Viagra's secret active ingredient revealed

Washington DC: While most of us turn to dietary supplements to improve our health, people rarely know what 'undisclosed' ingredients they contain, and now scientists have tried to bring them to light.

To protect consumers from taking something without their knowledge, scientists have developed a technique to determine what secret ingredients could be lurking in these supplements.

The approach helped them find the active Viagra ingredient and other synthetic designer compounds in various products.

Regulators have over the past several years detected prohibited substances in some of these products that aren't included on the labels. The drug sibutramine is one of these substances. It was once approved for weight loss but was withdrawn after concerns arose that the medication could increase the risk of heart attacks. To catch supplements spiked with sibutramine and other undeclared substances, Zhiqiang Huang, Bin Guo and colleagues came up with a strategy.

Using an advanced liquid chromatography-mass spectrometry screening procedure, the researchers tested more than 100 syrups, capsules and other types of supplements purchased in markets in China and online. The products' labels claimed benefits from blood pressure reduction to enhanced sexual performance. Their approach successfully detected a wide range of targeted adulterants-including sibutramine and sildenafil, the active ingredient in Viagra-and other unexpected drug compounds.

The report is published in ACS' Journal of Agricultural and Food Chemistry.