(CNN) -- The makers of an over-the-counter male sexual supplement are recalling the product after government tests showed some unlisted ingredients "pose a threat to consumers," the company says.
Tests conducted by the Food and Drug Administration found that the supplement X-Rock contained sildenafil -- an approved drug to treat erectile dysfunction -- and related substance, hydroxythiohomosildenafil, the product's manufacturer said in a statement annoucing the voluntary recall. The announcement from the product's manufacturer, X-Rock Industries, was posted on the FDA's website.
"These undeclared active ingredients pose a threat to consumers because sildenafil and hydroxythiohomosildenafil may interact with nitrates found in some prescription drugs (such as nitroglycerin) and lower blood pressure to dangerous levels," X-Rock Industries said.
Erectile dysfunction is more common in men with diabetes, high blood pressure, high cholesterol and heart disease, who are generally more likely to take nitrates, the statement noted. But the company "has not received any reports of adverse events related to this recall," it said.
The voluntary recall "is being conducted with the knowledge of the U.S. Food and Drug Administration," X-Rock said.
The product's website, XRockme.com, describes the U.S.-manufactured supplement as "totally organic." It contains "many potent, proprietary natural ingredients -- absolutely no chemicals or steroids," the website states.
In addition to Internet sales, the company says X-Rock is sold at retail locations in Nevada, California, Florida, New York, New Jersey, South Carolina "and a few more states." People can return the product to where it was purchased or call 877-976-2563 between 9 a.m. to 9 p.m. ET Monday through Saturday for more information on getting a refund, the company said in its release.