Injection of B12 is safe, simple, and cheaper
Delays in diagnosis and subsequent initiation in treatment of pernicious anaemia have been shown to increase the risk of irreversible neurological damage involving both the central and peripheral nervous system, resulting in permanent symptoms, such as peripheral neuropathy, cognitive impairment and damage to the spinal cord (known as subacute combined degeneration of the spinal cord)[9,16]
a larger Intramuscular (in the muscle) 25 gauge 1 inch needle for maximum intramuscular benefit, a shorter 25 gauge 5/8 inch, and a smaller Deep Subcutaneous (under skin) 29 gauge 1/2 inch needle
Sources Emedicine, Vitamin Toxicity, Getting Too Much of Vitamins and Minerals, Linus Pauling Institute, Micronutrient Information Center, Pantothenic Acid, Linus Pauling Institute, Micronutrient Information Center, Biotin, MedlinePlus, Niacin, National Institutes of Health, Riboflavin: Fact Sheet for Health Professionals, Further Reading All Vitamin B Content Vitamin B Function in the Body Vitamin B Deficiency Good Sources of Vitamin B Types of Vitamin B Last Updated: Feb 27, 2019 Written by Dr