Doctors Warn: Common Daily Supplement Mistake Could Harm Your Health

About 75% of Americans take some kind of supplement regularly, making it a common practice in the U.S.

If you’re part of that group, it’s understandable to wonder about your own supplement intake after seeing yet another person rave on social media about how taking a particular nutrient changed their life. Some supplements have data to support their positive health impacts on things like sleep and mood, which can make navigating this even more confusing.

If you’re dealing with a health concern or just don’t feel like yourself, taking a supplement probably seems like a good idea—and it very well may be. But this can be a tough area of health to navigate. “Dietary supplements are available over-the-counter and without a prescription, which often leads people to believe that they are safe,” says Dr. Kelly Johnson-Arbor, M.D., a toxicologist at MedStar Health. 

Couple that with the fact that supplements aren’t tightly regulated by the Food and Drug Administration (FDA), and doctors have some concerns. “Even though the reported benefits of some dietary supplements are marketed heavily on television, the internet and social media, these claims may not always be backed up by scientific evidence,” Dr. Johnson-Arbor says. But there’s one common daily supplement mistake that she and other doctors say they keep seeing people make that’s especially troubling.

Whether you’re considering taking a new supplement or are already on one, doctors say it’s important to be aware of this very common—and potentially serious—mistake. 

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This Is Hands-Down the Biggest Daily Supplement Mistake Doctors See People Make

It’s taking a new supplement without talking to your doctor first. While they often seem harmless, “supplements can have significant drug interactions,” says Dr. Jamie Alan, Ph.D., an associate professor of pharmacology and toxicology at Michigan State University. 

Dietary supplements can have serious side effects, including liver damage, Dr. Johnson-Arbor points out. “They can contain contaminants, and may also interact with other medications.”

Related: The One Supplement To Avoid if You’re a Woman Over 50, According to a Gerontological Nutritionist

Beyond that, there’s likely a reason you’re taking a supplement—and you’re not getting it checked out if you’re hoping it will go away with supplements, says Dr. Daniel Chandler, M.D., primary care physician at Tufts Medical Center. “If you’re taking a supplement, it’s probably due to a symptom or side effect that you have undiagnosed,” he says, noting that taking a supplement instead of seeing a healthcare provider will only delay your care and increase the odds that the underlying issue will get worse.

Ultimately, doctors want you to check in with a licensed healthcare provider before taking a new supplement. “I would recommend checking with your healthcare provider or pharmacist before starting to avoid any potentially concerning interactions,” Dr. Alan says. 

Related:I Took Magnesium Before Bed for 6 Months and It Completely Transformed My Sleep

Some Supplement Ingredients Are More Concerning Than Others

The most concerning supplement ingredients are those with potential drug interactions or that have their own side effects. “Some dietary supplement ingredients can interfere with how the human body processes, or metabolizes, medications,” Dr. Johnson-Arbor says. “This means that the use of certain supplements can increase or decrease the effectiveness of other medications, potentially leading to toxicity or ineffective treatment.”

St. John’s Wort is one of the most concerning supplements doctors flag for this reason. “It can interact with numerous medications, including blood thinners and oral contraceptives, leading to an increased risk of bleeding or unintended pregnancy,” Dr. Johnson-Arbor explains.

Calcium supplements can interact with levothyroxine, bisphosphonates (like alendronate and ibandronate), and certain types of antibiotics, leading to reduced absorption and decreased effectiveness of the prescription medications, according to Johnson-Arbor.

Even garlic supplements can increase bleeding risk, and ginseng can interact with blood thinners, Dr. Chandler points out. Further, a vitamin K supplement may reverse the impact of warfarin, a common blood thinner, making it less effective, Dr. Chandler says. Even biotin, which plenty of people take to support hair and nail growth, can mess with medical testing. “If you’re taking a lot of biotin and we test your kidney function, it will make your kidneys look worse than they actually are,” he notes.

Unfortunately, those are just a few to be wary of. “There are others, too,” Dr. Alan says.

Related: Gastroenterologists Are Begging People To Avoid This One Common Fiber Mistake

Is It Ok To Take Multivitamins Without Talking to Your Doctor?

Multivitamins seem pretty mild, and Dr. Alan says they generally are. “Most multivitamins have very minimal drug interactions and should not be a problem for most people,” she says.

Most components in a multivitamin are water-soluble, which means you’ll pee out anything you don’t need, Dr. Chandler says. “It may be a waste of money, but generally not much harm,” he says.

Still, if you’re taking medication, it’s always a good idea to talk to a doctor before taking any kind of new supplement, even a multivitamin. “Even the benign-sounding vitamins and minerals found in multivitamin supplements can interact with certain medications,” Dr. Johnson-Arbor says.

Overall, doctors just want you to be open with a healthcare provider about your supplement use, whether it’s a multivitamin or a specific nutrient. “I’m worried about drug interactions and your kidneys,” Dr. Chandler says.

Up Next:

Sources:

• Jamie Alan, Ph.D., an associate professor of pharmacology and toxicology at Michigan State University

This story was originally published by Parade on Feb 14, 2026, where it first appeared in the Health & Wellness section. Add Parade as a Preferred Source by clicking here.