why have vitamin b12 injections 10 Reasons to Look Into Sublingual B12 vs. B12 Injections:

Common signs include persistent fatigue (even after a full nights sleep), brain fog, mood swings or irritability, numbness or tingling in the hands or feet, and a weakened immune system

Cognitive Function Brain Health : Vitamin B12 deficiency has been associated with memory loss, especially in older adults

Those with B-12 deficiencies may experience brain fog, memory problems, or mood disturbances, which can be mitigated with regular injections

a combination of 1 mM IBMX, 1 M dexamethasone, and 10 g/ml of insulin in media were added to fully confluent 3T3-L1 fibroblasts for three days (days 0-3) to initiate differentiation