Polyphenols are a diverse group of naturally occurring compounds found abundantly in fruits, vegetables, tea, coffee, wine, and other plant-based foods. Their use to support the hepatic (liver) system is primarily justified by a growing body of scientific evidence. Studies have demonstrated that various polyphenols, such as flavonoids (e.g., quercetin, catechins), phenolic acids (e.g., caffeic acid), and stilbenes (e.g., resveratrol), exert hepatoprotective effects. These effects are mainly attributed to their antioxidant, anti-inflammatory, and anti-fibrotic properties.

Research in both animal models and humans indicates that polyphenols can help mitigate liver damage caused by toxins, high-fat diets, and alcohol. For example, silymarin (from milk thistle), curcumin (from turmeric), and green tea catechins have been shown to reduce oxidative stress, inhibit lipid peroxidation, and modulate inflammatory pathways in the liver. A number of clinical trials have reported improvements in liver enzyme levels and histological markers in patients with non-alcoholic fatty liver disease (NAFLD) and other hepatic conditions after polyphenol supplementation. However, while the evidence is promising, more large-scale and long-term human studies are needed to fully establish efficacy and optimal dosing.

Overall, there is substantial scientific support for the use of various polyphenols in supporting liver health, though recommendations should be individualized and made with consideration of the existing evidence.