In the last 30 years, our collective relationship with supplements has morphed into a full-blown obsession: More than half of adults in the United States today take supplements to “treat” nearly every health issue or psychological woe under the sun. TikTok creators guzzle berberine to “speed up” their metabolism, celebrities swallow sea moss for gut health, and biohackers take curcumin for longevity. 

Supplements may seem like a shortcut to a better mood or ripped physique, but emerging evidence suggests these compounds can harm more than help. Over the last quarter century, scientists have seen a stark rise in liver injury and liver failure linked to supplement use. Patients are showing up to clinics with less severe side effects, too, including mood swings, gastrointestinal issues, fatigue, kidney stones, hair loss, and high blood pressure.

Behind this troubling trend are three key factors: the rise of supplements containing especially toxic compounds, harmful drug interactions, and a phenomenon known as “megadosing,” or taking well beyond the recommended limit.

(5 things you should know before trusting that supplement.)

“Everyone is searching for the magic bullet and the elixir of youth— something that’s very easy to be popped as a pill to slow down the aging process or prevent chronic disease,” says JoAnn Manson, a physician, epidemiologist and endocrinologist at Brigham and Women’s Hospital in Massachusetts and a professor at Harvard Medical School. 

Eighty-four percent of consumers are confident these products are safe and effective. However, most of the tens of thousands of supplements on the market have not been tested for efficacy or safety. “It’s a Wild West out there, so buyer beware,” Manson warns.

Humans have harnessed botanicals, herbs, plants, minerals, and metals to treat illness or improve general well-being for thousands of years. But now, ingredients that were once steeped in ancient wisdom fill pharmacy shelves and social media feeds—often in the form of tablets, capsules, soft gels, powders, bars, gummies, and liquids. 

We have a global diet-related disease crisis and people are really sick, broken and suffering. Patient polls suggest 52 percent of individuals in the United States feel their symptoms are “ignored, dismissed, or not believed” when seeking medical treatment. The traditional Western medical system is “failing them,” Mozaffarian adds, so many turn to natural “do-it-yourself” medicine, which often includes supplements. 

For certain health conditions, deficiencies, and life stages, targeted supplementation can be beneficial. Pregnant women take folic acid to prevent birth defects, while older people often benefit from additional B12. Evidence suggests omega-3s can support heart health and probiotics can relieve irritable bowel syndrome. Scores of studies support these uses, but the majority of other claims don’t live up to the hype. 

There is no compelling data that herbal supplements are needed to maintain general health. It gets trickier to come up with a one-size-fits-all answer when individuals are trying to address a specific malady or therapeutic intent. For most people, taking common dietary supplements at the recommended dose is safe and doesn’t pose serious health risks. They’ll simply make “expensive urine,” Mozaffarian says.

But certain supplements—and certain doses—require extra caution.

When to beware of supplements

As the supplement industry has grown to meteoric heights, so have the downstream side effects: 20 percent of drug-induced liver injury in the United States is now related to herbal and dietary supplements, with some analyses putting the number as high as 43 percent. Meanwhile, the number of people on the U.S. transplant list with drug-induced liver failure related to supplements rose from one to 7 percent between 1995 and 2020. This is a massive uptick—a seven-fold increase—over 25 years.

Recent media reports spotlight patients ending up in the emergency room with yellow eyes, abdominal pain, fatigue—symptoms of liver failure linked to supplement intake, even from reportedly “clinically-validated” brands. 

Certain supplements have been linked to these effects, including green tea extract, often found in weight-loss supplements or metabolism “boosters;” bodybuilding supplements sometimes tainted with anabolic steroids; and multi-ingredient nutritional supplements used for a range of purposes from hair growth to mental health. 

These ingredients are common: In 2024, researchers found that 15 million Americans take compounds known to be toxic to the liver: turmeric, ashwagandha, black cohosh, garcinia cambogia, green tea, and red yeast rice. (The benefits—and downsides—of taking ashwagandha.)

While things like simple vitamins and minerals are generally okay, with some points of caution [niacin can be hepatotoxic in high doses], I would generally avoid anything with herbal or botanical ingredients.

These offending agents impact health in myriad ways: Green tea extract can inflame the liver, while bodybuilding supplements can slow or stall bile fluid. Multi-ingredient supplements are trickier to study health-wise, as it’s difficult for scientists to isolate their active components.     

Mislabeling and adulteration run rampant across the supplement industry, too, making it challenging to pinpoint side effects. Users often mix and match supplements with multiple bioactive ingredients, sometimes taking them at super-high doses or with other drugs, while manufacturers swap in cheaper ingredients to lower costs. 

In rare cases, analyses have revealed supplements contaminated with heavy metals like lead and arsenic, synthetic drugs, bacteria, yeast and fungi—agents which are linked to dementia, infection, brittle bones, and appendicitis, especially in the elderly or those with compromised immune function.

Bigger doses aren’t better for you

Megadosing, when consumers take micronutrients exceeding the recommended dietary allowance or more than advised by their health provider, is also risky—especially when the compound is fat-soluble and builds up in the body. 

When it comes to supplements, higher doesn’t necessarily mean better.

(Why taking vitamins A and E can do more harm than good.)

High doses of vitamins can interfere with the body’s normal processes, Mozaffarian explains, leading to side effects like gastrointestinal symptoms, headaches, heart palpitations, or insomnia. Women may be especially vulnerable to the toxic effects of megadosing due to smaller body sizes and differences in metabolism and immune function. 

Importantly, reactions are also based on individual genes or immune systems, Ghabril explains. Green tea extract might be totally fine for one person yet cause serious harm for another. 

The evidence is clear that herbal and dietary supplements can cause liver injury just like prescription drugs can. There is a clear unmet need for our population’s well-being and safety when it comes to their marketing and use.

How to choose a better supplement

How did it get to be this way? For one, the FDA doesn’t regulate dietary supplements in the same way as it does prescription or over-the-counter drugs. Supplement-makers don’t have to prove their products are safe or effective before entering the market. That means consumers can’t be sure what’s in the bottle or exactly how it might affect them. It’s really unfortunate that, in the U.S., supplement companies can make millions of dollars in profits without testing their agents. We should require them to use some portion of their profits to show that their products work.

With over 80,000 unique products sold, it’s challenging to distinguish high-quality products from low. But Manson and Ghabril direct consumers to draw on trusted resources such as the NIH Office of Dietary Supplements or LiverTox database.

If you are considering taking supplements, Manson, Ghabril, and Mozaffarian all say: Talk to your doctor, source supplements from a reputable provider with third-party testing, avoid megadosing, cross-check any potential drug interactions or contaminations, and don’t expect a miracle. 

Supplements can’t substitute for a balanced diet and healthy lifestyle factors like exercise and sleep. And that’s ultimately the real key to improving your health. The magic formula for a long, healthy life is well-known: a healthy diet of minimally-processed foods, mostly plants, plenty of exercise, sleep, low stress, avoidance of drugs, and meaning in life. We need to get our vitamins from food.”

These core tenets may not seem as sexy as the ‘miracle-in-a bottle’ supplements, but they work.