feeling tired after vitamin b12 injection makes me sleepy How Soon Do You Feel Less a B12 Injection? Vitamin B12 Deficiency: Symptoms, Causes
Description
When it comes down to it, a vitamin B12 shot can significantly impact your energy levels if you are B12 deficient
Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes

Having adequate B12 levels protects you from a type of anemia called megaloblastic anemia that can cause fatigue and brain fog
Additionally, a subcutaneous injection uses a shorter needle because it does not need to go deep into the tissues

B12 helps keep nerves and blood healthy

Chang YF, et al