Vitamin B12 Injection

About the Vitamin B12 Injection

Vitamin B12 (cobalamin) is an essential water-soluble vitamin required for red blood cell formation, neurological function, and DNA synthesis. B12 is found almost exclusively in animal-derived foods; deficiency is therefore common in those following vegan or vegetarian diets, as well as in individuals whose absorption is impaired by autoimmune conditions, gastrointestinal disease, or certain medications.

Intramuscular B12 injections (typically hydroxocobalamin) bypass the gastrointestinal tract entirely, delivering the vitamin directly into muscle tissue for absorption into the bloodstream. This makes them far more effective than oral supplements for individuals with absorption difficulties — including those with pernicious anaemia, where intrinsic factor required for B12 absorption is absent. Many patients notice improvements in energy levels, cognitive function, and mood within days of their first injection.

Who should have this vaccination?

• Individuals with confirmed or suspected B12 deficiency presenting with fatigue, brain fog, memory difficulties, tingling or numbness in the hands and feet, low mood, or breathlessness
• Those following a vegan or vegetarian diet, particularly if unable to maintain adequate B12 levels through oral supplementation
• Individuals with pernicious anaemia — an autoimmune condition preventing production of intrinsic factor and therefore absorption of dietary B12
• Patients who have undergone gastric bypass, bowel resection, or other gastrointestinal surgery affecting B12 absorption
• Those taking metformin (for type 2 diabetes) or long-term proton pump inhibitors, which can deplete B12 levels over time
• Older adults, in whom B12 absorption naturally declines with age due to reduced gastric acid production
• Individuals with Crohn's disease, coeliac disease, or other conditions causing malabsorption

Vaccination schedule

The frequency of B12 injections depends on the underlying cause of deficiency. For pernicious anaemia and conditions causing malabsorption, hydroxocobalamin is typically given every three months on an ongoing basis following an initial loading course. For dietary deficiency, a loading course may be recommended initially, with maintenance injections as required based on B12 blood levels. A blood test prior to beginning injections is strongly recommended to confirm deficiency and establish a baseline — this can be arranged at The Vesey at the same appointment.