L-Theanine for ADHD
Verdict: Insufficient Evidence
Across 4 PubMed studies, the evidence for L-Theanine in ADHD grades Tier U — unverified / insufficient. Research is still too limited to draw a firm conclusion.
U ⚫ U Unverified Insufficient Evidence
Why this grade7-layer evidence engine
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Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.40
D
C
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A
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← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
U · Insufficient Evidence
Confidence
64%
Broadly consistent
Evidence level
E6
Multiple smaller RCTs (n<500)
▸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 = 0.403
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- 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 (4)L2 · primary research & systematic reviews
The effects of L-theanine (Suntheanine) on objective sleep quality in boys with ADHD: a randomized, double-blind, placebo-controlled clinical trial
Finding: 400mg/day L-theanine significantly improved sleep percentage and sleep efficiency vs placebo in ADHD-diagnosed boys over 6 weeks; outcome is sleep quality, NOT core ADHD symptoms (inattention/hyperactivity) directly.
View on PubMed Effects of l-theanine-caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT
Finding: L-theanine-caffeine combination improved total cognition composite and d-prime with a trend toward improved inhibitory control; effects of L-theanine alone vs combination are not cleanly separable from the abstract. n=5, proof-of-concept only.
View on PubMed Effects of L-theanine-caffeine combination on selective attention among adolescents with ADHD: a double-blind, placebo-controlled, crossover study
Finding: High-dose L-theanine-caffeine combination improved neural resource allocation, stabilized reaction speed, and reduced false alarms in adolescents with ADHD (n=21, 3-way crossover).
View on PubMed The effects of L-theanine supplementation on the outcomes of patients with mental disorders: a systematic review
Finding: SR concludes L-theanine reduced psychiatric symptoms more effectively than control across a bundle of disorders including ADHD; conclusion sentence is NOT ADHD-specific (bundles schizophrenia + anxiety + ADHD together), so it cannot be read as a dedicated ADHD effect-size finding.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
FDA has no questions source↗
L4b EU EFSA
Against
a cause and effect relationship has not been established between the consumption of L-theanine from Camellia sinensis and improvement of cognitive function source↗
L4d TW TFDA / 衛福部
Neutral
茶氨酸為茶葉中天然存在之胺基酸成分 source↗
L5e Specialty Society (condition-mapped)
Cautious
Step away from the supplement aisle — there are better ways to help your kid feel calm. source↗