thigh injection site b12 Vitamin C and Techniques B12 Injections for Energy: Benefits
Description
Can B12 Shots Help with Weight Loss

Sanchez, CMA/Lab Tech Allen K

eNAMPT may also allow extracellular conversion of NAM to NMN, as eNAMPT is catalytically active 43

Older people with gastrointestinal problems are more susceptible to B12 deficiency, due to increased issues with absorption
A different pattern of crying

So normal people don't really "store" it but most is not lost