The NHS gives hydroxocobalamin as an intramuscular injection, but published evidence shows the subcutaneous route is a recognised and similarly effective alternative
The abdomen provides consistent absorption, easy access for self-administration, and adequate fatty tissue in most individuals
Headache: Some individuals may experience headaches after receiving a vitamin B12 injection
In rare situations, B12 shots itching rash anaphylaxis, a life threatening condition that can cause a fast heartbeat and difficulty breathing Other side effects that can occur include: shortness of breath, fast weight gain, and swelling congestive heart failure, the inability of the heart to adequately pump blood pulmonary edema, the buildup of fluid in the lungs peripheral vascular thrombosis, the obstruction of a vein with a blood clot hypokalemia, low potassium levels that can cause irregular heartbeats and muscle weakness fever tingling, numbness, and joint pain swollen tongue polycythemia, an increase in the red blood cell mass Additionally, B12 B12 shots are not necessary for weight loss