Lycium, commonly known as goji berry or Lycium barbarum, has been traditionally used in Chinese medicine, but its support for mitigating free radical damage is primarily justified by scientific studies. The berries are rich in bioactive compounds, including polysaccharides, carotenoids (notably zeaxanthin), flavonoids, and phenolic acids, all of which have demonstrated antioxidant properties in laboratory and animal studies. These compounds help neutralize free radicals, thereby reducing oxidative stress, which is implicated in cellular aging and the pathogenesis of various diseases.

Several in vitro and in vivo studies have shown that Lycium extracts can increase antioxidant activity and reduce markers of oxidative damage. For instance, research published in journals such as "Oxidative Medicine and Cellular Longevity" and "Food & Function" has documented that Lycium barbarum polysaccharides (LBPs) boost levels of endogenous antioxidants like superoxide dismutase (SOD) and glutathione peroxidase in animal models. Some small human studies have also reported increased antioxidant capacity in plasma after goji berry consumption, although the sample sizes are limited and more robust clinical trials are needed.

Overall, the scientific evidence supporting the use of Lycium for free radical damage is moderate. While laboratory and animal studies are promising and some early human data exist, large-scale, well-controlled clinical trials are lacking. Thus, the evidence rating is 3 out of 5.