Erectile dysfunction supplements being sold online have little to no science to prove they work, experts have warned.
A study of 21 ingredients used in six of Amazon’s most highly rated erection supplements in the US found most had never even been tested in a study.
Only four ingredients had ever been proven to help and, while each pill contained at least one of those four, they also contained many other unproven ones.
The research also found a vast majority of positive reviews may not have been from genuine customers.
Scientists said people should be wary of being swayed by positive reviews or marketing and may be better off with medical options like Viagra.
Six erectile dysfunction supplements for sale on Amazon in the US were found to contain a total of 17 active ingredients for which experts couldn’t find any scientific evidence to prove they would help a man with erection difficulties
The research by the Baylor College of Medicine in Texas looked at six of the most popular supplements on Amazon in September 2018.
The products were Korean Panax Ginseng (by NutraChamps), Leyzene with Royal Jelly (Natural Subsistence), Horny Goat Weed Extract (Zhou Nutrition), Boost Elite (Zhou Nutrition), Extra Strength L Arginine (Havasu Nutrition), and IncrediBULL (eSupplements).
They contained four ingredients which studies suggest could actually improve the strength and frequency of a man’s erections were ginseng, l-arginine, tribulus terrestris and maca root.
But the supplements also contained 17 other ‘active’ ingredients which science has never proved could improve erections, the research showed.
These included tongkat ali, horny goat weed, muira puama, capsicum annuum, zinc, epimedium, saw palmetto berry, fenugreek seed and yohimbe bark.
Diindolylmethane, AAKG, piperine, gluconolactone, L-citrulline malate, polypodium vulgare, rehmania root and royal jelly all also had no science to suggest they work.
Researchers trawled a database of past scientific studies of any of these ingredients’ effects on erectile dysfunction, taking in 413 studies in total – 69 on humans.
WHICH INGREDIENTS HAVE ANY SCIENCE TO BACK THEM UP?
Research in the Journal of Sexual Medicine revealed many ingredients contained in supplements which claim to improve men’s erections have no scientific evidence to prove they work.
Here is a list of each ingredient and the number of scientific studies which found they had a beneficial effect in men with erectile dysfunction:
- Ginseng (5)
- L-arginine (4)
- Tongkat ali (0)
- Horny goat weed (0)
- Tribulus terrestris (2)
- Maca root (1)
- Muira puama (0)
- Capsicum annuum (0)
- Zinc (0)
- Epimedium (0)
- Saw palmetto berry (0)
- Fenugreek seed (0)
- Yohimbe bark (0)
- Diindolylmethane (0)
- AAKG (0)
- Piperine (0)
- Gluconolactone (0)
- L-citrulline malate (0)
- Polypodium vulgare (0)
- Rehmania root (0)
- Royal jelly (0)
Source: Journal of Sexual Medicine
The scientists, led by Dr Alexander Pastuszak, wrote in their report: ‘Physicians must be aware of the ingredients in these supplements to better counsel patients about the efficacy of these supplements.
‘Although consumer reviews hosted on [erectile dysfunction] online product pages prominently tout product efficacy, primary evidence supporting positive effects of these products on ED symptoms is lacking.’
Erectile dysfunction is a common condition which leaves men struggling to achieve or maintain an erection for sex.
The condition gets increasingly common as men get older, and mild or occasional problems may affect more than half of men over the age of 50.
Medically approved drugs which help men struggling to get an erection include Viagra, Cialis, Levitra and Spedra – Viagra is now available without a prescription.
The research also found almost half of reviews for the erection supplements were ‘untrustworthy’.
And when the untrustworthy reviews were filtered out, the number claiming the products worked was dramatically reduced.
Some 90 percent of the comments claiming an increase in sexual satisfaction were filtered out for being suspicious, the research said.
As well as this were 83 percent of reviews reporting better erection maintenance and 77 percent which claimed they had better erection strength.
At the end of their paper the scientists suggested people should be ‘cautious’ about using supplements unless better human data was published.
This was ‘particularly in light of the availability of highly effective FDA-approved drugs and increasingly affordable therapeutic options,’ they added.
The research was published in the Journal of Sexual Medicine.
MailOnline has contacted Amazon for comment.
WHAT CAUSES IMPOTENCE?
Erectile dysfunction, also known as impotence, is when a man is unable to get or maintain an erection.
It is more common in the over-40s but affects men of all ages.
Failure to stay erect is usually due to tiredness, stress, anxiety or alcohol, and is not a cause for concern.
However, it can be a sign of an underlying medical condition such as high blood pressure or cholesterol, side effects of medication, or hormonal issues.
Lifestyle factors than can affect the condition include obesity, smoking, cycling too much, drinking too much, and stress.