Plain-English answers about low vitamin B12
Start with your symptoms, learn to read your lab results, then choose a B12 test or supplement, with a cited source behind every number.
Start here
Our guide to low B12 symptoms and levels takes you through the whole path on one page: the common early signs, a quick symptom check, what each number on your lab report means, and your options for testing and treatment.
How the guide works
- Check your symptoms. Compare what you feel with the signs most often linked to low B12, from tiredness to tingling hands and feet.
- Read your lab results. See the normal and low ranges for serum B12, MMA, homocysteine, MCV, and folate.
- Choose a test or supplement. Compare at-home and online B12 tests, and the main forms and doses of B12 supplements.
What this site covers
- Symptoms and signs of low B12
- How to read your B12 lab results
- Testing options and at-home test kits
- B12 supplement forms and doses
- Causes and who is at risk
Who this is for
Adults in the United States who think they may be low in B12, or who have just received a lab report and want to understand it.
How we work
- Sources: Our content is based on primary sources such as NIH ODS, the NHS, and research indexed in PubMed.
- Contact: To report an error or ask a question, see our contact page.
- Not medical advice: We explain the evidence; diagnosis and treatment decisions belong with your clinician.
This site offers general information only and is not a substitute for professional medical advice. Read our medical disclaimer.