Erectile dysfunction is nothing to laugh about. But what if ED could be helped by an extract from a plant called horny goat weed? Horny goat weed and related herbs have purportedly been treatments for sexual dysfunction for years. Now scientists may be a step closer to discovering how compounds from horny goat weed may work.
My Take?
The ability to get and maintain an erection depends upon blood flowing into the penis and staying there long enough. One way drugs like Viagra work is to inhibit an enzyme called PDE-5, thereby keeping blood flowing to the penis.
WebMD Health News is reporting that researchers, led by Mario Dell’Agli at the University of Milan, found that the main compound in horny goat weed, called icariin, acted the same way that Viagra does.
The research team studied a handful of plants and the compounds in them. They found that out of all the plant compounds, icariin was the most potent of the group.
Scientists tested icariin and other plant compounds in a lab by exposing them to an enzyme that regulates blood flow to the penis. They also chemically modified the icariin and found that its effect in the lab was similar to that of Viagra. 
They write that this “is a promising candidate for further development.” They warn, however, that some plant extracts could actually “interfere with erectile function.” The study is to be published in the Oct. 24 issue of the Journal of Natural Products.
However, these products are NOT regulated in the U.S., therefore, you can never be sure of what you are purchasing.
For example, in January 2006, ConsumerLab.com, an independent testing lab that I trust and recommend, tested products containing epimedium (Horny goat weed). Here’s what they found:

• None of the four products tested for their Horny Goat Weed content passed testing. 
• To pass testing, products were expected to contain no more than 0.5 mcg of lead in a daily serving — the limit set by the State of California for supplements to be sold without a lead warning. 
• Two products exceeded this limit. 
• Products were also expected to contain specific amounts of the compound icariin — a component of Horny Goat Weed. 
• Three products (including one contaminated with lead) fell short of their icariin levels — suggesting that they either contained less ingredient than promised or were made with low quality material. 

The following products failed testing:
• Pinnacle Horny Goat Weed only contained 31% of the amount of icariin claimed per capsule.
• Dymatize® Nutrition Excite™ Male Performance, had 0.95-2.86 mcg lead in its suggested daily dose of one to three capsules per day. It also had only 76% of its claimed amount of icariin.
• Planetary Formulas® Full Spectrum™ Horny Goat Weed, had 2.98 mcg lead in its suggested daily dose of two tablets.
• Source Naturals® Male Response™, only contained 52% of the amount of icariin claimed per tablet.
ED is a condition that affects some 18 million men in the U.S. And, at this point in time, I cannot recommend this product to my patients. Rather, I’m far more comfortable recommending prescription products – not the natural medications – at least for erectile dysfunction.
SOURCES: Dell’Agli, M. Journal of Natural Products, Oct. 24, 2008. News release, American Chemical Society.