S-Dihydrodaidzein is a metabolite of daidzein, a soy isoflavone, produced by gut microbiota. It has gained attention for its potential role in hormone-related health benefits. It exhibits weak estrogenic activity, making it relevant in research on menopausal symptoms and bone health. Studies suggest it may support cardiovascular health by improving endothelial function and reducing oxidative stress. It is also being investigated for its possible involvement in reducing the risk of certain hormone-dependent cancers, such as breast and prostate cancer, due to its ability to modulate estrogen receptors. Additionally, S-dihydrodaidzein may contribute to gut health by influencing microbial balance and metabolic activity in the colon. Its presence in urine and plasma is often used as a biomarker for isoflavone metabolism and gut microbiome activity.