This is determined by the presence of a molecule called the intrinsic factor that is essential for the absorption of B12 into your system
Its a protein that, when injected in tiny, targeted amounts, stops your nerves from talking to your muscles
These extremely rare side effects include: Reactive thrombocytosis during the first week of use in megaloblastic anaemia Hypersensitivity reactions including: rash, itching, exanthema, antibodies to HYDR0XOCOBALAMIN-transcobalamin II Anaphylaxis Hypokalaemia Headache, paraesthesia, tremor Irregular heartbeat (arrhythmias secondary to hypokalaemia) Nausea Vomiting Diarrhoea Fever, chills, hot flushes, dizziness, malaise, pain and / or swelling at the injection site Acne Abnormal colouration of the urine (chromaturia) What should you not do after a B12 shot
The timeline varies based on individual factors including starting point, dosing, diet, and exercise habits