Michael Lamb at Arcadia University in Glenside, Pennsylvania, and colleagues presented their work last week at the American Academy of Forensic Sciences meeting in Washington, D.C.
Researchers purchased 10 popular "natural" remedies on the internet and tested them for the presence of sildenafil, the active ingredient in Viagra. They found the compound, or a similar synthetic drug, in seven of the 10 products.
The findings are cause for concern as taking unknown amounts of active prescription ingredients can be dangerous for consumers and so-called "herbal" Viagras have been recalled for that before. If a consumer believes the supplement is natural, it can cause dangerously low blood pressure in some of these unaware men.
Dietary supplements, unlike medications, are not required to be standardized to ensure batch-to-batch consistency. And since the FDA doesn't regulate supplements the same way as drugs, "natural" supplements can make it to market with real drugs in them, only getting recalled once the FDA receive enough complaints.
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