Surprising Liver Dangers of Herbal Products

1. Ask Your Doctor About an Herbal Product of Interest Before Taking It

“People should talk about herbal remedies with their doctor prior to starting, particularly if they are not familiar with the ingredients of the herbal remedy,” says Dr. Kushner. And if you’re already using something? It’s crucial to give your doctor a full list of what you’re taking, including herbal teas or supplements. Knowing what you’re taking will help your doctor recognize side effects. If your primary care doctor or specialist can’t provide the answers you’re seeking, seek a second opinion from an integrative medicine board-certified doctor or trained specialist.

2. Beware of the Big Liver Offenders

When it comes to supplements, the simpler, the better. “If you find a bottle with a long list of italicized words in the ingredient list naming the multiple herbs that are components in the particular supplement, I would steer clear,” says Kushner.

Green tea extract, anabolic steroids, and multi-ingredient nutritional supplements are among the top products that can cause liver injury, according to one review. “It is important to know that many different types of herbs can cause liver injury in an unpredictable way — for example, Herbalife and other weight loss herbal supplements have caused liver injury in many people,” says Kushner. Other research highlights reports of acute liver injury by those taking Herbalife products, but the specific ingredients that caused the damage are still unknown.

Certain herbs used in traditional Chinese medicine have also been found to pose some risks. Research has identified 28 traditional Chinese medicine herbs and herbal mixtures that have been reported to cause liver injury.

Meanwhile, comfrey contains several pyrrolizidine alkaloids that may cause liver injury when taken orally, according to a report in LiverTox. In addition, chaparral, kava kava, and skullcap can also damage your liver, according to LiverTox.

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3. Investigate the Ingredients List of an Herbal Remedy Before Trying It

Before buying, read the back of the bottle to see what’s actually inside the supplement. Some herbal products, such as milk thistle, for example, are known to be safe and could even play a role in treating certain liver conditions, according to the Mayo Clinic.

Still, you’ll want to talk to your doctor before taking any supplement product. Also, keep an eye out for additional ingredients: Green tea extract, for example, is added to many herbal products. And you’ll want to avoid big claims on the label. In some cases, supplements don’t list the ingredients at all but make claims that they will flush your liver. According to Johns Hopkins Medicine, liver cleanse supplements aren’t recommended — not only is there no evidence showing they work, but they can actually cause damage to the liver, they say.

4. Check the LiverTox Website for Background Information on Remedies 

Run by the National Institute of Diabetes and Digestive and Kidney Diseases, LiverTox contains valuable information on hundreds of drugs that have been found to damage the liver, including herbal products. If you’re looking to buy a new supplement (or if you already have a supplement in your medicine cabinet), check its ingredients on this regularly updated site to see if it can damage your liver. You’ll also, of course, want to run it by your doctor before you start taking a supplement.

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5. Turn to Independent Labs That Certify Quality Supplements 

According to the Harvard T.H. Chan School of Public Health, herbal supplements are largely unregulated in the United States. Therefore, it’s unknown how pure the substances may be — and what effects they may have on the liver, Dr. Halegoua-De Marzio says. That means labels may mislead consumers like you.

For example, black cohosh is often taken for menopause symptoms like hot flashes and night sweats, notes the National Institutes of Health’s Office of Dietary Supplements. But products labeled as black cohosh have been linked to more than 50 cases of liver injury, according to LiverTox, and some cases have been so severe that they resulted in liver transplants and even death. In several of those cases, though, scientists found herbs from the Chinese actaea species in the supplement rather than black cohosh, and this mislabeling may have been the culprit, LiverTox notes.

In addition, herbal supplements can contain mystery pharmaceutical ingredients. For example, one study found unapproved pharmaceutical ingredients in a whopping 776 dietary supplements, which were often marketed as weight loss, sexual enhancement, or muscle-building products.

If your healthcare team green-lights taking a certain supplement, work with them to choose a brand that has been tested by an individual lab, such as ConsumerLab, NSF International, or U.S. Pharmacopeia, Harvard Health Publishing notes. These companies independently certify supplements for dosage accuracy and safety.

6. Work With Your Doctor to Identify Potential Drug Contraindications

Another reason to report any supplements you’re taking to your doctor: They could be working against your prescription medications. According to one review, almost 25 percent of U.S. adults say they are taking a prescription medication while also taking a dietary supplement. The authors recommend that people on any pharmacological therapy avoid St. John’s wort. This is especially true for anyone taking the newer hepatitis C medications, because research has shown this herbal remedy may worsen liver function in people on hepatitis C medications, and could even result in hospitalization.

Also, if you already have a liver issue, taking potentially risky supplements could make matters much worse. “Generally speaking, if you have a liver disease that is advanced — be it from hepatitis C or other causes — a superimposed liver injury from herbs can lead to significant worsening,” says Kushner. So as a reminder: “People should talk about herbal remedies with their doctor prior to starting, particularly if they are not familiar with the components of the herbal remedy,” she says. If you are managing a liver condition or are concerned about risks specific to the liver, consult a hepatologist.

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7. Limit the Number of Herbal Products You Take

Beyond toxicity, talk to your healthcare team to avoid potential interactions between any herbal products or supplements with each other. In general, though, less or none may be more.

Not to mention, supplements aren’t a substitute for a healthy diet or lifestyle, nor are they a replacement for a treatment plan your healthcare team has recommended, as Harvard Health Publishing points out. Instead, you might consider these remedies as a possible complement to more conventional approaches.

So rather than taking a supplement you’re not sure about, talk with your doctor or integrative medicine trained provider, learn all you can about it, and improve your health by making other lifestyle changes, like eating healthier, exercising more, and sleeping more.

Additional reporting by Marie Suszynski.