London, Aug 6 (IANS): Be warned! New research has revealed that you might be inadvertently taking an active ingredient of Viagra in your dietary supplement that claims to improve your well-being.

Many dietary supplements contain undeclared substances. Their labels list herbs or other natural ingredients that consumers assume are safe to take.

Now Chinese researchers have developed a new method to determine what secret ingredients could be lurking in these supplements.

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

“Our approach successfully detected a wide range of targeted adulterants - including sibutramine and sildenafil, the active ingredient in Viagra - and other unexpected drug compounds,” said researcher Zhiqiang Huang.

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 It was once approved for weight loss but was withdrawn after concerns arose that the medication could increase the risk of heart attacks.

Using an advanced liquid chromatography-mass spectrometry screening procedure, the researchers from Hunan Normal University, China, 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.

The findings were published in the Journal of Agricultural & Food Chemistry.