A healthcare provider adjusts the schedule based on follow-up blood work and symptom response
Allergic reactions A small group of people might react to the preservative in the injection
Vitamin B12 deficiency can also cause symptoms that affect the brain and nervous system (neurologic symptoms), including: Numbness Muscle weakness Mental health problems, ranging from mild depression or anxiety to confusion and dementia Balance and coordination issues Needles and pins Incontinence What is the best form of vitamin B12 to take
PLoS ONE 8 , e74083 (2013)
You should contact your GP or NHS 111 if you experience: Persistent diarrhoea lasting more than 7 days in otherwise healthy adults Blood or mucus in stools , which may indicate inflammatory bowel disease or infection Severe abdominal pain or cramping that is worsening or different from previous digestive symptoms Unexplained weight loss alongside bowel changes Signs of allergic reaction , including rash, itching, swelling, or difficulty breathing (call 999 or go to A&E for severe reactions) Neurological symptoms such as numbness, tingling, balance problems, or memory difficulties, which may indicate B12 deficiency is not being adequately treated Seek help sooner if you have red flag symptoms, are pregnant, immunosuppressed, elderly, or have significant underlying health conditions