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Strange Side Effects From Supplements and What You Need to Know

Dietary supplements can boost one’s health but they can also create unusual side effects in the body.

By Carina Woudenberg; Medically Reviewed by Dr. Ahmad Talha Azam
Jan 23, 2024 4:00 PM
Woman taking supplements
(Credit: Dean Drobot/Shutterstock)


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Dietary supplements fall into a sort of gray area. They often resemble medication —pill-shaped and sold in bottles with child-safe screw tops. Their labels might also suggest certain health benefits. However, unlike medication, the U.S. Food and Drug Administration (FDA) considers supplements to be a food and doesn’t give them the same scrutiny it devotes to drugs.

“The FDA does not analyze the content of dietary supplements until consumers complain about it,” says Lina Begdache, a registered dietitian and associate professor of health and wellness studies at Binghamton University in New York.

That said, sometimes it can be hard to attribute side effects that you experience with the supplements you’re taking, Begdache adds. Often side effects will be gastrointestinal in nature — maybe a little nausea or diarrhea which consumers might attribute to other things.

However, supplements — which encompass a whole slew of things from vitamins, minerals, amino acids, botanicals and herbs, among other things — can also cause side effects that are a little more unusual.

Strange Side Effects From Supplements

Vitamin D

Vitamin D is a fat-soluble vitamin essential to bone health and other body functions. Health professionals often recommend taking a vitamin D supplement, especially if you live in an area where you aren’t receiving enough of the vitamin through sun exposure.

However, too much vitamin D can raise the calcium levels in your blood, notes Kelvin Fernandez, internal medicine resident at Newark Beth Israel Medical Center. “This condition can then manifest as severe kidney problems or even heart abnormalities,” he says.

And while vitamin D is sometimes reported to help with brain fog, too much of it has also shown to cause confusion and apathy, among other issues.


Choline is another vital nutrient found naturally in eggs and seafood. The supplement has shown to carry a host of benefits including boosting memory, breaking down cholesterol and providing nourishment for beneficial gut bacteria.

However, an overdose of choline can give its consumer a fishy odor and can also cause excessive sweating, salivation and low blood pressure, notes Inna Yegorova, who provides research, development and regulatory services for professionals working in the dietary supplements and nutraceuticals industry.


In addition, Yegorova highlights niacin (also known as vitamin B-3) for sometimes creating an odd side effect. Niacin helps turn nutrients into energy and repair DNA. However, when taken in higher doses, it can lead to stomach trouble and even turn its consumer’s face bright red.

Another odd example can be found in glucosamine, a supplement that supports bone and joint health for people with osteoarthritis. However, it is also known to increase eye pressure.

Read More: What You Need to Know About Vitamin D and Supplements

Should You Take Supplements?

Begdache is generally a proponent of getting nutrients through diet over supplements.

“Mother Nature has put these in a really optimal amount,” Begdache says. “For example, fat soluble vitamins (A, D, E and K) are better absorbed in the presence of fat.Food with naturally occurring fat soluble vitamins also generally has fat.”

A women’s health study looked at the use of dietary vitamin and mineral supplements in older women over the course of multiple decades. It found that vitamin B6, folic acid, iron, magnesium, zinc and copper were linked to a shorter life span among the 40,000 women who participated in the study. On the flipside, the same study showed that consuming calcium potentially increased life span.

Another study estimates that more than 20,000 emergency department visits each year are attributed to dietary supplement use in the U.S. These are typically attributed to unsupervised children getting into supplements, swallowing issues with older adults and use of energy and weight loss supplements in young adults.

“When taking supplements, a consumer must be aware of the possibility of a bad reaction or side effect,” says Yegorova. Especially, Yegorova adds, when the consumer combines different supplements, mixes supplements with drugs, takes too high of a dosage, or takes supplements in place of crucial medication.

Still all of this is not to say that supplements don’t serve a valuable role in our collective health.

“In the last century, our understanding of supplements has made remarkable strides,” Fernandez says. “Initially, we saw them as simple remedies for deficiencies, but now we know they can play complex roles in preventative health, disease management, and overall well-being.”

Read More: Do Multivitamins Work and How Do You Know If You Need One?

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high quality sources for our articles, and our editors review for accuracy, and trustworthiness. The sources below were used in this article:

Read More: What You Need to Know About Vitamin C, Vitamin B, Turmeric, and Fish Oil/Omega-3

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