vitamin b12 injection 30ml vial Cyanocobalamin (Vitamin Complex) — Mountainside Medical Veterinarians may prescribe vitamin B12 injections to animals with a deficiency B12 Injections at Home: Step-by-Step
Description
The lead time may vary depending on the order volume and destination

My doctor never mentioned side effects from the b12 injections

Serious side effects are extremely uncommon , especially with intramuscular (IM) and IV administration using clinically appropriate doses

Those are covered at the end of this article