Global Ingredient Risk Index Vitamins & Minerals

Vitamin B12

Also known as: Cobalamin, Cyanocobalamin, Methylcobalamin, Adenosylcobalamin, Hydroxocobalamin, Vitamin B-12

28 მარ 2026

LOW RISK 1.0/10 How?

This ingredient is classified as unclassified risk (GIRI score: 1.0/10).

Known Safety Concerns

Deficiency risk in vegans; impaired absorption with metformin; confirm active Methylcobalamin form

Contraindications

Deficiency risk in vegans; impaired absorption with metformin; confirm active Methylcobalamin form

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Information not yet available for this ingredient profile.

Vitamin B12 (cobalamin) is an essential water-soluble vitamin required for DNA synthesis (one-carbon methylation cycle), myelin sheath maintenance (neurological function), red blood cell formation (megaloblastic anaemia prevention), and energy metabolism via methylmalonyl-CoA mutase. Available in multiple forms: Cyanocobalamin (synthetic, stable, widely used), Methylcobalamin (biologically active, no conversion required — preferred for neurological conditions), Adenosylcobalamin (mitochondrial form), and Hydroxocobalamin (used clinically for cyanide poisoning treatment). Deficiency is common in vegans and vegetarians (dietary B12 is exclusively in animal products), elderly (reduced gastric intrinsic factor), and metformin users (B12 absorption impaired by metformin — monitor annually). Generally very safe even at high doses — water-soluble and renally excreted. No established UL (Tolerable Upper Intake Level) set by EFSA or IOM. Confirm active Methylcobalamin form on product label — particularly important for vegan supplement lines. Rare anaphylaxis with parenteral administration.

Information not yet available for this ingredient profile.

SETI Score 50/100

Risk Level High risk

Scientific Confidence Low

Evidence Strength Limited

Key Benefit Vitamins & Minerals

Key Safety Concern Deficiency risk in vegans; impaired absorption with metformin; confirm active Methylcobalamin form

Evidence Reviewed 10 PubMed studies

Scientific Confidence Low

Based on study quality, consistency, and recency

Executive Summary — Ingredient Assessment

SETI Score 50/100

Risk Level High risk

Evidence Strength Limited

Main Benefit Vitamins & Minerals

Main Safety Concern Deficiency risk in vegans; impaired absorption with metformin; confirm active Methylcobalamin form

Ingredient Vitamin B12

Scientific Evidence Overview

10 studies reviewed
0 high-quality studies (meta-analysis or RCT)
Main clinical benefit observed: Vitamins & Minerals
Evidence consistency: High consistency across studies (100%)

Safety Signals

Deficiency risk in vegans; impaired absorption with metformin; confirm active Methylcobalamin form

Evidence Strength Limited

Final Scientific Assessment

The available scientific evidence for Vitamin B12 indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.

Ingredient Vitamin B12

Evidence reviewed 10 peer-reviewed studies (last 10 years)

50 /100

Total SETI Score

High risk

Evidence quality	10/40
Evidence consistency	20/20
Safety signals	0/20
Study recency	10/10
Evidence transparency	10/10

Evidence Summary

10 studies reviewed
0 high-quality studies (meta-analysis or systematic review)
0 studies identified benefits or no safety concern (GREEN)
10 studies reported limited or advisory safety evidence (YELLOW)

Evidence Policy

Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.

Last updated: 06 აპრ 2026, 12:09

Evidence Distribution

10 Other / unclassified

Observational / other LOW evidence YELLOW
Celiac Disease Unveiled by Palmoplantar Pigmentation. ↗

PMID 41936991 ↗

Journal Am J Med

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41936991/

Jain A. Celiac Disease Unveiled by Palmoplantar Pigmentation.. Am J Med. 2026. PMID:41936991.
Observational / other LOW evidence YELLOW
[Thrombotic microangiopathy caused by vitamin B12 and folate deficiency (pseudo-TMA)]. ↗

PMID 41936033 ↗

Journal Orv Hetil

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41936033/

Ku00f3bor K et al.. [Thrombotic microangiopathy caused by vitamin B12 and folate deficiency (pseudo-TMA)].. Orv Hetil. 2026. PMID:41936033.
Observational / other LOW evidence YELLOW
Rapidly Progressive Dementia Secondary to Vitamin B12 Deficiency: A Case Report. ↗

PMID 41935355 ↗

Journal Curr Alzheimer Res

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41935355/

Xu R et al.. Rapidly Progressive Dementia Secondary to Vitamin B12 Deficiency: A Case Report.. Curr Alzheimer Res. 2026. PMID:41935355.
Observational / other LOW evidence YELLOW
Maternal nutrition as a key determinant of placental and developing blood-brain barrier xenobiotic protective functions. ↗

PMID 41935021 ↗

Journal J Physiol

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41935021/

Connor KL et al.. Maternal nutrition as a key determinant of placental and developing blood-brain barrier xenobiotic protective functions.. J Physiol. 2026. PMID:41935021.
Observational / other LOW evidence YELLOW
Saliva as a Matrix for Primary Care: Feasibility and Scoping of its Use for Assessment of Nutrition and Inflammation. ↗

PMID 41933704 ↗

Journal Adv Nutr

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41933704/

Fahim SM et al.. Saliva as a Matrix for Primary Care: Feasibility and Scoping of its Use for Assessment of Nutrition and Inflammation.. Adv Nutr. 2026. PMID:41933704.
Observational / other LOW evidence YELLOW
Perception and acceptance of micronutrient-Fortified Bouillon among Non-Index Household Members: A longitudinal sub-study nested within a randomized trial in Northern Ghana. ↗

PMID 41931601 ↗

Journal PLoS One

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41931601/

Kyereh FK et al.. Perception and acceptance of micronutrient-Fortified Bouillon among Non-Index Household Members: A longitudinal sub-study nested within a randomized trial in Northern Ghana.. PLoS One. 2026. PMID:41931601.
Observational / other LOW evidence YELLOW
Case Report: Marchiafava-Bignami disease: anti-parietal cell antibodies as a potential etiological factor in a novel case presentation. ↗

PMID 41930251 ↗

Journal Front Mol Biosci

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41930251/

Zhang J et al.. Case Report: Marchiafava-Bignami disease: anti-parietal cell antibodies as a potential etiological factor in a novel case presentation.. Front Mol Biosci. 2026. PMID:41930251.
Observational / other LOW evidence YELLOW
Evaluation of Vitamin B12 Deficiency Among Patients with Type 2 Diabetes Mellitus on Metformin at Hoima Regional Referral Hospital, Uganda. ↗

PMID 41924591 ↗

Journal Diabetes Metab Syndr Obes

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41924591/

Ali HO et al.. Evaluation of Vitamin B12 Deficiency Among Patients with Type 2 Diabetes Mellitus on Metformin at Hoima Regional Referral Hospital, Uganda.. Diabetes Metab Syndr Obes. 2026. PMID:41924591.
Observational / other LOW evidence YELLOW
Sex-Specific Heart Rate Variability Associations With Vitamin B12, Folate, and Iron Status. ↗

PMID 41923733 ↗

Journal Rev Cardiovasc Med

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41923733/

u00d6zyau015far M et al.. Sex-Specific Heart Rate Variability Associations With Vitamin B12, Folate, and Iron Status.. Rev Cardiovasc Med. 2026. PMID:41923733.
Observational / other LOW evidence YELLOW
Characteristics of women who fast during pregnancy: Findings from Kuwait Birth Cohort Study. ↗

PMID 41919344 ↗

Journal Br J Nutr

Year 2026

Study type Observational / other

Evidence strength LOW evidence

PubMed link https://pubmed.ncbi.nlm.nih.gov/41919344/

Al-Taiar A et al.. Characteristics of women who fast during pregnancy: Findings from Kuwait Birth Cohort Study.. Br J Nutr. 2026. PMID:41919344.

Q × L × D × S × 10 = 1.0 / 10

The GIRI Score is the product of four independently computed evidence components, each normalised to 0–1, then scaled to 0–10. Every component is derived exclusively from peer-reviewed references and regulatory data — no editorial judgement is applied.

0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.

Method: Q = number of approved references ÷ 10 (capped at 1.0)

50%

Limited — mostly case reports or animal studies

Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.

Benefit

Risk

50%

Mixed or neutral — roughly equal benefit and risk signals

Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.

50%

One or more monitoring-level safety signals active

Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.

0Q × 5L × 5D × 5S = 1.0 / 10

Final GIRI Score for Vitamin B12. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.

Full methodology & data sources

The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.

References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.

LOW RISK 1.0/10

Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.

LOW
0–3.0

MODERATE
3.0–5.5

HIGH
5.5–7.5

CRITICAL
7.5–10

1.0

The score pin shows exactly where this ingredient falls on the fixed risk scale.

What drove the Low classification for Vitamin B12

A score of 1.0 places this ingredient in the Low band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.

0 approved references.

Limited — mostly case reports or animal studies (Level 4–5).

Neutral or mixed — benefit and risk signals roughly balanced.

No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.

No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).

How are the Low / Moderate / High / Critical thresholds defined?

The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:

Level	Score	Meaning
LOW	0.0 – 2.9	Sparse or predominantly beneficial evidence. No active safety alerts.
MODERATE	3.0 – 5.4	Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups.
HIGH	5.5 – 7.4	Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended.
CRITICAL	7.5 – 10	Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision.

Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.

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Vitamin B12

Safety Profile

Known Safety Concerns

Contraindications

Interactions

Evidence and Scientific Findings

Ingredient Overview

Biological and Chemical Classification

Mechanism of Action

Clinical Evidence of Effectiveness

Pharmacokinetics

Recommended Dosage

SETI — Scientific Evidence Transparency Index

Executive Summary — Ingredient Assessment

Evidence Summary

Evidence Policy

Evidence Distribution

Score Transparency

Risk Level Classification

What drove the Low classification for Vitamin B12

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