B12 that won't hold.
A clinical investigation guide for adults whose B12 status keeps drifting low despite consistent supplementation. Four pathways by which an unsuspected H. pylori infection can impair B12 absorption and retention — even with daily tablets.
A workup for the B12 that won't stick.
This guide is written for the patient who has been told 'just take B12' — and then watched the labs drift down again. It maps four pathways by which an unsuspected H. pylori infection can impair B12 absorption and retention, even with consistent oral supplementation.
It is not a treatment protocol. It is the diagnostic conversation, written down, so the next appointment is more specific than the last.
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i.
The clinical signature of B12 deficiency that won't holdHow the picture differs from dietary, vegan, and post-bariatric deficiency patterns.
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ii.
Four pathways the standard workup missesIntrinsic factor depletion, atrophic gastritis, hypochlorhydria, autoimmune overlap — with the evidence tier for each.
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iii.
Why 'serum B12' isn't the same as 'B12 status'Holotranscobalamin, methylmalonic acid, homocysteine — the labs that move first.
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iv.
Labs to request beyond serum B12MMA, holotranscobalamin, homocysteine, anti-IF, gastrin — read together.
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v.
Testing options for H. pyloriStool antigen, urea breath test, biopsy — trade-offs, costs, and what each rules in or out.
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vi.
What positivity changesEradication, B12 re-test, supplementation route reconsidered — what to expect at 6 and 12 months.
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vii.
A conversation script for the next appointmentThree questions, phrased clinically, that route the workup toward the gastric pathway without overstating the case.
How an unsuspected infection keeps B12 leaking out.
B12 deficiency in the presence of H. pylori rarely runs through a single pathway — it stacks. The guide treats each as testable, with the evidence tier explicit.
Intrinsic factor depletion
Chronic H. pylori infection drives parietal cell loss in the gastric body, reducing intrinsic factor secretion required for B12 ileal uptake.
Atrophic gastritis
Sustained H. pylori-associated inflammation progresses to atrophic gastritis in a subset of carriers, compounding the absorption deficit over time.
Hypochlorhydria
Stomach acid is required to cleave B12 from dietary proteins before binding to intrinsic factor. Chronic infection alters acidity and disrupts this first step.
Autoimmune overlap
H. pylori has been associated with anti-IF and anti-parietal-cell antibody emergence in genetically susceptible hosts — the pernicious anaemia cascade.
Sharper questions. Better appointments.
The guide doesn't replace a clinician. It gives you the language, the labs, and the literature — so the visit is a clinical conversation, not a search.
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Recognise the clinical signature of B12 deficiency that won't hold and how it differs from dietary, post-bariatric, and vegan-pattern deficiency.
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Name the four pathways — intrinsic factor depletion, atrophic gastritis, hypochlorhydria, autoimmune overlap — by which H. pylori can keep B12 status drifting.
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Request the right secondary labs — MMA, holotranscobalamin, homocysteine, anti-IF, gastrin — and read them in combination, not in isolation.
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Decide between testing options — stool antigen, urea breath test, biopsy — based on cost, accuracy, and your specific clinical context.
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Bring a structured conversation to your physician — three concrete questions that route the workup toward the gastric pathway and reconsider the supplementation route if indicated.
Three tiers. One rubric. No exceptions.
Every claim in this guide is tagged with one of three evidence tiers. The summary below previews the four claims central to the case for investigating H. pylori in B12 deficiency that won't hold. The full reference list — fifteen citations — sits at the back of the PDF.
B12 deficiency · evidence summary
A few honest questions.
Is this medical advice?
No. It is an investigation guide — written to inform the conversation with a clinician. Diagnosis and treatment decisions belong to your physician.
Do I need to buy the testing kit?
No. The guide is content, sold separately from any Welyon product. It covers all three standard testing options — stool antigen, urea breath test, biopsy — and tells you what each costs and how to ask for it through your existing physician or insurer.
What if my labs are 'in range'?
The guide spends a section on this exact situation — what 'in range' obscures, what to look at in combination, and the secondary markers that frequently shift the picture without changing the headline numbers.
Refund policy?
14 days, no questions. If the guide isn't useful, the Lemon Squeezy receipt has a one-click refund link. We track this to keep the guides accountable.
Who wrote it?
The investigation series is authored by Welyon's editorial team and is being reviewed by the scientific advisory board currently in formation. Reviewer names will appear in the front matter of each guide upon confirmation.
Stop topping up the same leaking bucket. Find the leak.
36 pages, fifteen citations, four pathways, one clear path to a sharper appointment. PDF, instant download.
FDA disclaimer · Commercial interest
These statements have not been evaluated by the Food and Drug Administration. This guide is for informational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your physician before acting on any information presented here.
Commercial interest disclosure. Welyon produces an at-home H. pylori testing kit and a physician-supervised Foundation Protocol referenced in this guide. The presence of these products is disclosed throughout — including on this page, the guide cover, and in the front matter of the PDF — and does not change the content of the guide. The investigation steps described would apply equally if neither product existed.
Editorial independence. Evidence grading in this guide follows the same three-tier rubric used across the H. Pylori Investigation Series, applied identically regardless of whether the resulting investigation routes a reader toward — or away from — Welyon's products.