Some patients notice an almost immediate boost in energy and mood
If you have known allergies or sensitivities, inform your healthcare provider before starting any treatment
Benefits of subcutaneous administration include: Easier for patients to give themselves injections Less risk of muscle irritation Potential for slower absorption, depending on the injection site Intravenous (IV) Usage in Clinical Settings Intravenous Vitamin B12 is usually used for severe deficiency cases or when quick correction is needed

Common signs and symptoms include Skin reactions, including hives and itching and flushed or pale skin Wheezing and breathing trouble Slurred speech Shock Nausea, vomiting or diarrhea Low blood pressure (hypotension) Facial swelling Dizziness or fainting Difficulty swallowing Constriction of airways and a swollen tongue or throat Anxiety and confusion Abdominal pain A weak and rapid pulse There are not many known risk factors for anaphylaxis, but certain things may increase the potential risk associated with the condition and these include previous anaphylaxis, allergies or asthma and certain other conditions (like heart disease and an abnormal accumulation of a certain type of white blood cell (mastocytosis)
IM injections allow for slower absorption , giving the vitamin to the blood over time
Development & Approval Process | Drugs