Phenolic acids, a class of plant-derived polyphenols including compounds such as ferulic acid, caffeic acid, and gallic acid, have been studied for their potential benefits to the skin. The scientific rationale for their use in supporting skin health primarily centers on their antioxidant, anti-inflammatory, and photoprotective properties. Research indicates that phenolic acids can neutralize free radicals generated by ultraviolet (UV) exposure and environmental pollutants, thereby reducing oxidative stress—a key contributor to skin aging and damage (source). Additionally, some phenolic acids exhibit anti-inflammatory effects that may help soothe irritated skin or reduce redness.

Preclinical studies and a limited number of clinical trials have shown that topical application or oral consumption of phenolic acid-rich extracts can improve skin barrier function, reduce signs of photoaging, and protect against UV-induced erythema. For example, ferulic acid is commonly included in commercial skincare formulations for its ability to stabilize vitamins C and E and enhance their photoprotective effects. However, while the body of evidence is growing, most of the data comes from laboratory and animal studies, with relatively fewer large-scale human trials confirming efficacy for specific skin conditions.

In summary, the use of phenolic acids to support skin health is scientifically plausible and supported by moderate evidence, primarily from preclinical research and some human studies, justifying a mid-range evidence rating.