Vitamin B12
Vitamin B12 (Cobalamin)
Also known as: Cobalamin, Methylcobalamin, Cyanocobalamin
An essential vitamin given by injection for deficiency and widely offered in wellness clinics for energy, though benefit without deficiency is limited.
Overview
Vitamin B12 is an essential nutrient required for red blood cell formation, nerve function, and DNA synthesis. Injectable B12 is a standard, approved treatment for deficiency and absorption disorders, where the benefit is clear. It is also commonly offered in wellness and IV clinics for energy and mood, but in people who are not deficient the evidence for these effects is limited. It is a vitamin, not a peptide.
Mechanism of action
Serves as a cofactor for enzymes in red blood cell production, nerve maintenance, and DNA synthesis.
Key studies & citations
- Review2013
Clinical practice. Vitamin B12 deficiency
Clinical review of diagnosis and treatment of B12 deficiency, including oral and parenteral replacement.
New England Journal of Medicine - Review2005
Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency
High-dose oral B12 (1,000 to 2,000 mcg) was as effective as injections for hematologic and neurologic responses in two RCTs.
Cochrane Database of Systematic Reviews
Frequently asked questions
Do B12 shots boost energy if I am not deficient?
If your B12 is already normal, injections are unlikely to add meaningful energy benefit. The clear value is in treating genuine deficiency.