After the U.S. Food and Drug Administration (FDA) actions against ephedrine-containing supplements and over-the-counters, including the herbal products, there was a scramble to find effective weight-loss ingredients. Among the array of ingredients touted to encourage fat loss via one mechanism or another was green tea extract (GTE), and its main active ingredient, EGCG (epigallocatechin gallate).
Studies using EGCG combined with caffeine showed statistically significant weight loss, though the numbers paled in comparison to the much more potent ephedrine and caffeine combinations. By itself, EGCG isn’t effective for promoting weight loss. What’s interesting is that an individual seems to be more likely to experience weight-loss benefits if not a habitual high caffeine consumer (drinking plenty of coffee or energy drinks) and is of Asian descent rather than Caucasian. However, the additional loss of a pound or three is a benefit worth the relatively low cost and inconvenience of a few capsules a day to many people. At least, it is as long as there are no associated health risks.
Among the numerous weight-loss drugs and supplements that were pulled because of reported adverse effects (including deaths) in the last decade or so were a number that contained EGCG. Hydroxycut was formulated with a number of ingredients from 2004 to 2009 that included EGCG, hydroxycitric acid and others. Being the clear market leader in this category, it wasn’t surprising that it was under great scrutiny—the number of adverse reports connected to Hydroxycut, and the severity of the cases, became impossible to ignore. A lot of people suffered liver damage, with some in need of a liver transplant, and at least one death was attributed to the product. As Hydroxycut was a multi-ingredient product, it was difficult to link the damage to one agent. However, over time, other (and prior) studies looking at the potential liver toxicity of EGCG were published.
New studies have been emerging that describe mechanisms or conditions involved in potential liver damage, as well as continuing cases of “drug-induced liver injury” occurring in people taking EGCG-containing products. Paradoxically, EGCG is also hepatoprotective (reduces or prevents liver injury) in the presence of certain drugs and metals, so the biochemistry of EGCG stays in a relative infancy. As it stands, there are numerous suggestions supporting the idea that consumption of a great amount of GTE can induce hepatocellular toxicity (liver damage), and that certain common drugs and supplements may exacerbate this. In the presence of different “toxins,” EGCG could actually promote cellular damage at a lower concentration. Of course, the risk of “drug-induced liver injury” from an herbal product isn’t limited to GTE. In fact, a recent study identified at least 65 herbs with suspected hepatotoxicity risk.
Given the low potency of GTE on weight loss, the limited benefit doesn’t seem to be worth the risk. Most population-based studies showing lower BMI, better health or longevity in association with green tea intake relate to its customary consumption as a drink, wherein the exposure to the active components happens slowly and throughout the day. Fast, sharp spikes in EGCG and other components might be “unnatural” in its presentation to the liver cells, leading to strain and signs of damage in the presence of other “toxins.” Given the continuity of adverse event reports, and the dependence on multi-ingredient products for a weight-loss effect, it’s difficult to support the use of GTE for weight loss at this time. The people who do want to use GTE should consider that it seems to have little weight-loss benefit without the support of caffeine, and seems to do little more than caffeine alone. Avoiding products with a variety of ingredients can reduce the risk of “drug” interactions leading to liver toxicity.