Why we built a guide to low vitamin B12

b12guide.com is an independent site about vitamin B12 for readers in the United States. It focuses on three things: recognizing the signs of a deficiency, understanding lab results, and choosing a test or a supplement.

Why this site exists

The same three problems keep coming up. The symptoms of low B12, such as tiredness, tingling, and brain fog, are vague and easy to blame on something else. Lab reports list numbers like serum B12, MMA, and homocysteine, often with no explanation of what they mean. And a supplement shelf can hold a dozen forms and doses with no clear way to compare them. This site exists to answer those questions in plain English, with a source for every claim.

Who it is for

We write for adults in the United States who suspect they may be low in B12, or who have just received a lab report and want to understand it. Prices and availability on the site are for the United States.

Who writes it

b12guide.com is written by our editorial team. We do not publish the names of individual team members.

Medical review. Content is written by our editorial team and checked line by line against primary sources. We do not currently use an outside medical reviewer, and no page on this site has been reviewed by a doctor.

Where our information comes from

We rely on primary and official sources first: the NIH Office of Dietary Supplements, the NHS, MedlinePlus from the U.S. National Library of Medicine, research and reviews indexed in PubMed, and professional medical society guidelines. Every specific number, dose, and lab range is checked by a person against a cited primary source before it is published. Each page lists its sources at the bottom with the date we last checked them. Our editorial policy describes the full process.

What we do not do

We do not diagnose, we do not replace your doctor, and we do not give personal advice about which supplement or dose you should take. Read our medical disclaimer for details.

How the site is funded

Our content is free to read. If we add affiliate links, the site will be funded by commissions from testing services and dietary supplements. Sellers cannot pay to be included or ranked. Commissions do not decide what we write or how products are ranked; see our affiliate disclosure.

Get in touch

To report an error or ask a question, use our contact page. To start reading, see the guide to low B12 symptoms and levels.