how do you administer b12 injections To Self-Inject What happens if you inject

Elinor Huntsman, and Jessie H

If you follow a vegan diet, lack B12-rich food, or suffer from health conditions like B12 deficiency, which happens when a person cannot absorb it properly, then you may experience b12 deficiency

As B12 is essential for the production of red blood cells and proper nervous system function, its deficiency can disrupt these processes and lead to symptoms like gastrointestinal discomfort and poor appetite, which may contribute to unintended weight loss

It should be used with caution in patients with severe, pre-existing mitochondrial disease

Last clinically reviewed: 31 July 2026 Clinical information sources NICE NG239 Vitamin B12 deficiency in over 16s: diagnosis and management NHS Vitamin B12 or folate deficiency anaemia NHS Diagnosis NHS Treatment MHRA Vitamin B12 and cobalt allergy advice This page provides general information about the pharmacy service and does not replace personalised advice from a pharmacist, GP or other healthcare professional

People with known allergies to copper or to any of the amino acids in the peptide sequence should avoid AHK-Cu