b12 injection 5ml vial buy Cyanocobalamin Injection, 1000 mcg/mL 1mL Veterinarians may prescribe vitamin B12 injections to animals with a deficiency Vitamin B-12 3000 mcg Injection,
Description
you can use it within 28 days
The spray form and light fruity flavor makes this option very easy to take

That does not mean absolutely nothing happens before then
It has two options: 3-monthly b12 injections or (often against clinician advice) no treatment
