correct size needle for b12 injection in butt Ultimate Buttock Guide How to Give a B12
Description
Having an injection means that the vitamin is delivered straight into the blood stream
Immunomodulation by vitamin B12: augmentation of CD8+ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment

Also this same situation is happening when pt comes in for ESWL (50590) w/ 90 day global, & the same injection is administered as above
Nature 508, 258262

[3] Patients with deficiencies often experience fatigue, cognitive or nerve impairments, and slow recovery
