severe pain after b12 injection Are Vitamin Shots Right for You? How Long Does a B12

Professor and Chair, Department of Nutritional Sciences Rutgers, The State University of New Jersey Copyright 2000-2026 Linus Pauling Institute Figure Alternative Text Figure 1

Studies show Methylcobalamin is the specific form of B12 needed for nervous system health

Gore M, Brandenburg NA, Dukes E, Hoffman DL, Tai KS, Stacey B

For a detailed head-to-head analysis including dosing charts , efficacy data, and practical recommendations, see our dedicated comparison guides

You may not get enough B12 in your diet if you are: Vegan Vegetarian Over 50 Living with digestive conditions that affect nutrient absorption, such as IBS, celiac, or Crohns disease Taking certain medications like metformin or proton pump inhibitors (PPIs) What are the symptoms of B12 deficiency

Just half of a cooked salmon fillet (6 ounces) contains more than 200% of the daily value of vitamin B12