Struggling with B12 injection frequency? Here's what you need to know If you have Pernicious Anaemia (PA) or B12 deficiency due to autoimmune gastritis, NHS guidance is clear: You should B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Pernicious Anemia: Definition, Symptoms, Causes & Treatment Medinaz Vitamin B12 Deficiency: Vitamin B12 deficiency is a nutritional or absorption related disorder leading to impaired DNA synthesis and neurologic dysfunction, commonly presenting with megaloblastic anemia and neuropsychiatric symptoms Vitamin B12 deficiency and cognitive impairment: A comprehensive review of neurological impact ScienceDirect