Since B12 injections are regarded as medical procedures, they usually fall under Part B rather than Part D
Principal Investigator on A Double-Blind, Randomized, Parallel-Group Study with Quetiapine Extended Release as Comparator to Evaluate the Efficacy and Safety of Seltorexant 20 mg as Adjunctive Therapy to Antidepressants in Adult and Elderly Patients with Major Depressive Disorder with Insomnia Symptoms Who Have Responded Inadequately to Antidepressant Therapy. (Janssen)
by Chris Kresser [ Wu Y, Kajdacsy-Balla A, Strawn E, Basir Z, Halverson G, Jailwala P, Wang Y, Wang X, Ghosh S, Guo SW
2019, Chu et al
What does B12 do for your body
Glycine is a primary component of both collagen and glutathione