An erectile dysfunction supplement causes abnormalities that can be fatal in some people.

The makers of Enzyte, a product sold online in the US, claim it gives men stronger, firmer and longer-lasting erections. However, research just carried out indicates that the supplement carries risks. Enzyte was found to decreased men’s heartbeats in a ‘worrying’ way, researchers said. Doctors from the Loyola University Chicago now say that patients should avoid the supplement under more information is acquired.

Dr Brian McBride from the university said: “Enzyte appears to have some of the properties of some of the most powerful heart rhythm controlling medications that we give by prescription.”

Enzyte’s ingredients include the herb ginseng, and Viagra substitute ‘horny goat weed’. Horny goat weed is a Chinese plant that has aphrodisiac properties. It contains the same basic active ingredient as Viagra.

Men taking Enzyte are likely to be older, and researchers say this is particularly concerning. Erectile dysfunction is most common in men above 40. Half of men above the age of 40 will experience erectile dysfunction.

Because Enzyte is a dietary supplement, its manufacturers do not need to prove its efficiency. Under American law, supplements are considered safe “unless proven otherwise.” Researchers note that two drugs cisapride and terfenadine, both had similar effects on heart rate, and both were promptly banned by the Food and Drug Administration. Both drugs were found responsible for causing sudden death in users. Dr McBride says the FDA should look into pulling Enzyte from the market before the same thing occurs.

The major FDA-approved drugs available to treat impotence are Viagra, Cialis and Levitra. All three of these drugs have been clinically proven to help men with erection problems. However, the FDA recommends that men with heart conditions should speak to their doctor before thinking about taking the drug. Studies have shown that Viagra can worsen pre-existing heart conditions, as the drug raises heart rate.