By 1926, Minot and Murphy reported clinical and hematological improvement in 45 patients with pernicious anemia treated with a dietary regimen that incorporated large quantities of liver (Minot and Murphy 1926
Anecdotal reports of subcutaneous use exist, but no formal stability, bioavailability, or safety data supports this route
According to various studies, up to 85 percent of patients with vitamin B12 deficiency experience at least one neurological symptom
Higher-Caution Situations Extra medical supervision is important if you: have a history of reactions to injectable vitamins/cobalamins have significant kidney or liver disease are pregnant or breastfeeding are offered a compounded MIC B12 product without clear labeling of ingredients, concentrations, and compounding source The FDAs overview of compounding helps explain why quality can vary (see Compounding and the FDA: Questions and Answers )
They work best and provide the most noticeable results when paired with healthy, sustainable habits