vitamin b12 im injection for Cyanocobalamin 1,000 mcg, 25/Box (Rx) — Mountainside Medical Vitamin B12 Cyanocobalamin injection 1000
Description
Vitamin B12 Injection Pure methylcobalamin IM

Vitamin B12 shots can help boost energy levels, improve mood, support brain function, enhance metabolism, and promote healthy red blood cell production
Curr Opin Gastroenterol 2012;28:1518

And its one where the chemistry gives a clearer answer than most compounds in this space

A challenge with this vitamin is that some people can eat plenty of B12-rich foods but still can't absorb it properly