Your body converts it into methylcobalamin, which is the active form
Methionine helps break down fats, Choline aids in their transportation and metabolism, while Inositol ensures the efficient use of these fats for energy
Cochrane Database of Systematic Reviews
[1] [6] Severe deficiencies may include symptoms of reduced heart function, suppression of bone marrow, as well as more various severe neurological symptoms possibly including sensory loss, abnormal balance and reflexes, memory and consciousness impairment, smell and taste problems, depression, irritability, confusion, and psychosis
Put the used needle in a puncture-proof disposal container