When most people talk about counterfeit drugs, they think of pills that contain inactive, useless preparations at best, or harmful toxic substances at worst. But in Korea, more often than not fake erectile dysfunction drugs are laced with too much active ingredient, researchers reported this week at the American Urological Association annual meeting in San Francisco.

The small study examined 19 copies of Viagra and Cialis purchased at adult sex shops or online in South Korea. Only one pill had the correct dose of the active ingredient, phosphodiesterase type 5 (PDE5) inhibitor. In contrast, 11 pills contained too much drug — often in the form of unapproved analogues of the active ingredient — and seven pills had no active ingredient at all. One pill even contained 2.4 times the normal dose of the drug, SecuringPharma reports.

“Counterfeit PDE5 inhibitors could not be expected [to provide] consistent efficacy by lack of proper active ingredients and could be administered as overdose, which might induce serious side effects,” the researchers concluded in their conference abstract.

To read more about fake and substandard drugs, check out our news focus from the April issue of Nature Medicine.

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