Brain-Derived Neurotrophic Factor (BDNF), also known as Abrineurin, is an endogenous protein belonging to the neurotrophin family of growth factors. It is primarily produced in the central nervous system, particularly in the brain regions such as the hippocampus, cortex, and basal forebrain. BDNF is a member of the chemical class of proteins and is encoded by the BDNF gene. It plays a crucial role in the development and maintenance of neuronal networks. Researchers have extensively studied BDNF for its involvement in neuroplasticity, which is the brain's ability to reorganize itself by forming new neural connections. BDNF is vital for long-term memory formation and is implicated in various neurological and psychiatric disorders, including depression, schizophrenia, and Alzheimer's disease. It is also a focus of research in neurodegenerative diseases and recovery from brain injuries. The mechanism of action of BDNF involves binding to its high-affinity receptor, TrkB (tropomyosin receptor kinase B), and the low-affinity receptor, p75NTR. Upon binding, it activates several intracellular signaling pathways, including the MAPK/ERK, PI3K/Akt, and PLCγ pathways, leading to neuronal survival, growth, and differentiation. BDNF's pharmacokinetic properties are not well-defined due to its endogenous nature. However, researchers have observed that it has a short circulating half-life and is rapidly metabolized. Its bioavailability is limited when administered exogenously due to its large molecular size and inability to cross the blood-brain barrier effectively. Clinically, BDNF is not directly used as a therapeutic agent due to these pharmacokinetic challenges. However, it is a target for drug development aimed at modulating its levels or mimicking its effects. Currently, there are no regulatory approvals for BDNF as a direct therapeutic agent, but it remains a significant focus of research for potential therapeutic strategies in neurological and psychiatric conditions.