vitamin b12 by intramuscular injection rather than orally Efficacy of different routes of supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta-analysis Oral versus intramuscular administration of
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Bioengineering, 9(8), 365

Double-blind, placebo-controlled study of ranitidine for gastroesophageal reflux symptoms during pregnancy

A B12 shot can help alleviate some of these symptoms

A neutrophil activation signature predicts critical illness and mortality in COVID-19

Unlike most other nutrients, the human body cannot absorb Vitamin D from food but rather absorbs it from the suns ultraviolet (UV) rays through the skin

With that in mind, we could say that B12 supplementation for bariatric patients must be for life
