Hundreds of dietary supplements contain potentially 'dangerous' ingredients, finds study

More than one unapproved pharmaceutical ingredient was found in 25 per cent supplements

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Hundreds of dietary supplements sold over the counter in the US contain unapproved and potentially dangerous drugs, a new study has found.

Researchers from the California Department of Public Health found that, from 2007 to 2016, 776 products marketed as dietary supplements contained hidden ingredients that are unsafe or unstudied.

Among them were dapoxetine, an antidepressant that is not approved in the US, and sibutramine, an appetite suppressant that was banned from the US market in 2010 because of cardiovascular risks.

Despite these findings, more than half the time, the Food and Drug Administration (FDA) did not enforce recalls of supplements that knowingly contained potentially dangerous ingredients.

The team based their research on an analysis of an FDA database that identifies “tainted” supplements; meaning that the product contains ingredients that are not listed on the label.

The study, published in JAMA Network Open, revealed that more than one unapproved pharmaceutical ingredient was found in 25 per cent of those supplements.

Most of which, about 45 per cent, were marketed for sexual enhancement, weight loss (41 per cent) and muscle-building (12 per cent).

Among the drugs found in sexual enhancement products were sildenafil, tadalafil and vardenafil, all active ingredients in prescription medications intended for erectile dysfunction, which, when overused, can potentially cause serious damage to the blood vessels.

Similarly, the most common pharmaceutical ingredient detected in the weight loss products was sibutramine, which was removed from the US market in 2010 due to cardiovascular risks.

Almost all the muscle building supplements, 82 out of 92 products, contained synthetic steroids or steroid-like ingredients, which, when abused, can lead to mental health problems, kidney and heart problems, and liver damage.

“These products have the potential to cause severe adverse health effects owing to accidental misuse, overuse, or interaction with other medications, underlying health conditions, or other drugs within the same dietary supplement,“ wrote the authors, led by Madhur Kumar of the California Department of Public Health Food and Drug branch.

“As the dietary supplement industry continues to grow in the United States, it is essential to further address this significant public health issue.”

So, what did the FDA do about these supplements?

According the study, very little. Of the 776 supplements that were identified to contain hidden ingredients, the FDA requested voluntary recall of less than half (46.4 per cent), and of that amount, only 334 recalls actually happened.

“The agency's failure to aggressively use all available tools to remove pharmaceutically adulterated supplements from commerce leaves consumers' health at risk,” Dr. Pieter Cohen, a general internist at Cambridge Health Alliance in Somerville, Massachusetts, wrote in a commentary accompanying the study.

In light of the findings, the authors highly recommend that anyone wanting to take a supplement liaise with their physician beforehand.