Life SciencesNutritional SciencesPharmacologyBioavailabilityHuman NutritionMicronutrient NutritionMicronutrient AbsorptionUrinary ExcretionVitamin B12 PhysiologyVitamin BiochemistryVitamin MetabolismVitamin PhysiologyBioavailability Of Vitamin B12Intramuscular Medication AdministrationVitamin B12 (Cobalamin)Vitamin B12 Metabolism