Vitamin B9 (Folic Acid)
Pteroylmonoglutamic acid (folic acid) / 5-methyltetrahydrofolate (5-MTHF)
Also known as: Folic acid, folate, 5-MTHF, methylfolate, L-methylfolate, Metafolin
This ingredient is classified as unclassified risk (GIRI score: 3.5/10).
Safety Profile
Known Safety Concerns
- Masks vitamin B12 deficiency — allows neurological damage to progress undetected
- Unmetabolised folic acid accumulation in MTHFR gene variant carriers
- Possible colorectal cancer promotion at high doses in individuals with pre-malignant lesions
- UL: 1,000 mcg/day of synthetic folic acid
Contraindications
- Masks vitamin B12 deficiency — allows neurological damage to progress undetected
- Unmetabolised folic acid accumulation in MTHFR gene variant carriers
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
Folic acid supplementation is critical for prevention of neural tube defects in pregnancy. However, high-dose folic acid can mask vitamin B12 deficiency (correcting megaloblastic anaemia while allowing neurological damage to progress). Unmetabolised folic acid (UMFA) accumulates in individuals with MTHFR polymorphisms. Some evidence suggests high folate may promote colorectal cancer progression in individuals with existing pre-malignant lesions. The UL is 1,000 mcg/day.
Biological and Chemical Classification
- Scientific Name
- Pteroylmonoglutamic acid (folic acid) / 5-methyltetrahydrofolate (5-MTHF)
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Evidence unavailable.
No peer-reviewed studies with traceable links have been retrieved for this ingredient. Use the button below to fetch evidence from PubMed.
Score Transparency
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)
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.
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.
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.
Final GIRI Score for Vitamin B9 (Folic Acid). 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.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Low classification for Vitamin B9 (Folic Acid)
A score of 3.5 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.