Some protocols call for B12 injections every other day for two weeks initially, especially for more significant deficiencies, while monthly B12 shots are often sufficient for chronic, stable deficiencies once levels normalize
Hydroxocobalamin 1mg intramuscular injections reactivate metabolic pathways after chronic deficiency, potentially causing temporary symptoms during adjustment Common side effects include injection site pain, headaches, and nausea, typically resolving within 2472 hours Rapid red blood cell production may increase demand for folate and iron, occasionally creating relative deficiencies in these co-factors Serious reactions requiring urgent assessment include difficulty breathing, chest pain, severe weakness, or progressive neurological symptoms Recovery follows a predictable pattern: blood cell improvement within 35 days, haemoglobin normalisation over 12 months, neurological recovery potentially taking several months Table of Contents Why Do I Feel Worse After My B12 Injection
Instead, most people may only experience chronic fatigue or frequent headaches from B12 deficiency
Follow-up labs usually confirm resolution within a few months, though patients with recurring symptoms may eventually switch to methylcobalamin for its additional cellular benefits
