall therapeutic efficacy on erectile dysfunction as evaluated by the patient 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 ginseng dose used was 1.8 grams of extract per day.

Another popular "herbal Viagra" is the leaf of Tribulus (Tribulus terrestris). Various parts of this ubiquitous weed are used as medicines by different cultures throughout the world. But it is the use of the leaf in Eastern Europe for fertility problems in men and women and to enhance male sexual performance that has captured the imagination. There is some credible evidence from animal and human studies to support these uses. In the case of erectile dysfunction and libido, oral doses of Tribulus leaf extract for 20 days produced a stimulating effect on the sexual function of male rats.⁴ It showed considerable stimulating action on spermatogenesis and increased the density of Sertoli cells in rats. In the treated animals, the spermatozoa were more tenacious and more viable, suggesting improved fertility. Libido was improved as evidenced by accelerated and emphasized sexual activity.

Tribulus leaf extract (250 mg per day) administered for 40 days to male lambs and rams increased plasma testosterone concentrations compared to controls. It also accelerated sexual development, activated spermatogenesis and stimulated seminiferous tubule growth in the immature sheep.⁵ Oral administration of Tribulus leaf extract raised testosterone levels and normalized the sexual activity of rams with sexual impotence. Semen production improved and no morphologic changes in the structure of either testes or epididymides were observed during the treatment period.⁶ In boars with established and prolonged sexual impotence, oral administration at 70 mg/kg per day for 10 days restored libido and sexual reflexes in 71% of the animals with absolute absence of libido. Another five animals with poor libido all demonstrated improvement.⁷

Of 14 patients with reduced libido, 12 showed considerable improvement after 30 days of using Tribulus leaf extract (1,500 mg/day) and one patient was slightly improved after 60 days of treatment. Libido was improved in 27 of 36 patients with chronic prostatitis, but patients with chronic prostatitis of five or more years' duration demonstrated no improvement. In another trial, libido was incidentally improved in patients with hypotrophy of the testes and idiopathic oligospermia.⁸

Unfortunately, many of the Tribulus products on the market do not reflect the same doses or phytochemical profile as the extract studied in Eastern Europe. This is often due to the fact that the Tribulus plant part used in these products is not the leaf. It is unlikely that such Tribulus products will deliver anything other than a placebo effect.