B12 injections may improve symptoms of fatigue in deficient individuals, and more energy naturally makes it easier to stay active, which supports a healthy weight over time
I myself have bad histamine intolerance, and over the past few months it's started seeming more and more likely that I also have some degree of mast cell activation syndrome
B12 injections are most clearly indicated when: A person has confirmed B12 deficiency that requires rapid replacement Theres a known or likely absorption issue Theres a need for ongoing maintenance due to non-dietary causes (for example, autoimmune gastritis) Typical treatment schedules (UK guidance) Treatment schedules can vary depending on symptoms, severity, and cause
Malinda KM, Sidhu GS, Mani H, et al
The dose simply not working An incorrect dose, or one that mostly landed in fat, may mean your symptoms do not improve as expected