Adverse reactions reported following methylcobalamin administration include headache, infection, nausea/vomiting, paresthesias, and rhinitis
An injection bypasses this entire process, delivering the vitamin directly into your system for 100% absorption
Concurrent iron-deficiency anemia and folic acid deficiency may result in a blunted or impeded response to methylcobalamin therapy
If you see persistent pain, redness, or itching at the site of the injection, mild diarrhea, swelling sensation in your body, or temporary itching in your skin, contact your doctor immediately
Oral supplements have also been shown to be effective at treating vitamin B12 deficiency