Iron for ADHD
Verdict: Published with Warning
Across 6 PubMed studies, the evidence for Iron in ADHD grades Tier C — weak evidence. Effective, but with safety or population caveats.
C 🟠 C Weak Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.46
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published with Warning
Confidence
82%
Highly consistent evidence
Evidence level
E2
Multiple high-quality MAs (≥2 independent, consistent)
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.464
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (0 positive vs 1 negative)，由 raw_score 決定
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Iron Supplementation in Management of Neurodevelopmental Disorders: Systematic Review, Meta-Analysis, and Qualitative Synthesis
Finding: In the hyperactivity meta-analysis (3 RCTs, n=124) the iron group had a large within-group effect (Cohen's d=1.70) vs placebo (d=0.76), and in inattention (2 RCTs, n=75) iron d=3.19 vs placebo d=1.66, but the BETWEEN-GROUP differences were NOT statistically significant and the evidence was graded very low quality.
View on PubMed Psychiatric and cognitive outcomes of iron supplementation in non-anemic children, adolescents, and menstruating adults: A meta-analysis and systematic review
Finding: Pooled RCT data (18 studies incl. 12 RCTs, n=1408) showed iron improved anxiety (d=0.34), fatigue (d=0.34), cognition/intelligence (d=0.46) and short-term memory (d=0.53), but had NO significant effect on attention and no significant effect on depression in RCTs.
View on PubMed Effects of iron supplementation on attention deficit hyperactivity disorder in children
Finding: Ferrous sulfate 80 mg/day for 12 weeks produced a significant within-group ADHD Rating Scale decrease (-11.0 +/- 13.9, P<0.008) vs no change on placebo (3.0 +/- 5.7, P=0.308) and lowered CGI-Severity (P<0.01), but Conners parent (P=0.055) and teacher (P=0.076) scales did not reach significance and the trial was very small with a 3:1 randomization (iron n=18, placebo n=5).
View on PubMed Effects of Iron Supplementation on Attention Deficit Hyperactivity Disorder in Children Treated with Methylphenidate
Finding: Adding ferrous sulfate to methylphenidate for 12 weeks (n=50) improved the conduct subscale within the iron group (P=0.003) and some subscales at specific timepoints (learning problems wk1-6 P=0.007; conduct/psychosomatic wk7-12), but there was NO significant overall between-group difference in score changes between iron and placebo.
View on PubMed Iron Status in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis
Finding: Across 10 studies (n=2191, 1196 ADHD) serum ferritin was significantly lower in ADHD (SMD=-0.40, 95% CI -0.66 to -0.14), whereas serum iron did NOT differ (SMD=-0.026, 95% CI -0.29 to 0.24); this shows a correlation between low iron stores and ADHD, not that supplementation treats ADHD.
View on PubMed Iron and attention deficit/hyperactivity disorder: What is the empirical evidence so far? A systematic review of the literature
Finding: Of ~20 studies assessing peripheral iron status the results were MIXED (both significant and non-significant ferritin-ADHD associations); only two small supplementation trials (one open-label, one pilot RCT) showed improvement in some but not all ADHD measures, and iron deficiency may reduce psychostimulant effectiveness.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
NUTRIENT SUPPLEMENT source↗
L4b EU EFSA
Supportive
contributes to normal oxygen transport in the body source↗
L4c UK NHS
Cautious
You should be able to get all the iron you need from your daily diet. source↗
L4d TW TFDA / 衛福部
Supportive
育齡婦女及懷孕婦女每日建議攝取鐵量為15毫克，至懷孕第3期婦女則應增加每日攝取量至45毫克。 source↗
L4e WHO
Supportive
Daily oral iron and folic acid supplementation is recommended as part of antenatal care source↗
L5a NIH Office of Dietary Supplements
Supportive
Iron is an essential component of hemoglobin source↗
L5b Mayo Clinic
Cautious
Some promising research studies indicate that iron supplements likely help people manage ADHD if they have deficiencies in iron. source↗
L5e Specialty Society (condition-mapped)
Cautious
Frequently, the elements zinc, magnesium, and iron are studied in relationship to ADHD. One should treat a deficiency but not depend on these substances to correct ADHD. These elements shouldn't be taken in large doses or by people who don't have a deficiency, as that could lead to other health problems. source↗