Dihydrodaidzein is a hydrogenated product of the conversion of daidzein, the main component of soy isoflavones, under the metabolic action of intestinal microorganisms. Being the intermediary metabolite of soy isoflavones, dihydrodaidzein is widely acknowledged to exhibit heightened biological activity. During intestinal transformation in vivo, dihydrodaidzein can subsequently undergo further hydroxylation to form the more active equol. Compared with its metabolic precursor, daidzein, dihydrodaidzein exhibits higher activity and broader biological effects, due to which it has gradually attracted the attention of many scientists in recent years. It has been found to have superior pharmacological activities due to its antioxidant properties, potential prevention of cardiovascular disease andosteoporosis, and estrogen-like activity. However, there is currently a scarcity of literature providing a systematic and comprehensive overview of DHD. Considering the high biological activity and potential market value of DHD, this article reviews advancements in DHD research, encompassing its sources, biosynthetic pathways, physicochemical properties, metabolism, bioavailability, biological activity, and pharmacology. Emphasis is placed on elucidating the biosynthesis biotransformation, biological activity, and pharmacology of DHD, aiming to maximize its intrinsic value and contribute to its application in the realms of medicine and clinical practice. Dihydrodaidzein suffers from low water solubility, instability, and low oral bioavailability, so emerging nanocarrier technologies can be explored to encapsulate dihydrodaidzein to enhance its solubility, cellular uptake, targeted delivery, and functional efficacy. Future endeavors should prioritize additional research to assess its bioavailability, potentially paving the way for its inclusion in future nutritional supplements.