Apigenin is a flavonoid shown to influence weight, inflammation, and insulin resistance by altering the gut microbiota. Apigenin supplementation was shown to restore the richness and diversity of the gut microbiota. Apigenin inhibits CD38, a key enzyme involved in the age-related decline of NAD+. CD38 is responsible for NAD decline and mitochondrial dysfunction. CD38 also metabolizes the NAD precursor NMN and modulates the response to NAD-replacement therapy.