"While the FDA does not assess the safety of supplements prior to market, the agency is tasked with identifying and removing adulterated and hazardous supplements from the marketplace", he wrote.
The active ingredients in Viagra, Cialis and Levitra - widely found in the sexual enhancement supplements - can interact with nitrates found in medicine prescribed for diabetes, high blood pressure and high cholesterol and can dangerously lower blood pressure, the researchers said.
Results: Unapproved pharmaceutical ingredients were identified in 776 dietary supplements, majority marketed for sexual enhancement, weight loss or muscle building; 20 percent of the products had more than one unapproved ingredient; and 28 products were named in two or three warnings.
There may be a good reason why that miracle herbal supplement is working so well - it may be getting some help from the big guys - active pharmaceuticals - according to a new analysis of a US Food and Drug Administration database. This study analyzed data from a tainted supplements database maintained by the FDA for trends in adulterated dietary supplements associated with a warning by the FDA. Twenty-eight products were named in two or three warnings more than 6 months apart. As a result of these unapproved ingredients, the FDA issued warnings for these products, which most often came in the form of a voluntary recall to be issued by the supplement manufacturer (46.4%) or a public notification (44.1%).
Though the FDA "has other enforcement tools at its disposal", the new study is consistent with previous research showing "major deficiencies in the FDA's regulation of supplements", wrote Cohen, who was not involved in this study.
The FDA's Dietary Supplement Health and Education Act of 1994 essentially places the burden for evaluating supplement safety, content and labeling primarily on the shoulders of the manufacturers, he said.
Overall, almost 80 percent of all the supplements contained one unapproved drug ingredient, while over 20 percent contained more than one.
But the agency only issued voluntary recalls on 360 products - less than half the number of adulterated products they actually found. But "the shocking finding in the current study is that... over half the [supplement] brands that contain drugs never even were recalled in the first place, ' Cohen told Live Science".
Even after taking action against companies, the FDA sometimes "faces several challenges in deterring fraudulent marketing of these types of products", including relabeling of products to evade detection, Haake wrote. Others may choose them because they are less expensive or because they are readily available at gas stations and convenience stores, Cohen said. She noted that once an adulterated supplement is discovered, "the agency's primary objective is to mitigate any risk posed to public health by informing consumers about any dangers associated with the product and to work to remove it from the market as soon as possible". Every Friday, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. For example, sibutramine can increase blood pressure or heart rate, which could be risky for people with a history of stroke or heart disease.
About 80 percent of the supplements were contaminated by one pharmaceutical that should not have been in the product. But despite their recent popularity, a recent study shows that these supplements may not be what consumers think they are.
'There are actively experimental drugs in supplements that the FDA is aware of but they are not sharing that information with the public, ' says Dr Cohen.
As such, experts are now urging the FDA to take urgent action to have these products removed from the market.