Supplement evidence

063 / 575Vitamin form

Cyanocobalamin

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The short answer

A stable, well-studied B12 form for prevention and treatment of deficiency.

Evidence and scope: Established for an indicated use
This status does not grade the ingredient for every goal, outcome, or person.
Important limitation: The benefit is tied to the stated indication, dose, and population; it is not evidence of broader disease prevention or longer life.
Before deciding: Key concern: Severe neurologic deficiency may require injections; Leber hereditary optic neuropathy needs specialist advice.

01 / PRACTICAL GUIDE

Dose, absorption, and combinations

These are indication-specific reference or studied ranges—not a personalized prescription. Start with the objective, then check the form, label, medicines, and health conditions.

Reference range by objective

Confirmed deficiencyOften 1,000–2,000 mcg/day orally when high-dose oral treatment is appropriate

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source ↗

More is not automatically better. A clinician or product label may specify a different amount.

Absorption / solubilityWater-soluble

Water-soluble or readily water-dispersible. This does not mean excess is always harmless.

How it is commonly taken

May be taken with or without food.

Do not combine casually

Severe neurologic deficiency may require injections; Leber hereditary optic neuropathy needs specialist advice.

Dose and use source ↗

Dose and use links lead to primary or official source material. Search links are discovery tools, not proof that every returned paper applies.

02 / EVIDENCE

What the research says

We keep supportive, mixed, negative, safety, and contextual findings together. The headline never replaces the underlying papers.

3research papers in this ledger

3unique primary studies represented

125unique participants represented

These are audited counts for this JIVANA collection, not search-result totals. Participants are counted once when multiple papers use the same cohort; review papers are not added again to participant totals.

Open the research timelineResearch timeline

Entries are ordered by publication year. A study period appears only when the source reports it.

2017

Mixed or qualifiedPMID 28421567

Early biomarker response and patient preferences to oral and intramuscular vitamin B12 substitution in primary care

Both routes increased B12 and holotranscobalamin over 4 weeks, with much larger circulating values after injections. The study was small, short, and unblinded and primarily informs early biomarker response and patient preference, not long-term clinical equivalence.

Published: 2017Duration: 28 daysn=37 participants

Study design and methods

Design: Randomized, nonblinded, parallel-group active comparison
Population: 37 primary-care patients with vitamin B12 deficiency
Intervention: Oral cyanocobalamin 1,000 μg/day or intramuscular hydroxocobalamin 1,000 μg weekly
Outcome: B12, holotranscobalamin, homocysteine, methylmalonic acid, adherence, and route preference

Open research record ↗

2011

Mixed or qualifiedPMID 21232119 · ISRCTN22063938

Oral vitamin B12 for patients suspected of subtle cobalamin deficiency

One month lowered methylmalonic acid and raised serum B12 but did not change homocysteine or hematologic indices. The methylmalonic-acid difference was gone after 3 months without treatment, showing that a short course did not provide durable correction.

Published: 2011Duration: 4 weeks of treatment with 3 months off treatmentn=50 participants

Study design and methods

Design: Multicenter randomized, observer-blind, placebo-controlled pragmatic trial
Population: 50 primary-care and nursing-home patients with serum B12 of 125–200 pmol/L
Intervention: Oral cyanocobalamin 1,000 μg/day or placebo for 4 weeks
Outcome: Methylmalonic acid, serum B12, homocysteine, hematocrit, and mean corpuscular volume

Open research record ↗

1998

Supports a specific usePMID 9694707

Effective treatment of cobalamin deficiency with oral cobalamin

Hematologic and neurologic correction was similar, while oral treatment produced higher B12 and lower methylmalonic acid at 4 months. The small complete-case trial supports high-dose oral replacement but does not show that every cause or severity can avoid injections.

Published: 1998Duration: 120 daysn=38 participants

Study design and methods

Design: Randomized active-route comparison trial
Population: 38 adults with newly diagnosed cobalamin deficiency; 33 remained evaluable after excluding folate deficiency
Intervention: Oral cyanocobalamin 2 mg/day or intramuscular cyanocobalamin 1 mg on a loading then monthly schedule
Outcome: Hematologic and neurologic response, serum B12, methylmalonic acid, and homocysteine

Open research record ↗

Unscreened discovery appendix—not evidence76 candidate publicationsSearch run: Aug 21, 2026

Complete for the displayed PubMed query at the search timestamp—not for all databases or every possible synonym. Candidates can be irrelevant, duplicate the same study, or report negative findings. They are never summed as evidence or participants until screened.

03 / SOURCES

Start with the source material

Official evidence overviewPubMed bounded human-evidence search Live PubMed discovery searchNational Library of Medicine

The live search is for discovery only. Search-result counts change and are not included in the audited totals above.

Recent PubMed discovery recordsDirect links to the first 12 records returned by the reproducible search. These are discovery candidates—not reviewed summaries or a count of supportive findings.

04 / EXPERT CONTEXT

Expert context—not evidence

Expert positions are dated context—not scientific evidence. They never raise the evidence status or become consensus by repetition.

No direct, source-verified endorsement is currently recorded. Research authorship or discussion alone is not treated as endorsement.