b12 injection pre workout Vitamin as a Pre-Workout MIC B12 from Fitish RX Pre-Shot Variety Pack | Try

Individual differences: The duration of B12 injection benefits can also vary based on individual factors, such as age, genetics, and overall health status

protect from light and moisture

Factors Influencing the Effectiveness of Vitamin B12 Shots Several factors can influence how quickly and effectively a Vitamin B12 shot works: Severity of Deficiency : Individuals with severe Vitamin B12 deficiency may experience a more noticeable and rapid improvement in symptoms compared to those with mild deficiency

You'd need 2 injections of ~25.0 units each

A B12 supplement can also do the trick

But for people with normal B12 levels, injections do not reliably cause targeted fat loss