how to give subcutaneous b12 injections Optimal Injection Sites for Maximum Absorption and Benefits Best Vitamin B12 Injection Sites:

Another study conducted by the University of California found that B12 supplements improved energy levels and reduced fatigue in individuals with chronic fatigue syndrome

Individual responses vary, but some individuals may experience improvements in energy levels and symptoms within a few days after starting B12 injections.

Symptom Monitoring: Even though serious adverse events did not occur in trials, individual monitoring for headache, gastrointestinal symptoms, or unusual effects allows for early detection of tolerability issues and appropriate management adjustments

however, for a high dose of vitamin b12, an injection may be a better option for you