how much b12 is in injection Cyanocobalamin Vitamin 1000 mcg — Mountainside Medical Compounded Methylcobalamin (Vitamin B12) Injection,
Description
2004 Apr;5(4):43640

Daily injections of 1000 mcg (1 mg) of Vitamin B12 are given

So, when your B12 is low, its no wonder you feel drained

True, if the roles were reversed your cat wouldn't do the same for you but that's only because they don't have fingers
