why do i feel worse after my b12 injection Are Vitamin B12 Shots Right for You? Why Do I Feel Worse
Description
Research trials often employ a once-weekly subcutaneous micro-dosing approach, typically around 0.1 mL, to maintain consistent exposure levels in peptide models

Endocrinology 134 , 24042409 (1994)

each 10 mg vial provides 24 days of material

Your haematologist will advise on how long you need to keep taking the injections