Having balanced levels of vitamin B12 helps you feel happier and healthier
Evidence boundary The largest Phase 2b trial used oral dosing for 24 weeks and did not show statistically significant weight loss versus placebo
Other side effects that can occur include: Excessive sweat production Rapid weight gain Pain when breathing Shortness of breath when lying down Anxiety Increased or irregular heart rate Numbness, tingling or muscular weakness Increased thirst Urinary frequency B12 injections can also cause allergy symptoms immediately after administration, like difficulty breathing, a swollen throat, mouth, or swelling of the mouth, tongue or face

deficiency (more common in those following plant-based diets or with malabsorption) can cause palpitations and fatigue, primarily through anaemia [2] [3] Vitamin D some observational studies have suggested a possible association between low vitamin D and cardiac arrhythmias, though the evidence remains preliminary and no causal link has been established [20] [21] Calcium severe hypocalcaemia can affect cardiac muscle function, though this is rarely caused by dietary restriction alone and usually reflects an underlying medical condition If you are concerned about nutritional deficiencies, your GP can arrange appropriate blood tests, which may include a full blood count (FBC), ferritin, vitamin B12 and folate, and urea and electrolytes (U&Es), with magnesium and calcium checked if clinically indicated
The shots are usually given in the arm and are released into the body over one to three months