What are the documented cases of liver injury linked to green tea extract or 'fat burner' supplements?
Executive summary
Medical literature and regulatory reviews describe dozens to over a hundred reported cases worldwide tying green tea extract (GTE) and multi-ingredient “fat‑burner” supplements to clinically apparent liver injury, including some that progressed to acute liver failure and liver transplantation; systematic reviews and national safety reviews find a small but reproducible signal, particularly with concentrated EGCG exposures and multi‑ingredient weight‑loss products [1] [2] [3] [4].
1. What has been reported: case counts and notable series
Published reviews and safety summaries document scores of cases: one literature review cited more than 200 reports of adverse events from green tea products, of which around 27 were judged possibly or likely caused by GTE (a 216‑case review cited by the Supplement Information Expert Committee) and other reviews and news reports place cumulative case reports on the order of dozens to over 80 worldwide [1] [2] [3]. Regulatory summaries from Health Canada identified 11 Canadian suspected cases reported between 2006 and 2016, though only a minority contained enough detail for full assessment [4]. Case series and single‑center reports document multiple episodes linked specifically to commercial “fat‑burner” products containing GTE, green coffee, spirulina or mixed herbal blends [5] [6].
2. High‑profile products and clusters
Several named products and product classes recur in the literature: Exolise (a GTE preparation) was withdrawn in Europe after 13 cases of hepatotoxicity, Hydroxycut formulations containing GTE drew U.S. FDA warnings and recalls in 2009 after several dozen adverse liver reports, and individual companies’ green‑tea fat‑burner formulations (e.g., Applied Nutrition, Irwin Naturals) appear in case reports and litigation narratives [2] [7] [8]. Many reports involve mixed‑ingredient “fat‑burner” supplements containing GTE alongside caffeine, Garcinia cambogia, and other botanicals, complicating single‑ingredient attribution [9] [2].
3. Severity spectrum and clinical outcomes
Reported clinical outcomes range from reversible transaminase elevations and self‑limited hepatitis to fulminant hepatic failure requiring orthotopic liver transplantation and, in rare instances, death; case reports and series document transplantations following fat‑burner or GTE‑associated liver failure as well as multiple hospitalizations for acute hepatitis [10] [5] [2]. Reviews note typical onset within weeks to a few months of starting high‑dose supplements and that most cases resolve after discontinuation, but a small subset progresses to severe liver injury meeting “Hy’s law” criteria [10] [1] [11].
4. What the evidence says about causality and mechanisms
Causality assessments in aggregated reviews judge a fraction of reported events as possibly or probably due to GTE, but attribution is frequently hampered by polyherbal products, incomplete case data, and variable dosing; a 216‑case review found 27 reports possibly/likely due to GTE [1]. Mechanistic and animal studies implicate high concentrations of EGCG (epigallocatechin‑3‑gallate) as hepatotoxic in susceptible contexts, with proposed pathways including mitochondrial injury, oxidative stress, and immune‑mediated idiosyncratic reactions—recent human genetics work points to HLA and UGT variants that may elevate risk, while clinical trials show transaminase rises at cumulative EGCG doses ≳800 mg/day [1] [8] [12].
5. Regulatory reactions and product quality concerns
Regulators and expert bodies have repeatedly flagged GTE; France and Spain banned Exolise after clustered cases, Health Canada updated safety information after reviewing international reports, and the U.S. FDA has issued consumer warnings during Hydroxycut investigations—yet surveillance data are limited and many reports lack sufficient detail for robust causality determination [2] [4] [7]. Reviews also stress frequent label‑content discrepancies, adulteration, and dose variability in herbal supplements, meaning product testing and manufacturing heterogeneity can contribute to risk and complicate attribution [13].
6. Caveats, alternative viewpoints and practical takeaways
While concentrated GTE supplements have a reproducible but rare association with clinically significant liver injury, traditional green tea beverage consumption is not implicated at typical dietary levels and most users experience no harm; experts emphasize that risk appears dose‑related and idiosyncratic, influenced by genetic susceptibility, fasting, and duration of use, and that mixed‑ingredient “fat burners” create attribution challenges [1] [12] [11]. Limitations in the evidence include under‑reporting, heterogeneous case quality, and confounding by co‑consumed products—therefore conclusions about absolute incidence are imprecise even as the signal for caution around high‑dose, concentrated GTE in weight‑loss supplements is consistent across multiple reviews and regulatory notices [1] [2] [4].