6 Popular Herbal Supplements Linked to Rare Liver Risks — and How to Use Them More Carefully

A 2024 survey study published in JAMA Network Open estimated that roughly 15.6 million U.S. adults — about 4.7% of the population — had used at least one of six botanicals with reported liver-safety concerns in the previous 30 days. The six were turmeric (usually as curcumin supplements), green tea extract, ashwagandha, Garcinia cambogia, red yeast rice, and black cohosh.

That number is about exposure, not injury. The same study didn’t track how many of those people developed liver problems, and the honest answer is: most won’t. But the reason researchers picked those six in the first place is that each one shows up in case reports, in the NIH’s LiverTox database, and in hospital hepatology consults often enough that liver specialists are paying attention.

And here’s the practical problem this article is really about: a lot of people who take these supplements never mention them to a doctor. They assume “natural” means your liver’s got nothing to worry about. That assumption — not the herbs themselves — is where the avoidable risk lives.

So what’s actually happening here? Six botanicals that millions of people take for joint pain, stress, weight loss, cholesterol, menopause symptoms — and a growing recognition that concentrated supplement forms can, in rare cases, cause liver injury serious enough to land someone in a hepatology ward. The point isn’t to scare anyone off herbs. It’s to get people talking to their clinicians about what they’re actually taking.

Why supplements and liver risk are getting more attention now

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Herbal and dietary supplements now account for a growing share of drug-induced liver injury cases in U.S. research networks — somewhere around 20% of hepatotoxicity reports in the DILIN (Drug-Induced Liver Injury Network) data, according to a review from NIH and AASLD researchers. The products that show up most often aren’t obscure Amazon finds from a brand nobody’s heard of. They’re mainstream botanicals sold at pharmacies, health-food stores, and supplement chains.

The tricky part — and it’s worth saying upfront because it shapes everything that follows — is that supplements aren’t regulated the way prescription drugs are. There’s no requirement to prove liver safety before a product hits the shelf. Labels don’t always match what’s inside. And multi-ingredient blends make it genuinely hard to know which component a liver is reacting to, even in a hospital setting.

None of that means these six supplements are dangerous for everyone. But it does mean the average person walking into a supplement aisle deserves more information than the label gives them.

Turmeric / curcumin

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Why people take it: Joint pain, inflammation, general wellness. Turmeric as a food spice has been used for centuries in Indian, Ayurvedic, and East Asian cooking and traditional medicine. That’s the whole-food, culinary version — not what most Americans are taking.

What the liver-risk evidence says: LiverTox, the NIH’s database on drug- and supplement-induced liver injury, now lists turmeric — specifically concentrated curcumin supplements — as an established cause of clinically apparent acute liver injury. The risk appears higher with products designed for better absorption: high-bioavailability formulations, especially those that include piperine (black pepper extract) or lipid-based delivery systems. A cup of turmeric tea or a curry isn’t the same risk profile as a 500mg curcumin capsule with piperine.

Safe way to think about it: Turmeric spice in food is generally considered safe by NCCIH. The concentrated supplements deserve more caution, especially long-term use and especially with medicines — the NCCIH flags possible interactions with blood thinners, diabetes medications, and some chemotherapy drugs.

Who should be especially cautious: Anyone on blood thinners or diabetes medications. Pregnant people (NCCIH specifically cautions against medicinal amounts during pregnancy). And anyone with existing liver issues or unexplained abnormal liver tests should talk to a clinician before taking concentrated curcumin.

Green tea extract

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Why people take it: Weight loss, metabolism support, antioxidant benefits. Green tea extract is the key word here — not green tea as a beverage.

What the liver-risk evidence says: This is probably the strongest signal in the group. LiverTox describes green tea extract as a well-established cause of clinically apparent liver injury, and the cases haven’t always been mild — some reports involve acute liver failure, transplantation, and death. The mechanism is linked to catechins, particularly EGCG, and the problem is almost entirely with concentrated extracts (pills, powders, weight-loss blends), not with drinking green tea.

Health Canada conducted its own safety review and concluded there’s a plausible link between green tea extract and rare, unpredictable liver injury — the kind that doesn’t seem tied to dose or duration in any simple way.

Safe way to think about it: If you drink green tea as a beverage, this isn’t about you. The risk is concentrated in extract products — especially the ones folded into weight-loss or “metabolism” blends. If you’re taking a green tea extract supplement and develop unexplained fatigue, nausea, or dark urine, stop and get checked.

Who should be especially cautious: Anyone with known liver issues, people taking multiple medications processed through the liver, and anyone using multi-ingredient weight-loss supplements that include green tea extract alongside other botanicals.

Ashwagandha

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Why people take it: Stress, anxiety, sleep, energy, fatigue. It’s an Ayurvedic herb that’s been marketed heavily in the adaptogen trend — and it works for a lot of people in terms of the calming effects they’re after.

What the liver-risk evidence says: LiverTox reports that ashwagandha has recently been implicated in rare cases of clinically apparent liver injury, often of a cholestatic or mixed pattern. The typical timeline: symptoms show up 2 to 12 weeks after starting. These cases are rare, but the pattern is consistent enough that LiverTox now includes ashwagandha as a probable rare cause.

Safe way to think about it: The “adaptogen” and “ancient Ayurvedic” framing shouldn’t function as a safety guarantee. Most people will take ashwagandha without liver issues — but if jaundice (yellowing skin or eyes), itching, or right-upper-abdominal pain appear within a few weeks of starting, those are reasons to stop and talk to a doctor.

Who should be especially cautious: This one has a specific, strong warning: LiverTox says people with cirrhosis or advanced chronic liver disease should avoid ashwagandha. That’s not a “maybe check with your doctor” — it’s a direct clinical caution.

Garcinia cambogia

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Why people take it: Weight loss. Garcinia cambogia (Malabar tamarind) has traditional food and Ayurvedic uses, but its modern supplement form is almost entirely about weight management.

What the liver-risk evidence says: LiverTox lists Garcinia cambogia products as a likely cause of rare but clinically apparent acute liver injury — and some of those cases have been severe, including liver failure and transplantation. The active compound, hydroxycitric acid (HCA), interferes with fatty acid synthesis, but the weight-loss evidence in humans is, to put it bluntly, inconsistent and underwhelming.

There’s an additional complication: Garcinia often appears in multi-ingredient weight-loss products that also contain green tea extract or other botanicals with their own liver-safety questions — so assigning blame to Garcinia alone isn’t always possible, but the pattern in case reports is hard to ignore.

Safe way to think about it: The benefit case is weak and the rare-safety-signal case is serious. That’s not a great tradeoff for something marketed as a weight-loss aid. If someone is already taking it without issues, the risk is still low — but the product deserves more caution than its “natural fat-burner” marketing suggests.

Who should be especially cautious: Anyone with existing liver concerns, anyone using multi-ingredient weight-loss stacks, and anyone who would instinctively dismiss a liver-injury symptom as “just a bug” while continuing the supplement.

Black cohosh

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Why people take it: Menopausal symptoms — hot flashes, night sweats, mood changes. Black cohosh has traditional Native American uses and a long modern history as a menopause remedy.

What the liver-risk evidence says: This one is genuinely complicated, and the evidence doesn’t point neatly in one direction. On one side: more than 50 reports of clinically apparent liver injury — some severe, including cases requiring transplantation — have been linked to products labeled as black cohosh. LiverTox assigns it a likelihood score of A (well-established cause).

On the other side: clinical trials involving more than 1,200 patients didn’t show liver enzyme elevations or clinically apparent injury. That’s not a small trial — it’s enough data to create real tension with the post-marketing reports.

The possible explanations include product mislabeling, adulteration, or contamination — meaning the liver-injury cases might involve something other than black cohosh itself, even though the bottle said black cohosh. Or it could be an idiosyncratic reaction that affects a small subset of people.

Safe way to think about it: Black cohosh isn’t in the “clearly dangerous” category. But it has a documented post-marketing safety signal that’s serious enough to mention to a clinician — especially for anyone taking it long-term for menopause symptoms.

Who should be especially cautious: People with existing liver concerns, anyone taking other medications processed through the liver, and anyone who’s been using black cohosh for an extended period without ever mentioning it at a checkup.

Red yeast rice

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Why people take it: Cholesterol management. Red yeast rice has legitimate roots in traditional Chinese medicine and as a fermented food, but its modern supplement form is functionally different because of one compound: monacolin K.

What the liver-risk evidence says: Monacolin K is chemically identical to lovastatin — a prescription statin. If a red yeast rice product contains clinically meaningful amounts of it, the product behaves less like a gentle herbal supplement and more like an unstandardized, unregulated statin exposure. That means statin-like risks, including possible liver injury, muscle damage, and kidney concerns.

And here’s the kicker: you can’t tell from the label what you’re getting. NCCIH cites an analysis showing monacolin K content varied by up to 60-fold across products. Some red yeast rice supplements have meaningful statin-level activity. Others have essentially none. The label won’t tell you which.

There’s also a contamination concern: some red yeast rice products may contain citrinin, a compound that can harm kidneys.

Safe way to think about it: Treat red yeast rice as a possible statin exposure, not as a gentle food supplement. If you’re taking it for cholesterol, your clinician needs to know — partly because the product itself carries statin-like risks, and partly because whatever it’s doing for your cholesterol should be tracked with labs, not guessed at from a supplement label.

Who should be especially cautious: Anyone already on a statin or other cholesterol medication (doubling up is a real risk), anyone with liver or kidney concerns, pregnant/breastfeeding people (NCCIH says not recommended), and anyone who assumes “natural” means “no side effects.”

Symptoms that should get your attention

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If you take any of these supplements — or really any concentrated botanical — and develop any of the following, don’t wait-and-see: yellowing of the skin or whites of the eyes (jaundice), dark or cola-colored urine, pale or clay-colored stools, severe unexplained fatigue, nausea or vomiting that doesn’t pass, persistent itching, pain or discomfort in the upper right side of the abdomen, or abnormal liver tests on routine blood work.

These are the classic signs of liver injury, and they matter whether the trigger is a prescription drug, a supplement, or something else entirely. The right move is to stop the supplement and call your doctor — or seek emergency care if symptoms are severe — and bring the bottle with you.

The “bring the bottle” rule

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If you end up at a clinician’s office or an emergency department with possible liver symptoms, physically bring the supplement bottle. Not a photo. Not a description. The actual container.

Here’s why: multi-ingredient products are common, brands reformulate without notice, and a product’s label might list piperine, monacolin K, or a concentrated extract that changes how a doctor evaluates the situation. Liver specialists trying to identify the cause of an injury need to know what you actually took — not what you think you took.

This is also true for routine visits. If you’re taking turmeric for your knees or ashwagandha for stress, put the bottle in your bag next time you see your primary care provider. The default shouldn’t be hiding supplements from the person managing your health.

A few things to keep in perspective

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Most people who use these supplements will not develop liver problems. The documented injuries are rare, and for several of the botanicals above, the true incidence isn’t known because reporting is inconsistent and products vary so much. This article isn’t meant to scare anyone into throwing out their supplement cabinet.

But the idea that “natural” means “nothing to tell your doctor about” is the thinking that turns rare risks into missed diagnoses. The six botanicals here aren’t obscure — they’re some of the most widely used herbal supplements in the country. The smart move isn’t avoiding them categorically. It’s using them with the same disclosure and symptom awareness you’d apply to any other substance that can affect your liver.

And if anything in this article made you realize you’ve been taking one of these for months or years without ever mentioning it — that’s the thing to fix. Not panic. Just tell someone who can put it in your medical picture.