do b12 injections work better than pills Vitamin vs. Supplements: Which is Right for You? B12 Injections vs Oral Supplements:

The subcutaneous route is used at much smaller doses than oral because a 100 mg injection would require two 50 mg vials and about 6 mL of liquid when each vial is mixed with 3.0 mL BAC water, which is too much for one subcutaneous site

All vitamin B complex supplements tend to interfere with antibiotics' effectiveness, and therefore they should be taken at different times

(National Academy Press) Scalabrino G

Minor side effects can include: A bit of tenderness, puffiness, or pink discoloration right around the puncture A brief warm or flushed sensation Mild headache or nausea Reach out to a medical professional right away if you notice: Redness that keeps spreading, heat, or discharge near the site (possible infection) Hives, facial swelling, or difficulty breathing (possible allergic reaction) Persistent numbness or tingling that spreads beyond the site Fever or chills within 48 hours of injection Safe Needle Disposal and Storage A proper FDA-cleared sharps bin is ideal