Americans seem to have quite a positive view of dietary supplements. According to a 2023 survey, 74% of U.S. adults take vitamins, prebiotics and the like.

The business of supplements is booming, and with all the hype around them, it’s easy to forget what they actually are: substances that can powerfully affect the body and your health, yet aren’t regulated like drugs are. They’re regulated more like food.

Thanks in large part to a 1994 law, the Food and Drug Administration is essentially toothless when it comes to supplements. As the agency acknowledges: “FDA does not have the authority to approve dietary supplements before they are marketed. Companies can sell supplements without going through any sort of approval process, or even having to share safety evidence.”

As a research faculty member in graduate medical education, I’m responsible for teaching resident physicians how to understand and critically engage with health research. I also write about health, wellness and supplements for a broader audience. As a result, I spend a lot of time thinking about supplements.

It’s important to consider why so many people believe supplements can help them lead a healthier life. While there are many reasons, how supplements are marketed is undeniably an important one. In my years following the industry, I’ve found that three mistaken assumptions appear over and over in supplement marketing.

The appeal to nature fallacy occurs when you assume that because something is “natural” it must be good. The word natural is used a lot in the marketing of supplements. In the context of health, it often feels right to want natural medicine, remedies, prevention techniques and so forth.

For example, if I say “vitamin C,” what do you immediately think of? Probably oranges or citrus in general and flu prevention. But if I say “the flu shot,” what immediately comes to mind? Probably doctor’s offices, a little bit of pain and pharmaceutical companies. One of these is clinically proven to prevent flu infections and lessen the severity of illness. The other has been marketed as though it does those same things, but there’s no clinical evidence to support this.

The supplement industry is awash with brand names that incorporate the word “nature,” invoking the appeal to nature fallacy. Also, look at websites and advertisements that urge customers to forgo “artificial” products in favor of “pure” and “natural nutrition.” Using the word artificial to describe other products and natural to describe a specific supplement is intended to make you feel like that product will be superior to the competition and that you need it to be healthy.

To be clear, “natural” does not equate to “better,” but that’s what the marketing wants you to think.

There’s another assumption that piggybacks on the appeal to nature fallacy: If something is natural, it must be good, and more of it must also always be better. If a little vitamin C is good for us, then a lot of it must be great!

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