Key B12 Injection contains Methylcobalamin 1500 mcg, a biologically active form of vitamin B12 essential for neurological function and hematopoiesis. This injectable formulation is indicated for the treatment and prevention of vitamin B12 deficiency, which may result from pernicious anemia, malabsorption syndromes, or dietary insufficiency. Methylcobalamin plays a crucial role in DNA synthesis, red blood cell formation, and maintenance of the myelin sheath surrounding nerves, thereby supporting nerve regeneration and reducing neurological symptoms associated with deficiency. Key B12 Injection is administered intramuscularly or subcutaneously, allowing rapid absorption and bioavailability compared to oral preparations, making it suitable for patients with impaired gastrointestinal absorption. The typical dosage regimen varies based on the severity of deficiency and clinical response, with healthcare providers adjusting treatment accordingly. Adverse effects are generally rare but may include mild injection site reactions or hypersensitivity. Caution is advised in patients with known hypersensitivity to cobalamin or any component of the formulation. Regular monitoring of hematologic parameters and clinical symptoms is recommended to assess therapeutic efficacy. Key B12 Injection is a vital therapeutic option in managing vitamin B12 deficiency and associated neurological and hematological disorders.