2nd b12 injection B-12 (Cyanocobalamin) Shot Therapy Feeling worse after B12 Injection:

It might take some time for your energy levels to fully recover

Another RCT found a decrease in homocysteine with 1000 g hydroxo-B12 monthly for 3 months by 2 mol/l, whilst the control group had a 2 mol/l increase, although the difference was not statistically significant

To confirm that your current symptoms are caused by a recent infection , doctors rely on a special test: the four-fold rise in paired IgG

Discontinue two weeks before surgery or if you experience rapid heartbeat, dizziness, severe headache, or shortness of breath

After the deficiency is fixed, injections might be needed only once a month

Switzerland Federal Office of Public Health