Ligustrum fruit (Ligustrum lucidum), also known as "Nu Zhen Zi" in Traditional Chinese Medicine (TCM), has a long history of use for supporting kidney health. In TCM, Ligustrum fruit is categorized as a tonic herb, specifically used to "nourish and tonify the Liver and Kidneys" and is often included in formulas intended to address symptoms such as lower back pain, tinnitus, dizziness, and premature graying of hair—symptoms interpreted as signs of "Kidney deficiency" in TCM theory.

Despite its widespread traditional use, scientific evidence to directly support Ligustrum fruit as a kidney tonic in the Western biomedical sense is limited. Some laboratory and animal studies have investigated the fruit for its antioxidant, anti-inflammatory, and immunomodulatory properties. For example, research has identified various bioactive compounds (such as oleanolic acid and ligustroside) that may have protective effects on organs, including the kidneys, in animal models of oxidative stress or nephrotoxicity. However, these findings are preliminary and have not been confirmed in robust human clinical trials. There is also a lack of direct scientific validation correlating Ligustrum’s traditional use for "Kidney" support in TCM with its effect on kidney function as defined by modern medicine.

In summary, the use of Ligustrum fruit for kidney support is primarily justified by traditional herbal practices, with some suggestive but limited preclinical scientific data. High-quality human clinical studies are needed to substantiate these traditional claims.