why are there variations of injection times for b12 Not All Injections Equal: What to Know Before Your Appointment – Timeless Wellbeing B12 Shots: Vitamin B12 Injections
Description
It is also used with caution in breastfeeding women and children & adolescents (aged below 18 years)

We performed an extensive review of the literature to provide practical recommendations on when to suspect and how to diagnose and manage excipient hypersensitivity
Common Side Effects Mild pain or redness at the injection site Temporary dizziness Serious Side Effects Allergic reaction (rare) Swelling or breathing difficulty Serious reactions are uncommon, but you should seek medical help if symptoms worsen
Vitamin B12 helps in healthy regulation of the nervous system, reducing depression, stress and brain shrinkage

& Lee, R