Phytoestrogens are naturally occurring bioactive compounds that resemble endogenous estrogens, especially estradiol, in both structure and function. These compounds are commonly present in dietary sources such as flaxseeds, soybeans, legumes, and whole-grain products. They have been extensively studied for their ability to influence endocrine system function. As selective estrogen receptor modulators (SERMs), phytoestrogens show dual activity, acting either as estrogenic or anti-estrogenic depending on the target tissue, receptor binding affinity, and individual hormonal profiles. Their potential health benefits include alleviating menopausal symptoms, enhancing bone health, providing cardiovascular protection, and supporting metabolic regulation. Specific bioactive compounds, such as lignans, isoflavones, coumestans, and stilbenes, have demonstrated potential in reducing the risks of osteoporosis, cardiovascular disease, and insulin resistance. However, despite these benefits, concerns about their endocrine-disrupting effects exist. Excessive intake or exposure during sensitive developmental periods may disrupt reproductive systems, alter pubertal timing, suppress thyroid function, or increase the risk of hormone-sensitive cancers. Individual differences in gut microbiome composition significantly influence phytoestrogen metabolism, resulting in substantial variation in biological responses among individuals. This review examines the primary dietary sources of phytoestrogens, elucidates their underlying mechanisms of action, and evaluates both their health benefits, potential adverse effects. This analysis identifies critical knowledge gaps and emphasises the importance of continued research to ensure safety and optimise phytoestrogen applications in nutritional interventions and functional food development