A new study presented this week at the American Heart Association meeting in New Orleans raised fresh concerns about the long-term use of melatonin.

Melatonin—one of the most common over-the-counter sleep aids—was associated with an 89% higher risk of developing heart failure in people who used it for more than one year. Long-term users were also 3.5 times more likely to be hospitalized for heart failure compared with non-users.

For years, melatonin has been considered a safe supplement, used widely by adults and even children. Whether melatonin truly increases the risk of heart failure remains uncertain, and further research is needed. But findings like these raise a larger question: How safe are the supplements we take?

The FDA tightly regulates prescription medications. They must be proven safe, effective, accurately labeled, and free of contaminants. Dietary supplements and most food additives, however, are not regulated in the same way. As a result, it is often unknown whether a supplement contains contaminants such as heavy metals (lead, arsenic), pesticides, or unlisted ingredients—and whether the product actually contains what the label claims. Studies assessing contamination and adulteration rates in supplements have found rates ranging from 12% to 58%.

There are, fortunately, a few trustworthy organizations that independently test supplements:

  • S. Pharmacopeia (USP)
    Look for: USP Verified
  • NSF International
    Look for: NSF Certified or NSF Certified for Sport
  • ConsumerLab.com
    Look for their certification on products that have been tested.

These certifications indicate that the product has been tested for label accuracy and screened for harmful contaminants.

Still, even with third-party testing, the interactions between multiple supplements and multiple medications remain largely unknown. This is important because 25% of Americans take three or more prescription medications—and adding supplements on top of that creates an unpredictable mix.

In the end, the safest approach remains the simplest:
The best medicine is as little medicine as possible. The best prescription is exercise.

Dr. Charlie Barnett is a contributor to KnoxTNToday, where he writes a weekly column, DocTalk, sharing his expertise on health and wellness management.

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