Vitamin B12

Tier-BPublic-ready6/28/2026

Blood-Level or Deficiency Marker is closer to a research marker, so it should be read separately from a directly felt benefit.

The 56.0 score includes research signals from patient or disease contexts. General supplement evidence is not repeated enough, so the B tier remains conservative.

Representative tier calculated from paper evidence that passed the collection audit.

Papers analyzed

Caution signal

Low

Context-specific research signal

56.0

Blood-Level or Deficiency MarkerGlucose and metabolic health markersStress Response and Sleep Changes

Main benefit evidence

The representative ingredient tier is calculated from these target-level evidence groups.

Nutrient status and deficiency

4 studiesTier-B

Blood-Level or Deficiency Marker

Fairly consistent positive signal in studiesResearch marker focusPatient-group study

This is based on lab markers such as blood levels, deficiency correction, or absorption. Read it separately from directly felt outcomes.

Evidence score

54.6

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Glucose and metabolic health

1 studiesTier-C

Glucose and metabolic health markers

Some positive signal observedResearch marker focusPatient-group study

This card is closer to a measured biomarker or lab outcome than a directly felt user benefit. These findings come from a defined study population, so everyday effects may differ.

Evidence score

37.2

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Stress and mood

1 studiesTier-C

Stress Response and Sleep Changes

Some positive signal observedFelt benefit focusPatient-group study

These findings come from stress response, cortisol, anxiety, or sleep outcomes. They may mix felt benefits with physiological markers.

Evidence score

22.8

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Recent research

Updated This Month10 new papers

Observed range in repeated studies

This range includes studies in specific patient groups. It is not a general dose or recommendation.

Lower observed study value

mcg/day

7 independent studies

Higher observed study value

1000

mcg/day

Only ranges repeated in human, oral, single-ingredient studies are shown.

Not personal dosing instructions, recommendations, or safety limits.

Side effects and combination findings in studies

Findings from studies of this ingredient alone are separated from findings involving another supplement or medication.

Caution index

0.9

Caution band: Low

Caution signals

Side effects + combos + curated rules

Key precautions

No curated contraindication rule is available yet, but literature caution signals are shown below.

These are signals reported in studies. They do not predict what will happen to an individual.

Findings to review with care

Side effects reported for the ingredient alone are separated from findings involving another supplement or medication.

Side effects reported when this ingredient was used alone

Symptoms or adverse events reported in studies of this ingredient without another active ingredient.

Adverse effect signal1 papers

The study reported a high prevalence of vitamin B12 hypervitaminosis (excess) among vegetarian and vegan children, associated with over-supplementation, though the clinical impact is unknown.Human studies · Study type not identified

Caution signals when used with another supplement or medication

These studies reported a negative change, reduced absorption, or another caution when substances were used together. They do not predict an individual outcome.

메트포르민The review mentions that chronic use of metformin is associated with an increased risk of vitamin B12 deficiency due to interference.

양성자 펌프 억제제The review mentions that chronic use of proton-pump inhibitors is associated with an increased risk of vitamin B12 deficiency due to interference.

위산 저하제(ALA)와 메트포르민Concomitant use of acid-lowering agents and metformin was associated with a lower serum vitamin B12 concentration, indicating a potential additive adverse effect on B12 status.

발프로산Higher cobalamin levels were reported in children with valproate-treatment, suggesting a potential interaction.

Proton Pump Inhibitors (PPIs)Long-term use of PPIs is reported to be associated with an increased risk of vitamin B12 deficiency, particularly in men aged 18-40.

헬리코박터 파일로리The review mentions that vitamin B12 deficiency may be worsened by Helicobacter pylori infection.

알코올Alcohol use is listed as a risk factor for vitamin B12 deficiency in the context of patients requiring screening.

엽산A case report mentioned that folic acid supplementation in a patient with an untreated cobalamin deficiency resulted in psychiatric-neurological symptoms.

제산제Reviewed that antacids may alter the absorption and utilization of cobalamin, increasing the risk of deficiency in the elderly.

Evidence summaries

Paper IDs and full lists are private. Only study types and summaries are shown.

Key Evidence #1

Public scholarly dataCitation signal: 214

observational

It is found that the effect of probiotics in enhancing host resistance to pathogen infections depended on function of B_12 produced by an anaerobic indigenous gut microbe, Cetobacterium, which exhibited the ability to strengthen the interactions within gut mic

Key Evidence #2

Public scholarly dataCitation signal: 199

observational

There is a lack of randomised controlled trials and prospective studies focusing specifically on the relation between B12 and oxidative stress in humans, resulting in a low strength of evidence, and further work is warranted.

Key Evidence #3

Public scholarly dataCitation signal: 189

review

A list of criteria for a cost-effective vitamin B12 deficiency screening in metformin-treated patients is proposed, which could serve as a practical guide for identifying individuals at high risk for this condition.

3 more summariesLimited representative sample by study type.

Public scholarly dataCitation signal: 175

observational

These randomized trial data from a large cohort of women at high risk of CVD indicate that daily supplementation with folic acid/B6/B12 may reduce the risk of age-related macular degeneration.

Public scholarly dataCitation signal: 155

review

The reduction of vitamin B12 may be induced by metformin in a dose dependent manner, as compared with placebo or other anti-hyperglycemic therapy.

Public scholarly dataCitation signal: 147

observational

A previously unrecognized decrease in brain vitamin B12 status across the lifespan is revealed that may reflect an adaptation to increasing antioxidant demand, while accelerated deficits due to GSH deficiency may contribute to neurodevelopmental and neuropsych

Vitamin B12

Evidence score: 56.0|Caution index: 0.9

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