Several common supplements can raise liver enzymes, sometimes dramatically. Green tea extract is the single most frequently implicated herbal supplement in liver injury cases tracked in the United States, but it’s far from the only one. Bodybuilding supplements, high-dose vitamin A, kava, ashwagandha, and multi-ingredient products marketed for weight loss have all been linked to elevated ALT and AST levels and, in some cases, serious liver damage.
Understanding which supplements carry this risk matters because they’re sold without prescription and often perceived as inherently safe. In a large prospective U.S. study of drug-induced liver injury, herbal and dietary supplements accounted for a significant and growing share of cases, with anabolic steroids, green tea extract, and multi-ingredient nutritional supplements topping the list.
Green Tea Extract
Concentrated green tea extract is the most common single-ingredient herbal product linked to liver injury. Since 2006, more than 50 reports of acute liver injury with jaundice have been attributed to green tea extracts in the medical literature. The culprit is a group of compounds called catechins, particularly one that makes up the largest share of the extract. These catechins can trigger mitochondrial damage and the production of harmful reactive molecules in liver cells.
What makes green tea extract tricky is that the injury doesn’t follow a predictable dose pattern. It appears to be an idiosyncratic reaction, meaning it affects certain people based on their individual biology rather than simply how much they take. Research has linked this susceptibility to a specific genetic marker in the immune system, suggesting the liver damage involves an immune-mediated response. Some people tolerate the supplement fine; others develop enzyme levels that spike into the thousands. In documented cases, ALT values (a key liver enzyme) have reached 1,788, 3,131, and even higher, well above the normal range of roughly 7 to 56 U/L.
The injury typically looks like acute hepatitis, with a pattern of sharply elevated ALT and AST. It can recur faster and more severely if someone stops the supplement, recovers, and then starts taking it again. Drinking brewed green tea, which contains far lower concentrations of catechins than extract capsules, has not been associated with the same risk.
Weight Loss and Multi-Ingredient Products
Multi-ingredient nutritional supplements, the kind marketed for weight loss, energy, or general wellness, account for the largest category of supplement-related liver injuries. In one analysis of non-steroid supplement liver injury cases, 68% were caused by products containing multiple ingredients. Brand names that appeared repeatedly in case databases include Hydroxycut, Herbalife, Slimquick, Move Free, and Airborne.
The challenge with these products is identifying which ingredient caused the damage. Many contain green tea extract as one of several active components, and in roughly a quarter of multi-ingredient cases, green tea was believed to be the actual cause. Others contain garcinia cambogia, kratom, or proprietary blends where the exact composition is unclear. When a product lists 15 or 20 ingredients, pinpointing the source of liver injury becomes extremely difficult for both patients and clinicians.
Bodybuilding Supplements
Bodybuilding supplements pose a unique risk because some contain unlabeled anabolic steroids. These aren’t listed on the ingredient label, so you may not know you’re consuming them. Anabolic steroids cause a distinct type of liver injury that looks different from what green tea extract produces. Instead of sharply spiking ALT and AST, steroid-related injury tends to cause a progressive rise in bilirubin and alkaline phosphatase, with only mild ALT and AST elevations. This pattern, called cholestatic injury, reflects bile flow disruption rather than direct liver cell destruction.
Symptoms of steroid-induced liver injury often include deepening jaundice (yellowing of the skin and eyes) and intense itching. Biopsy findings in these cases typically show a combination of bile stagnation and dilated blood channels in the liver tissue, a pattern strongly suggestive of anabolic steroid exposure. The listed ingredients in bodybuilding supplements, things like creatine, beta-alanine, glutamine, and caffeine, are generally not the problem. It’s the undisclosed steroids that cause harm.
Vitamin A
Vitamin A is a well-established cause of liver injury at high doses. The recommended daily intake for adults is roughly 2,300 to 4,300 IU. Doses above 40,000 IU daily are considered toxic, though people with underlying liver disease may develop problems at lower thresholds, potentially above 50,000 IU in some estimates for otherwise healthy individuals.
Unlike the sudden reactions seen with green tea extract, vitamin A toxicity tends to build slowly. Chronic overuse, typically at about 10 times the recommended dose sustained over months to years, leads to a gradual constellation of symptoms: dry skin, cracked lips, joint pain, fatigue, depression, and abnormal liver tests. Over one to eight years of moderately high intake, vitamin A can cause serious complications including portal hypertension (increased pressure in the blood vessels feeding the liver), fluid buildup in the abdomen, and swollen veins in the esophagus. These complications can develop even before full-blown cirrhosis is detectable. The takeaway: vitamin A supplementation beyond the recommended dose carries real, cumulative liver risk.
Kava
Kava, widely used for anxiety and relaxation, has a complicated safety profile that depends heavily on how it’s prepared. In the South Pacific, where kava has been consumed as a water-based preparation for centuries, serious liver problems have been rare. The liver toxicity concerns emerged primarily in Western countries, where kava supplements are made using alcohol-based or chemical solvent extractions that pull out a different mix of compounds than traditional water preparation does.
Researchers have investigated whether specific active compounds in kava (called kava lactones) are responsible, but no single lactone has been definitively identified as the cause. Some evidence points to minor components in the extract, including certain flavokavains, which show higher cell toxicity in lab studies than the lactones themselves. The body also converts kava compounds into reactive byproducts that can deplete the liver’s natural protective molecules. Several countries, including Germany and parts of Europe, have at various points restricted or banned kava extract sales due to cases of liver failure.
Ashwagandha
Ashwagandha, a popular adaptogen used for stress and sleep, has been increasingly linked to liver injury in recent years. A case series from India documented eight patients with liver damage from pure ashwagandha formulations, and at least 14 additional cases exist in published medical literature. The most common symptom was jaundice, appearing in nearly 90% of cases, followed by intense itching in about 63%. Other presenting symptoms included fatigue and abdominal distension.
The injury pattern in ashwagandha cases tends toward cholestasis, meaning bile flow is disrupted. This is similar to the pattern seen with anabolic steroids, though the mechanism is different. Given ashwagandha’s rapid rise in popularity as a supplement for stress relief and athletic performance, these reports are worth noting even though the total case count is still relatively small compared to green tea extract.
Other Supplements on the Radar
Beyond the major players, several other supplements have appeared in liver injury databases:
- Black cohosh: used for menopause symptoms, linked to hepatitis-like liver injury
- Kratom: used for pain and mood, increasingly reported as a cause of elevated enzymes
- Valerian: a common sleep aid that has appeared in multiple liver injury reports
- Niacin (vitamin B3): particularly sustained-release formulations at high doses
- Red yeast rice: used for cholesterol management, contains compounds similar to statin drugs
- Fo-Ti (he shou wu): a traditional Chinese herb with multiple documented liver injury cases
- Garcinia cambogia: a weight loss ingredient found in many multi-ingredient products
How to Reduce Your Risk
The supplement industry in the United States is not regulated the same way pharmaceuticals are. Products can reach store shelves without proving safety or efficacy, and what’s on the label doesn’t always match what’s in the bottle. Bodybuilding supplements with hidden steroids are one example, but contamination and mislabeling extend across categories.
Third-party testing programs offer one layer of protection. Organizations like USP (United States Pharmacopeia) and NSF International independently verify that a supplement contains what it claims and is free of harmful contaminants. Looking for these certifications on the label won’t eliminate all risk, but it significantly reduces the chance of consuming something undisclosed.
If you’re taking any supplement and develop yellowing of your skin or eyes, unusually dark urine, persistent fatigue, nausea, or upper right abdominal pain, these are signs your liver may be struggling. Stopping the supplement promptly is critical. In many cases, liver enzymes begin improving within days to weeks of discontinuation, though cholestatic patterns from steroids or ashwagandha can take longer to resolve. The speed of recovery depends on the severity of injury and how quickly the offending product is removed.