The U.S. Food and Drug Administration (FDA issuing a warning Thursday said Stiff Nights, a product marketed as a dietary supplement for sexual enhancement, an labelled as all-natural, contains an illegal ingredient that dangerously lowers blood pressure.

Many products marketed as dietary supplements for sexual enhancement over the past several years, have been found to contain undeclared active ingredients from FDA-approved drugs, analogs of approved drugs, including other compounds failing to qualify as ‘dietary ingredients’.

Multiple alerts have been issued about these contaminated dietary supplements, and health care professionals, including consumers made aware of this problem and the health hazard it presents. Sexual enhancement products claiming they work as well as prescription products contain contaminants, exposing consumers to risk, injury, even death.

A consumer complaint leading to FDA examining Stiff Nights, found the product to contain sulfoaildenafil, a chemical similar to sildenafil, which is an active ingredient in Viagra. Any interaction between Sulfoaildenafil and prescription drugs like nitrates or nitroglycerin, causes dangerously low blood pressure.

Sulfoaildenafil sold in bottles containing 6, 12 or 30-red capsules, or blister packs of one or two capsules, is distributed on Internet sites and retail stores by Impulsaria LLC of Grand Rapids, Mich. A bottle of 12 Stiff Nights capsules were being offered on Amazon for around $27 dollars, while another website www.mystiffnights.com stated the product was made with ‘only the finest herbs and greens’.

The product’s labelling as an ‘all natural dietary supplement’ may lead consumers to believe it to be harmless, with no risk to health, but in fact it is being sold illegally and can cause serious complications.

FDA recommends any adverse events from sexual enhancement products must be reported to a health care professional, with both consumers and health care professionals reporting them to FDA’s MedWatch programme at 800-FDA-1088, or online at www.fda.gov/medwatch/report.htm.