What is Vitamin B12?
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that supports several critical processes in the body, including:
- Red blood cell production
- Build and repair DNA
- Support healthy nerve function
- Brain health and cognitive function
- Energy metabolism
The body cannot produce B12 on its own. You have to get it from food or supplements. B12 is found mainly in animal-based foods, including:
- Meat
- Fish
- Shellfish
- Eggs
- Dairy
Why Does Vitamin B12 Matter?
- Produces red blood cells in the bone marrow
- Maintains healthy nerve cells and neurological function
- Supports DNA production in every cell
- Converts nutrients from food into usable energy
- Helps regulate mood by producing brain chemicals like serotonin
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How to Interpret Vitamin B12
(Ranges may vary slightly by lab)
Standard reference ranges represent the middle 95% of healthy individuals but don’t necessarily reflect levels associated with longevity. Optimal ranges are derived from clinical guidelines, peer-reviewed research, and real-world outcomes data, with an emphasis on levels associated with peak functioning and reduced disease risk.
Benefits of Optimizing Vitamin B12
- Improved energy levels
- Enhanced cognitive function
- Better mood regulation
- Healthier neurological function
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Low Vitamin B12 Levels
Low vitamin B12 levels can cause a variety of symptoms related to energy, mental health, and cognitive function.
Symptoms:
- Extreme fatigue
- Lack of energy
- Pale skin
- Muscle weakness
- Sore tongue
- Memory issues
- Depression
- Numbness or tingling in hands and feet
- Balance problems
- Brain fog
Causes:
- Pernicious anemia
- Dietary restrictions such as vegan or vegetarian
- Crohn’s disease or celiac disease
- Certain medications (e.g., long-term use of acid-reducing medications such as proton-pump inhibitors; Metformin)
- Aging
Healthspan Impacts:
High Vitamin B12 Levels
High vitamin B12 levels are most commonly caused by supplementation or recent injections. Occasionally, elevated levels without supplementation may reflect underlying liver, kidney, inflammatory, or blood disorders.
Elevated vitamin B12 levels are usually caused by supplementation, but when high levels occur without supplements they may signal underlying health conditions.
Symptoms:
- Typically asymptomatic
Causes:
- B12 supplementation
- Liver disease
- Kidney failure
- Chronic inflammation
- Certain blood disorders
Healthspan Impacts:
- Persistently elevated B12 levels in people who aren’t supplementing are worth further evaluation.
How Hone Treats Out of Range Vitamin B12
A vitamin B12 blood test will be evaluated by your Hone physician alongside a CBC and kidney and liver function markers to determine whether low levels reflect true deficiency, absorption issues, or a functional problem.
- B12 injections – to treat severe malabsorption or pernicious anemia
- Oral B12 supplements (such as cyanocobalamin or methylcobalamin)* – to support low or borderline B12 levels
- Treatment of underlying GI conditions* – to reduce malabsorption issues
*Your Hone Physician does not prescribe these treatments but will recommend further evaluation and help coordinate care with your primary care provider when medical treatment is indicated.
- Eat more B12-rich foods such as meat, fish, shellfish, eggs, dairy (vegan and vegetarians may need to supplement more consistently)
- Reduce alcohol intake
- Manage chronic stress1
- Get high-quality sleep (at least 7-8 hours/night) and focus on a consistent sleep-wake schedule
- Regular exercise
Even modest improvements in sleep, movement, and meal timing can significantly improve glucose regulation within weeks.
Badar, A. (2022). Neuropsychiatric Disorders Associated With Vitamin B12 Deficiency: An Autobiographical Case Report. Cureus.
↑De Carvalho, L. P., et al. (2026). Vitamin B12 deficiency and its impact on healthcare: A population-level analysis and call for action. Frontiers in Nutrition.
↑Yahn, G. B., et al. (2020). Role of vitamin B12 deficiency in ischemic stroke risk and outcome. Neural Regeneration Research.
↑Dhonukshe-Rutten, R. A., et al. (2003). Vitamin B-12 Status Is Associated with Bone Mineral Content and Bone Mineral Density in Frail Elderly Women but Not in Men. The Journal of Nutrition.
↑Mazur, M., et al. (2025). Efficacy of sublingual and oral vitamin B12 versus intramuscular administration: Insights from a systematic review and meta-analysis. Frontiers in Pharmacology.
↑Zugravu, C. A., et al. (2021). Efficacy of supplementation with methylcobalamin and cyancobalamin in maintaining the level of serum holotranscobalamin in a group of plant-based diet (vegan) adults. Experimental and Therapeutic Medicine.
↑Altun, I., & Kurutaş, E. B. (2016). Vitamin B complex and vitamin B12 levels after peripheral nerve injury. Neural regeneration research.
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Reviewed for Accuracy by Our Medical Review Board
This biomarker information has been reviewed by a member of Hone’s medical review board. As part of the medical review team, physicians fact-check this content against the latest research and their own experience treating their patients.
Ashley Winter, M.D., is a board-certified urogynecologist trained at Weill Cornell and Cleveland Clinic. She specializes in female and male sexual dysfunction, urinary issues, genital pain, and hormone therapy.
James Staheli, D.O., is the Medical Director for Broad Health, Hone Health’s affiliated medical practice and a family medicine doctor in Atlanta, Georgia.
