Estradiol, also known as 17β-Estradiol or E2, is an endogenous steroid hormone primarily produced in the ovaries, with additional synthesis occurring in the brain and adipose tissue. It belongs to the class of estrogens, which are key sex hormones involved in the regulation of the female reproductive system and secondary sexual characteristics. Estradiol is also available in synthetic forms, such as estradiol valerate, for therapeutic use. Researchers have extensively studied estradiol for its role in various physiological processes and its potential therapeutic applications. It plays a critical role in neuroplasticity, influencing synaptic rearrangements in brain regions associated with learning and memory, such as the cortex and hippocampus. Estradiol is also implicated in the modulation of mitochondrial function, particularly in the context of acute lung injury and inflammation resolution. The hormone's mechanism of action involves binding to estrogen receptors, primarily ERα and ERβ, and activating genomic and non-genomic pathways. These pathways include the p38 MAPK pathway, which is involved in matrix mineralization and may have therapeutic implications for conditions like osteoporosis. Estradiol's pharmacokinetic properties vary depending on the form and route of administration. Endogenously, it has a circulating half-life of approximately 70 minutes. When administered orally, its bioavailability is limited due to first-pass metabolism, whereas transdermal and injectable forms offer more stable pharmacokinetic profiles. Clinically, estradiol is used in hormone replacement therapy, particularly for menopausal symptoms, and is regulated as a prescription medication in many countries. Researchers continue to explore its broader therapeutic potential in various medical conditions, including neurodegenerative diseases and inflammatory disorders.