Polyphenols are a diverse group of naturally occurring compounds found in plants, including flavonoids, phenolic acids, and tannins. There is a growing body of scientific evidence suggesting that polyphenols can support the hepatic (liver) system. Numerous in vitro and animal studies have demonstrated that polyphenols possess antioxidant and anti-inflammatory properties, which may help protect liver cells from oxidative stress and inflammation—both key contributors to liver injury and disease. Common sources of polyphenols, such as green tea catechins, resveratrol from grapes, and curcumin from turmeric, have been shown in preclinical studies to attenuate liver damage, reduce lipid accumulation, and improve markers of liver function.

Human clinical evidence is more limited but promising. Some studies have reported beneficial effects of polyphenol-rich foods or extracts on markers of liver health, particularly in individuals with non-alcoholic fatty liver disease (NAFLD). For example, supplementation with green tea extract has been associated with reduced liver enzyme levels and improved lipid profiles. However, these studies are often small and of short duration, and results are not always consistent.

While there is enough scientific rationale and some supportive human data, more well-designed clinical trials are needed to make definitive recommendations. Overall, polyphenols are considered a promising adjunct for hepatic support, primarily due to their antioxidant and anti-inflammatory effects, but the current evidence base would be considered moderate.