Itching or swelling around the injection area
Subcutaneous injections target the fatty tissue layer between the skin and the muscle
Naunyn Schmiedeb
In formulation and product-reference settings, blends of this type are discussed for their relationship to metabolic pathways, nutrient composition, and cofactor-supported biochemical systems
Brain function: Brain fog, memory problems, cognitive impairment, insomnia, headaches (especially migraine), behavioural changes, learning problems, nominal aphasia Mood: Mood swings, irritability, depression, anxiety, hallucinations, delusions, psychosis Sensory: Peripheral paraesthesia (pins and needles), numbness, neuropathic pains, poor balance, reduced vibration sense or proprioception (joint position sense), tinnitus, ataxia, taste impairment, sometimes myelopathy Constitutional: Fatigue, anaemia (either macrocytic, or normocytic when also iron deficient or associated with thalassaemia minor), other cytopenia, abdominal complaints, malabsorption, failure to thrive, weight loss, diarrhoea, hyperpigmentation, glossitis, (aphthous) stomatitis, infertility, urinary tract infections Motor: Muscle weakness, altered reflexes (increased in degeneration of the spinal cord, reduced when peripheral neuropathy dominates), spasticity, seizures, cardiomyopathy Autonomic: Urinary and/or faecal incontinence, postural hypotension or dizziness, erectile dysfunction Diagnosing B 12 deficiency can be challenging because no single specific measurement exists to reliably diagnose or refute the presence of B 12 deficiency 11 12 26 27 (box 2)
Serious adverse reactions are extremely rare
