The speed at which a Vitamin B12 shot works can vary depending on several factors, including the individuals level of deficiency, overall health, and the presence of any underlying medical conditions
Examples of these health conditions include those with a lack of stomach acid, those who have undergone bariatric surgery, anemia caused by the inability to absorb the vitamin, other autoimmune digestive diseases, as well as several medications
Better Cardiovascular Health May reduce levels of homocysteine, an amino acid linked to heart disease when elevated
National Library of Medicine: Indeed, DNA synthesis is impaired by low vitamin B12, which hampers the activation of folate and, as a result, decreases normal red blood cell production, impairing oxygen delivery [62] WebMD indicates, if you have vitamin B12 deficiency, you could become anemic