Does Horny Goat Weed Really Work?


Horny Goat Weed is one of those herbs whose name evokes lingering curiosity – does it deserve its reputation in the bedroom, or not?

When I thought I’d found one lurking in my rockery, I discovered that despite its renowned use as an aphrodisiac, most of the current research into Horny Goat Weed is exploring its potential to treat osteoporosis, Alzheimer’s and drug-resistant cancers.



Horny goat weed as an aphrodisiac

In traditional Chinese medicine, Horny Goat Weed has been used for over 2000 years to enhance reproductive health in both men and women. It is included in remedies to treat low libido, infertility, impotence, pre-menstrual syndrome and menopause. It is also used as a general tonic to maintain long-term, youthful vigour and good health.

valentn2Any herbal remedy that is consistently used for thousands of years is likely to have more than a placebo action. Pinning this down in the scientific literature isn’t easy, however, as leaves from 15 or more different species of Epimedium are used in traditional Chinese medicine. These are collectively known as Herba Epimedii, or Yin Yang Huo – a name that apparently translates as ‘obscene goat leaves of pulse plants’.

Each Epimedium species contains its own unique blend of over 260 chemicals – including at least 37 different flavonoids. Of those that they all have in common, attention has turned to one called icariin, and its derivatives such as icaritin and a series of icarisides.

Early studies suggested that icariin has a similar effect to drugs such as sildenafil (Viagra) which are prescribed to treat erectile dysfunction. These work by inhibiting an enzyme, phosphodiesterase type-5 (PDE5) which promotes blood vessel dilation during sexual stimulation to achieve and maintain an erection. Even dilute extracts from Horny Goat Weed were found to inhibit PDE5 by 80%.

But Viagra isn’t an aphrodisiac – it requires sexual stimulation to work. So the ability of Horny Goat Weed to inhibit PDE5 would not be expected to produce an aphrodisiac effect, on its own. This action, while beneficial for goats with erectile difficulties, is unlikely to account for apocryphal tales of goats becoming lusty soon after eating Horny Goat Weed leaves. Some other components with hormonal actions must be involved.

The most likely candidates are flavonoids with an oestrogen-like action and a series of unique epimedins, epimedosides and icariososides were recently extracted and identified for the first time. After two millenia of traditional use, 2016 may mark the year when the evidence base for Horny Goat Weed’s aphrodisiac action finally gained some traction.

Currently, however, no-one can explain exactly how Horny Goat Weed works as an aphrodisiac. Its mode of action in treating erectile problems is on a firmer footing, with veterinary studies suggesting it may stimulate erection in aged, diabetic and even castrated animals. Surprisingly, its effects on human male and female sexual function have not yet been evaluated in gold-standard randomised, controlled trials.



Horny goat Weed and Menopause

too_hotAs well as containing unique oestrogenic flavonoids, Horny Goat Weed contains the isoflavones, genistein and daidzein, which are also found in soy. These isoflavones provide a useful oestrogen boost for older women, to reduce hot flushes, and to provide some protection against heart disease and bone loss.

Many women are unable or unwilling to take prescribed hormone replacement therapy to alleviate menopausal symptoms. A randomised controlled trial compared the effects of Horny Goat Weed against placebo in 90 post-menopausal women.

After six months, those taking Herba Epimedii showed significant improvements in total cholesterol and triglyceride levels, and increased blood levels of oestradiol, but no changes in progesterone or testosterone levels. The researchers concluded that Horny Goat Weed has beneficial actions in postmenopausal women and added that, as no serious adverse effects were observed, the extract may be superior to HRT.

Unfortunately, there is no record of whether the women taking the Horny Goat Weed extract were asked if it affected their libido.

Horny goat Weed and Osteoporosis

Horny Goat Weed is a traditional Chinese herbal medicine used to prevent and treat thinning bones.

One of the few human clinical trials to involve Horny Goat Weed tested extracts against placebo in a hundred postmenopausal women whose bone health was monitored for two years.

The women were randomised into two groups, with half taking an Epimedium extract (containing 60 mg Icariin, 15 mg Daidzein and 3 mg Genistein) plus 300mg calcium per day, while the other half took calcium alone.

After 24 months, significant differences were found between the two groups. In those taking low-dose calcium alone, bone mineral density decreased in the femoral neck by 1.8% and in the lumbar spine by 2.4%. In those also taking the Horny Goat Weed, however, bone mineral density increased at the femoral neck by 1.6%, and in the lumbar spine by 1.3%. Blood levels of chemicals associated with bone metabolism suggested that the extracts inhibited bone resorption and rebalanced bone turnover to favour new bone formation.

No changes were seen in blood levels of estradiol (a human oestrogen) nor endometrial thickness, and the researchers concluded that Epimedium-derived phytoestrogen flavonoids exert a beneficial effect on preventing bone loss in late postmenopausal women without detectable adverse effects.

Again, there is no record of whether the women taking the Horny Goat Weed extract in this study noticed any effects on their libido (though I’ve emailed the researchers to ask).

Horny Goat Weed and ALzheimer’s dementia

Icariin may protect against dementia of Alzheimer’s type by inhibiting the build up of abnormal amyloid proteins, blocking the phosphorylation of tau protein, regulating calcium movements and reducing inflammation.



Horny Goat Weed and Cancer

In laboratory studies, icariin has anti-cancer activity against a wide range of human cancer cells, including those derived from stem cells and those which are drug resistant.

Icariin appears to work as a biological response modifier by triggering mechanisms that usually cause abnormal cells to self-destruct (apoptosis), by priming immune defences, by regulating the cell growth cycle, by preventing the ability of tumours to produce their own blood vessels, and by preventing cancer cell spread. Research also suggests that icaritin may be effective against hormone-dependent cancers (eg prostate, breast) that are resistant to hormone treatments, through effects on their hormone receptors.

It’s early days, and has not yet reached the stage of clinical trials, but icariin is under investigation as a potential anti-cancer drug to enhance the effectiveness of chemotherapy regimens.

In conclusion

rockery-plantHorny Goat Weed has survived over 2000 years of use by discerning punters and may well have beneficial effects on libido and erectile function. These haven’t been scientifically quantified but there is a definite spike in interest in both Horny Goat Weed extracts, and in synthetic icariin derivatives – one of which was 80 times more potent in its ability to inhibit the PDE5 enzyme than icariin itself.

Based on anecdote and traditional use, Horny Goat Weed extracts may be worth a go – do share your experience via the comment box below….

Oh, and that rockery plant whose heart-shaped leaves triggered my interest?

Turns out it wasn’t a variegated Epimedium sagittatum after all, but a rather lovely Houttuynia cordata ‘Chameleon’. Almost a shame!

If your libido is flagging, click here to read my feature on Diet And Low Sex Drive

NB Do not take Horny Goat Weed if you are taking any medications or have any long-term health problems except under medical supervision.

 

hgw__gbIn the UK, Simply Supplements combine Horny Goat Weed (2000mg) with Ginkgo biloba (200mg), another herb that promotes blood flow to the peripheries. This product is made to pharmaceutical (GMP) standards.

Check current price and product reviews on Simplysupplements.net

OVERCOMING Low Sex Drive Kindle cover 2

My book, Overcoming Low Sex Drive, explains how your libido is controlled, and the many reasons why it can fail. As well as describing the research behind herbal medicines, vitamins, minerals and other supplements, it provides twelve plans – five for men and seven for women – to help boost a low libido, whatever the underlying cause.

Available from Amazon.co.uk

Buy from Amazon.com

Image credits: KENPEI/wikimedia 


 



About DrSarahBrewer

Dr Sarah Brewer MSc (Nutr Med), MA (Cantab), MB, BChir, RNutr, MBANT qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. After working in general practice, she gained a Master's degree in Nutritional Medicine from the University of Surrey. Sarah is a licensed Medical Doctor, a Registered Nutritionist, a Registered Nutritional Therapist and the award winning author of over 60 popular self-help books. Sarah's other websites are www.MyLowerBloodPressure.com and www.ExpertHealthReviews.com.

Leave a comment or ask me a question ...