B12 supplementation is also forbidden in cases of lupus, Crohn's disease, celiac disease, graves' disease, some cancers, pernicious anemia, and some infections. Some prescription drugs, including antacids and some treatments for type 2 diabetes, can make the body's B12 levels less adequate.
How are you feeling following a B-12 Injection? receiving an injection The muscle is injected with the medication (known as an intramuscular injection). Wherever the injection was given, you might experience some pain, swelling, or itching. However, this is typically only mild and will pass quickly.