concentration of b12 in injected form Injection Dosage and Frequency: 7 Guidelines for Adults Vitamin B12 | Linus Pauling

Report persistent nausea or vomiting to your healthcare provider, as severe symptoms may require dose adjustment or temporary treatment interruption

if you develop symptoms like hives, difficulty breathing, chest tightness, or severe dizziness after an injection, seek medical attention, as those could indicate an allergic reaction (which is extremely uncommon)

There is also concern about the potential stimulation of pre-existing testicular tumors with HCG treatment

It is possible that the body eventually regenerates new fat tissue and vasculature, especially if the metabolic conditions that drove original fat accumulation persist