feeling tired after vitamin b12 injection I Feel All the Time. Do I Need a Shot?: Shawn Veiseh, M.D.: Family Medicine still feeling tired after b12

Research remains in early stages with no human clinical trials currently approved

No antibody formation When the immune system recognizes a foreign protein and produces antibodies against it, this can reduce the compound effectiveness over time and potentially cause allergic reactions

Assess your risk tolerance

We use cyanocobalamin by default, the form of B12 with the longest clinical history, the most extensive research support, and the consistent potency needed for repeated treatments

Medical Coding for Injections in 2026: CPT Codes, Administration Routes, Documentation Guidelines, and CPC Exam Tips By Janine Mothershed CPC, CPC-I Key Takeaways Injection administration coding depends on the route of administration , the drug or substance administered , and the medical necessity documented in the record