What Is Actually Inside Dietary Supplements

In 1993, a SWAT team equipped with night-vision goggles and assault rifles surrounded Mel Gibson’s mansion under the cover of darkness. They burst into the home, eventually finding the movie star wearing a bathrobe in his kitchen. Gibson put his hands up and the agents cuffed him immediately, over protestations that he had done nothing wrong, and certainly nothing dangerous. His crime? The possession of vitamin C tablets. “You know, like in oranges,” Gibson reminded the agents—and the viewers.

This was a television commercial. In a dead-serious voice-over, the ad, which was backed by the dietary-supplement industry’s advocacy arm, claims that the federal government wants to classify your humble multivitamin capsules as drugs, a word loaded enough in the early ’90s to evoke crack instead of ibuprofen. The ad ends with a stark warning on a black screen: Viewers should contact the United States Senate to protect their freedoms. If they didn’t, their home could be raided next.

The campaign was a huge success, according to Catherine Price, the author of Vitamania: How Vitamins Revolutionized the Way We Think About Food. At the time, the government was considering a bill to loosen the FDA’s regulatory reins on supplements, ensuring, among other things, that their makers would never have to prove their products’ safety or efficacy before marketing them to the public. People really did contact their senators en masse, Price told me, and the bill passed easily. The change rewrote the future entirely for the makers of dietary supplements—a category of products commonly referred to as vitamins but that also includes minerals, herbs, amino acids, and other “dietary substances.” From 1994 to 2016, the number of products on the American supplement market grew from about 4,000 to about 80,000; by one estimate, the market was worth more than $43 billion in 2019. As people have looked for ways to fortify their immune system during the coronavirus pandemic, the industry has grown even faster.

When you walk down the vitamin aisle at Walmart or type your symptoms into Google, you’re now met with the infinite constellation of marketing opportunities this law created. This is true no matter what ailment you’re trying to address or corporeal obstacle you’re trying to overcome. Synthetic vitamins are combined with one another and with a slew of other substances in seemingly limitless permutations, sold by familiar consumer brands or movie stars or venture-backed start-ups in many different dosages and formats. There are now dietary-supplement blends advertised for focus, for combatting fatigue, for hair growth, for weight loss, for sexual potency, for surviving a hangover. The variety is overwhelming, as are the promises in all of those little capsules. But if you’re confused, don’t be: There’s a pretty good chance that whatever is lurking underneath all that promise is pretty similar to your average multivitamin.

For the average person, vitamin is a slippery term. It denotes an invisible thing hiding in your food, a type of aisle at the drugstore, a product hawked by bland women on Instagram and angry men on YouTube. Multivitamin is similarly slippery, and more a term of art than a term of science. On an etymological level, it refers to any supplement that contains more than one vitamin. But according to Carol Haggans, a dietician and consultant at the National Institute of Health’s Office of Dietary Supplements, there is no regulatory standard for what multivitamin means, for what one must contain, or for what should be labeled as such. What the buying public tends to think of as a multivitamin usually contains all or part of a person’s recommended daily intake of actual vitamins (researchers have identified 13 essential to human health, and they’re the familiar ones: C, D, all the Bs), in addition to a number of minerals (iron, zinc, magnesium), and sometimes other non-vitamin substances such as ginger and ginkgo.

Then there are the other multivitamins—the pills that make all the promises. These products, which claim to naturally “support” (we’ll talk about this word later) an even skin tone or jump-start productivity or calm nerves, almost always seem separate from the Centrum Silver that Grandad takes or the Flintstones chewable that appeared next to your childhood cereal bowl every morning; rarely will you find the word multivitamin on their labels or in their product descriptions online. But at a nutritional level, it’s often hard to see where these sorts of products are distinct.

The luxury wellness company Moon Juice markets a hair-growth supplement that includes all 13 essential vitamins in doses similar to or exceeding those of common multivitamins, as well as minerals that are almost always present in such vitamins: iron, iodine, zinc. (Moon Juice did not respond to a request for comment.) H-Proof, a supplement that claims to proactively ameliorate the effects of hangovers, contains significant levels of nine vitamins, plus zinc and potassium. (Rachel Kaplan, H-Proof’s co-founder, told me that the company’s supplement is patented and therefore distinct from others on the market. She said the supplement is safe to take with multivitamins.) The list goes on and on: Boost your immune system! Support your digestive health! Increase productivity! Even dietary products like 5-Hour Energy shots have a significant ingredient overlap with multivitamins—although, presumably, your multi doesn’t also include more than 200mg of caffeine.

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Other companies take a different path to a similar destination, with vast product lineups that are positioned as complementary and customizable—an alternative to one-size-fits-all traditional health care. Hum Nutrition, whose products are sold at Sephora and Bloomingdale’s, offers a cover-your-bases multivitamin as well as a broad assortment of products that shoppers can use to build their own personal health routines. These ancillary products have names like Uber Energy and Hair Sweet Hair, and many of them include blends of vitamins and minerals already found in the company’s multivitamin, sometimes with other herbs or extracts mixed in. Other add-ons are just standard-issue vitamin D or biotin supplements, rebranded as Here Comes the Sun or Killer Nails. Care/of, a line of dietary supplements available at Target, offers a smaller but structurally similar setup, with a standard multi for men or women and add-ons for focus or energy or immunity. You can buy a multivitamin, and then build your own multivitamin, perhaps unwittingly, to take on top of it.

Graham Rigby, Care/of’s chief innovation officer, told me via email that the brand’s mix-and-match line is formulated to fall below any known safety limits for its ingredients. Shauna Aminzadeh, a spokesperson for Hum Nutrition, told me that the company’s build-your-own vitamin regimen is “targeted to very specific health and beauty concerns” and that “key ingredients are backed by clinical trials.”

Cross-referencing products’ ingredients against one another is an exhaustingly detailed process. The print is tiny, the numbers are very close together, and different manufacturers list the same ingredients in different orders and under different names. If you’re shopping online, some websites won’t let you zoom in far enough to easily read the ingredient lists. Nothing about how supplements are marketed or packaged makes them easy to understand or compare for the people buying them. The regulatory changes passed in 1994 mean manufacturers are not required to disclose much at all, including potential side effects and drug interactions. If they claim clinical proof of their products’ efficacy, they are not required to make that proof available for scrutiny, or even to demonstrate that it exists. This system is how you end up with people stacking supplements on top of one another with no real understanding of what’s in them, and no real understanding of what to expect.

According to Tod Cooperman, the founder and president of ConsumerLab.com, which conducts independent lab testing on retail dietary supplements, the end experience for buyers often looks similar, even if they select different products from different brands: They are taking at least one multivitamin, and maybe the equivalent of several. “What you typically see is that marketers are formulating products based on the smallest scraps of evidence for an ingredient that might relate to a condition,” he told me. “There’s the expectation that the products are going to contain many ingredients if there’s some magic to the formula, and obviously, that is what [the marketers] are shooting for.”

Because consuming a minimum amount of certain vitamins and minerals is essential to human life, there are studies linking all of them to a slew of bodily processes. That means supplement marketers can advertise their products as supporting or encouraging (importantly, not causing) healthy immune function or clear skin or good mood, even if there’s no proof that taking large amounts of these substances leads to any additional effect. Vitamin C, for example, is indeed important for your immune system, and it figures prominently in many of the immunity-boosting supplements that have become especially popular during the pandemic. But as with all vitamins and essential minerals, infinite Vitamin C is not infinitely beneficial. Consuming it is helpful only to a point that most people hit through their diets, Haggan, the NIH dietician, told me. That point is far lower than the megadoses included in many immunity supplements.

Where supplements make a real difference is in people with genuine nutritional deficiencies or with specific health conditions, Haggan said. For example, pregnant people need to get more folic acid than the average person in order to prevent some birth defects, and vegans often don’t get enough B12. People with enough money to build bespoke personal supplement regimens rarely have deficiencies. Most Americans, for that matter, get everything they need by eating and going outside. Beyond the known essential nutrients, we have even less understanding of what—if anything—other supplement ingredients do, and in what amounts they might do it. Small studies abound, many of them conducted on rodents instead of humans. Although this type of research is crucial to scientists, Haggan said, it in no way proves that a particular effect can be extrapolated to humans through use of any particular consumer product.

This is the part where discussion of supplements gets tricky. Most dietary supplements are unlikely to hurt an otherwise healthy person in the short term, Haggan said, even if they contain megadoses of certain ingredients. In a country where the health-care system is so often inaccessible and unreliable, isn’t it good that lots of people want to do what’s in their power to shore up their personal health outside of that system? Isn’t it good that vital nutrients are widely available and pretty affordable? Who cares if some people treat vitamins like edible astrology? Americans, as Mel Gibson told us all those years ago, want the opportunity to decide for themselves what goes in their bodies.

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The problem is that the supplement industry, as it stands currently, ensures that making good personal choices with its products is almost impossible. Because even the most basic proof of a product’s efficacy and safety isn’t required in order to start selling, that research isn’t done. Cooperman told me that about one in five of the supplements that ConsumerLab tests is substantially different than what it claims to be. The ingredient levels are much too low or much too high. The pills don’t break apart to allow their ingredients to be absorbed by the body. The oil-based capsules go rancid. Some supplements are tainted with pesticides, metals, or actual pharmaceuticals. Price recounted an anecdote she heard from a chemist during her Vitamania reporting: While evaluating a male-enhancement supplement that was supposed to contain a traditional mix of Chinese herbs, the chemist cracked open a capsule and a chunk of a blue Viagra tablet fell out. (In the male-enhancement world, this kind of thing is more common than you might expect.)

Supplements can be dangerous. If you pile a few different types on top of one another, and then pile those on top of the vitamins and minerals you’re already getting from food—itself commonly fortified or enriched with extra vitamins in the United States—you could very well be megadosing lots of different substances without realizing it. In the short term, with most supplement ingredients, that’s probably fine—they are water-soluble, which means you’ll excrete the excess in urine. But for fat-soluble vitamins such as A, D, and E, as well as minerals such as calcium and iron, according to Price, the overage can accumulate in bodily tissues over time. That helps make multivitamins an overdose risk and can cause serious problems—hair loss, fainting, cardiac issues, seizures, coma, and even death. One recent survey found that one in eight people said either they or a member of their immediate family had experienced a severe side effect after taking a dietary supplement.

These conditions attract bad actors. Multilevel marketing schemes, conspiracy theorists, and celebrities looking to diversify their revenue streams are all serious players in the American supplement market, many of them hawking products that are extraordinarily similar to one another, just with different packaging and a different pitch. Caveat emptor doesn’t seem to cut it, but maybe this will: Whatever it is that sounds so promising might just be a multivitamin, and when was the last time one of those changed your life?