March 2, 2020

Supplements: They’re Not As Safe As You Might Think

Manufacturers don't have to prove benefit or disclose risk

Man in drugstore choosing supplements

“What side effects should I be watching for?”


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This is one of the first questions people ask when prescribed a new medication – and for good measure.

The Food and Drug Administration (FDA) has guidelines that require manufacturers to disclose side effects of prescription medicine. This is meant to inform the prescribing physicians and the patients taking the medicine about the risks and benefits of these substances. Drug advertisements even require that manufacturers disclose side effects of the medicine, along with the benefits that clinical trials have demonstrated.

But, these disclosure requirements are not the same for vitamins and supplements. For these, the FDA requires that they are generally safe and that the labels are not “misleading.” But proof of benefit and disclosure of risk is not required from the manufacturer.

“It’s recommended to always talk with your doctor before taking any sort of supplement,” explains internal medicine specialist Ronan Factora, MD. “Unregulated supplements can pose a serious risk if taken with other medicine, in excessive amounts or taken for an unconfirmed medical problem.”

But it’s not all bad news. In certain scenarios, adding a supplement into your wellness routine can tout some health benefits. Adding in some extra vitamin D during the dreary winter months or supplementing with a protein shake when you’re on the go typically won’t do you any harm.

But it’s recommended to work with your primary care doctor prior to taking any supplement. They can look at the product and evaluate and analyze it based on data and research – not from what the label is claiming it can do.


Still, it’s always best to get the majority of your nutrients and minerals from real food, not supplements.

Can supplements cause health problems?

Lack of knowledge about the risks of supplements can sometimes lead to potential and unforeseen problems.

Vitamins are generally considered safe by the general public and used by a large percentage of the population. In one survey, half of the people age 50 to 64 took vitamins, which rose to 68% in those 65 and older. Though vitamin C and vitamin B12 are generally considered safe in any amount, excessive amounts of certain vitamins are associated with harm.

Some harmful side effects include:

  • Excess vitamin A has been associated with higher risk of osteoporosis.
  • Excessive amounts of vitamin B6 can produce peripheral neuropathy.
  • Vitamin E in doses greater than 400 units daily has been associated with a higher risk of all causes of death.

Though it’s relatively easy to look at a single supplement to see how much of a vitamin you’re taking, this becomes more difficult to track when you’re taking multiple supplements – particularly when the products contain multiple components or proprietary blends.

Can supplements interact with prescription medication?

For herbal supplements, it’s worthwhile to know how they could potentially interact with other supplements and, more importantly, with prescription medication.


“Garlic, ginger or ginkgo extracts could potentially interact with blood thinners and increase the risk of bleeding,” says Dr. Factora. “And St. John’s Wort is commonly taken for depression, but it can interact with other antidepressants being taken at the same time.”

Herbal extracts and supplements are often metabolized in the liver and some may have a direct impact on the metabolizing of prescription medications.

Extracts and supplements can even cause medicines to last longer than they’re intended to or can reduce the amount of time they’re effective.

Supplements that have been known to negatively affect liver metabolism include echinacea preparations, kava, certain types of cinnamon and maleleuka. Medications that could potentially be affected include statins, which are used to control cholesterol, and a number of antidepressants and anti-seizure medications.

“Speaking with your doctor can help determine potential interactions,” says Dr. Factora. “Often, asking the pharmacist about any specific concerns you have about a new supplement is worthwhile, too. It’s always better to be safe than sorry.”

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