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It’s never been easy for me to take a product called ‘Horny Goat Weed’ seriously. When I first heard the name at least a couple decades ago, I started laughing; thought it was a joke. Then I figured it was a gimmick. What are we supposed to assume? Is it that goats get horny after eating this stuff? And is the visual I get from that meant to help me think this “weed” will make ME horny?

Well, apparently quite a few Amazon reviewers think it makes THEM horny. Such anecdotal feedback can be seen in a couple of product review sections of powdered forms of nothing but the pure extract. With only scattered exceptions, one guy after another claims HGW worked wonders on his libido.

So what’s the deal with Horny Goat Weed and testosterone? Does this Asian herb help boost it?

It’s a good question given the product might only be a nitric oxide enhancer that improves erectile function. This is where ambiguity about the herb’s effect really surfaces. After all, a nice boost in nitric oxide can improve erectile performance. This can lead to a slight indirect boost in testosterone via the psychological route.

But is HGW raising testosterone through a direct route? If so, that would make the stuff much more interesting. Let’s face it, anything less would reveal the herb’s effect subpar in terms of strength and muscle building enhancement. It might even expose it as ‘impotent’ for long-term libido enhancement.

So with very few studies to draw from, let’s look at the ‘Horny Goat Weed and testosterone’ evidence.

 

‘Horny Goat Weed and Testosterone’: Animal study

The timeworn rodent study often cited in the question of whether Horny Goat Weed boosts testosterone was done in 2006 at Shantou University in China. Researchers divided 48 rats (15 months old) into four groups of 12 rats each. One group was a ‘control’ that received no treatment (C). The three remaining groups were given cyclophosphamide for five days in order to intentionally damage their testes.

These three remaining experimental groups were labeled M, T, and ICA respectively. The ‘M’ group received no treatment for the toxic exposure to cyclophosphamide. The ‘T’ group received injections of 5 mg testosterone/kg of bodyweight for a week after the five days of toxin exposure. The ‘ICA’ group was given 200 mg/kg of bodyweight of icariin for a week following exposure to the toxin.

Icariin is the flavonoid in HGW that’s believed to improve erectile function by acting as a natural PDE-5 inhibitor (‘natural Viagra’).

But in this rat study, it appeared to significantly restore the reproductive systems and testosterone levels of rats in the ICA group. That group (receiving icariin) ended up with testosterone 263% higher than that of the control group.

 

 

Obviously, the M group ended with damaged goods and no follow-up treatment. Since their testosterone ended way below that of the control group, the ICA group ended with over 1,200% higher testosterone than M’s.

The T group got synthetic testosterone as their follow-up treatment. With that, their testosterone wound up off the charts compared to the control group. But interestingly, it ended up only about 220% higher than the ICA group.

It’s strange that the researchers named this experiment ‘The testosterone mimetic properties of icariin’. Seems like a misnomer to me. Shouldn’t it be something like ‘The testosterone restorative properties of icariin?’ If anything in the study reflects “mimetic” properties, it’s the synthetic testosterone given to the T group.

Obviously, not my call.

 

‘Horny Goat Weed and Testosterone’: An Extrapolation

Horny Goat Weed is a colloquial term for a flowering plant called epimedium. It is endemic to China but is also found in lesser quantities in other Asian countries and the eastern Mediterranean. Known in China as Yin Yang Huo, it’s long been used there as a folk medicine and aphrodisiac.

The reason discussions of horny goat weed are met exclusively with citing of rodent studies and anecdotal evidence is the sheer lack of human study done on the herb. Thus far, nobody’s appeared to want to fund one. There have been test tube studies revealing its PDE-5 inhibiting effect. But nothing has been done with human experiments to discover whether it would benefit anyone’s hormones other than those of an abused rat.

However, in determining whether it will help boost long-term testosterone in humans, we might extrapolate from an animal study that measured the effect of icariin on a different organ – the brain. In this study, researchers added high quantities of aluminum to the drinking water of rats for eight months. This was done to discover what effect the metal would have on the animal’s special learning and memory, and whether icariin could ameliorate such effect.

Lo-and-behold, the high levels of aluminum definitely produced spatial learning and memory deficits in the rats. And icariin treatment (60 and 100 mg/kg of bodyweight) dose-dependently protected an experimental group of rats against these aluminum-induced spatial learning and memory deficits.

“So how might that provide clues about boosting testosterone”, you ask?

In observing how icariin protected the animal’s brains from aluminum, the researchers in this study noticed a decrease of both malondialdehyde and lipid peroxidation in the hippocampus areas of the icariin treated rats. They also noticed a significant increase in super-oxide dismutase activity. This is all evidence that the protection afforded by icariin was due at least in part to anti-oxidant defense against lipid peroxidation caused by the heavy metal.

A number of studies show that it’s lipid peroxidation and a buildup of malondialdehyde that cumulatively hobble the testes from maximum testosterone production with age. Could the icariin in horny goat weed create a defense against this oxidative damage?

This is a good question that could actually be asked about a number of eastern herbs thought to be aphrodisiacs/libido boosters.

 

‘Horny Goat Weed and Testosterone’: Mind Route

As a PDE-5 inhibitor, if horny goat weed can significantly improve nitric oxide and erectile function, then this is a route by which it could increase testosterone slightly, albeit through the   psychological route. This was demonstrated with the purported nitric oxide booster Prelox®. Test subjects receiving it wound up with a 19% boost in ‘total-T’ that researchers attributed to an indirect effect of better sexual performance. Bottom line: The subjects had sex more often due to better erectile performance. Increased sexual activity can result in a slight testosterone boost.

Obviously, this might entirely explain the positive anecdotal feedback of HGW in review sections like that of Amazon’s. The feedback is most often ambiguous with a blur between better sexual performance and higher libido. These are not the same and don’t always coincide with one another.

Other anecdotal feedback on HGW often relates to ‘gym performance.’ But this doesn’t necessarily mean increased muscle growth, which is a better indication of a significant testosterone boost. When a user of HGW writes “It give me more energy in the gym”, I’m reading something entirely explainable by the endothelial cell relaxing factor of a PDE-5 inhibitor that can result in better circulation and more oxygen uptake. It doesn’t say much for the ‘horny goat weed and testosterone’ hypothesis.

 

Horny Goat Weed and Testosterone: Bottom line

Whether HGW actually boosts testosterone probably depends on whether it has a long-term effect on human testicular health. In the rat study mentioned above, it had a significant restorative effect. If a reasonable dosage has a respectable degree of this effect in humans, it could help restore or preserve otherwise declining natural testosterone.

For anyone thinking of trying it, only do so under a physician’s supervision. Especially in its PDE-5 inhibiting role, HGW can interfere with prescription drugs.

 

References

 

  1. Zhang Z., Yang QT. ‘The testosterone mimetic properties of icariin.’ Asian Journal of Andrology (Volume 8, Issue 5, Pages 601–605) Sept. 2006
  1. Luo Y, Nie J, Gong QH, Lu YF, Wu Q, Shi JS. ‘Protective effects of icariin against learning and memory deficits induced by aluminum in rats.’ Clinical and Experimental Pharmacology and Physiology (Volume 34, Issue 8, Pages 792–795) Aug 2007
  1. Hiromitsu Aoki, Junji Nagao, Taro Ueda, Jeffry M. Strong, Frank Schonlau, Song Yu-Jing, Yan Lu, Shigeo Horie. ‘Clinical Assessment of a Supplement of Pycnogenol® and l-arginine in Japanese Patients with Mild to Moderate Erectile Dysfunction’ Phytotherapy Research (Volume 26, Issue 2, Pages 204–207) Feb 2012