Flavanones are a subclass of flavonoids, naturally occurring polyphenolic compounds found abundantly in citrus fruits such as oranges, lemons, and grapefruits. Their use to support or counteract free radical damage is primarily justified by scientific research. Free radical damage, or oxidative stress, is implicated in aging and various chronic diseases. Flavanones, particularly hesperidin, naringin, and eriocitrin, have demonstrated antioxidant properties in vitro and in animal studies. They act by scavenging reactive oxygen species (ROS), upregulating endogenous antioxidant enzymes (such as superoxide dismutase and glutathione peroxidase), and inhibiting lipid peroxidation.

Several laboratory and animal studies have shown that flavanones can reduce oxidative stress markers and improve antioxidant defenses. Human studies are somewhat more limited, but available research indicates that regular consumption of citrus flavanones increases antioxidant capacity in plasma and reduces markers of oxidative damage. For example, a few small clinical trials have found that hesperidin supplementation can reduce biomarkers of oxidative stress in humans, although results are not entirely consistent and sometimes limited by sample size or study duration.

Overall, the evidence supporting flavanones for free radical damage is moderate. There is a plausible mechanism, consistent preclinical data, and some supportive human studies, but more large-scale and long-term clinical trials are needed to confirm efficacy and establish optimal dosing.