NICE guidelines recommend hydroxocobalamin 1 mg intramuscularly three times weekly for 2 weeks (without neurological involvement) or on alternate days until no further improvement (with neurological symptoms)
Wolf E, Hoeflich A, Lahm H
You may need B12 injections if you: Have been diagnosed with pernicious anemia Have gastrointestinal issues (e.g., Crohns disease, celiac disease, or after bariatric surgery) Follow a strict vegan or vegetarian diet without adequate supplementation Are over the age of 50, as absorption decreases with age Take certain medications that interfere with B12 absorption Have chronic fatigue, memory issues, or nerve problems due to B12 deficiency
Those most at risk include vegans and vegetarians, people with digestive conditions such as Crohn's disease, coeliac disease or IBS, those taking long-term metformin or proton pump inhibitors, older adults whose ability to absorb B12 through the gut declines naturally with age, those with pernicious anaemia, and anyone with a history of chronic alcohol use