Zinc for ADHD
Verdict: Published with Warning
Across 6 PubMed studies, the evidence for Zinc 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 0.45
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published with Warning
Confidence
84%
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 = 0.45
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 negative 主導 (2 negative > 1 positive)，下層 RCT 不能推翻
- apply_hec_override — HEC-1 高階證據 negative — 強制由 C 改為 D
- 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
The effect of zinc supplementation in children with attention deficit hyperactivity disorder: A systematic review and dose-response meta-analysis of randomized clinical trials
Finding: Pooling 6 RCTs (489 school-aged children), zinc significantly reduced the ADHD TOTAL score (SMD -0.62 Hedges' g, 95% CI -1.24 to -0.002, p=0.04) but had NO significant effect on hyperactivity (SMD -0.93, 95% CI -3.31 to 1.45, p=0.44) or inattention (SMD 0.21, 95% CI -0.09 to 0.51, p=0.17); authors note small samples and low certainty.
View on PubMed The Role of Iron and Zinc in the Treatment of ADHD among Children and Adolescents: A Systematic Review of Randomized Clinical Trials
Finding: Across 9 RCTs (~693 participants; 5 assessed zinc sulfate), supplementation was associated with improvements in ADHD severity but effect sizes 'tended to be low and/or focused on specific ADHD symptoms'; authors conclude the role remains controversial, being 'most consistent with the evidence for zinc.'
View on PubMed Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder
Finding: In the largest zinc-ADHD RCT (N=400; zinc 202 vs placebo 198, 12 wk), zinc was superior to placebo for hyperactivity, impulsivity and impaired socialization but NOT for attention-deficit symptoms; full therapeutic response 28.7% (zinc) vs 20% (placebo).
View on PubMed Zinc sulfate as an adjunct to methylphenidate for the treatment of attention deficit hyperactivity disorder in children: a double blind and randomized trial [ISRCTN64132371]
Finding: Small adjunct RCT (N=44, 6 wk): adding zinc to methylphenidate gave significantly greater improvement than placebo+methylphenidate on both Parent (F=4.15, p=0.048) and Teacher (F=4.50, p=0.04) ADHD Rating Scales; concludes zinc 'might be beneficial' as supplementary medication.
View on PubMed Zinc status in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis of observational studies
Finding: Across 22 observational studies (1280 ADHD cases, 1200 controls), serum/plasma zinc did NOT differ overall (WMD -1.26 umol/L, 95% CI -3.72 to 1.20); only after excluding one outlier did ADHD show lower zinc (WMD -2.49 umol/L, 95% CI -4.29 to -0.69); hair zinc not significant (WMD -24.19, 95% CI -61.80 to 13.42).
View on PubMed Zinc for treating of children and adolescents with attention-deficit hyperactivity disorder: a systematic review of randomized controlled clinical trials
Finding: Reviewing 3 RCTs, the authors found insufficient evidence; the single well-controlled trial randomized by baseline zinc level showed zinc 'either alone or in combination with stimulants, did not improve ADHD', concluding more studies are needed to prove or disprove an effect.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4b EU EFSA
Supportive
contributes to normal function of the immune system source↗
L4c UK NHS
Cautious
You should be able to get all the zinc you need from your daily diet source↗
L4d TW TFDA / 衛福部
Supportive
鋅之每日最高攝食量不得超過30 mg source↗
L4e WHO
Supportive
zinc has been recommended by WHO and UNICEF as the only treatment to be coupled with oral rehydration salts for the treatment of all diarrhoea episodes source↗
L5a NIH Office of Dietary Supplements
Supportive
Zinc is an essential mineral involved in numerous aspects of cellular metabolism source↗
L5c Cleveland Clinic
Against
Vitamins and minerals claiming to treat ADHD have no scientific backing. In fact, they may interact with prescription medication. source↗
L5e Specialty Society (condition-mapped)
Cautious
The thing with those elements is they shouldn't be taken in large doses or by people who don't have a deficiency. That could lead to other health problems. One should treat a deficiency but not depend on these substances to correct ADHD. source↗