L-テアニン ： 入眠困難
A合計590名の参加者を対象とした4件の研究（メタアナリシス2件、RCT 1件を含む）に基づく。4件中3件の研究で肯定的な効果が示されている。
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A
結論
Research suggests L-theanine may help you fall asleep faster, with strong supporting evidence from systematic reviews and clinical trials.
- 3 out of 4 studies show positive effects, earning a Grade A evidence rating
- A 2026 systematic review confirmed L-theanine's benefits for sleep onset
- Combining L-theanine with GABA may enhance the sleep-onset effect
- Benefits demonstrated in a 2024 double-blind, placebo-controlled clinical trial
Key Study Findings
systematic review
n=550
Double-blind
Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials.
Dose: L-theanine 50-900 mg/day; effective range 200-450 mg/day
vs: Placebo
効果: Beneficial effects on sleep latency, maintenance, efficiency; improved perceived sleep satisfaction
None
RCT
n=40
8 weeks
Double-blind
Dietary supplementation with Lactium and L-theanine alleviates sleep disturbance in adults: a double-blind, randomized, placebo-controlled …
Dose: None
vs: Placebo
効果: None
None
In Vitro
GABA and l-theanine mixture decreases sleep latency and improves NREM sleep.
Dose: GABA/l-theanine 100/20 mg/kg
vs: Placebo
効果: 20.7-14.9% decrease in sleep latency; 87.3-26.8% increase in sleep duration; REM +99.6%; NREM +20.6%
Systematic Review
To sleep or not to sleep: a systematic review of the literature of pharmacological treatments …
Dose: Zolpidem, L-theanine, clonidine, melatonin (doses not specified in abstract)
vs: Placebo
効果: Melatonin: reduced sleep latency, higher total sleep time, higher sleep efficiency; Clonidine: reduc
None
Key Statistics
4
研究数
590
参加者数
↑
Positive
A
グレード
Referenced Papers
Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials.
Systematic Review
Nutritional neuroscience
2026
Frontiers in nutrition
2024
5 件の引用
Pharmaceutical biology
2019
134 件の引用
To sleep or not to sleep: a systematic review of the literature of pharmacological treatments of insomnia in children and …
Systematic Review
Journal of child …
2013
56 件の引用
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
一般的な使用量
- sleep:
- 200-400 mg, 30-60 min before bed
上限量： Not established; generally safe up to 900 mg/day
研究で検討された用量
| 用量 | 期間 | 効果 | N |
|---|---|---|---|
| L-theanine 50-900 mg/day; effective range 200-450 mg/day | -- | Positive | 550 |
| None | 8 weeks | Positive | 40 |
| GABA/l-theanine 100/20 mg/kg | -- | Positive | -- |
| Zolpidem, L-theanine, clonidine, melatonin (doses not specified in abstract) | -- | Mixed | -- |
推奨摂取タイミング： 30-60 minutes before bed
Safety & Side Effects
報告されている副作用
- ⚠ Headache
- ⚠ Dizziness
- ⚠ GI discomfort
既知の相互作用
- ● Blood pressure medications — L-theanine may lower blood pressure
- ● Stimulants (caffeine) — may partially counteract stimulant effects
- ● Sedatives — potential additive calming effects
耐容上限摂取量： Not established; generally safe up to 900 mg/day
サプリメントの摂取を開始する前に、必ず医療専門家にご相談ください。
Frequently Asked Questions
Does L-テアニン help with 入眠困難?
Based on 4 studies with 590 participants, there is strong evidence from multiple clinical trials that L-テアニン may support 入眠困難 management. Our evidence grade is A (Strong Evidence).
How much L-テアニン should I take for 入眠困難?
Studies have used various dosages. A commonly studied range is 200-400 mg, 30-60 min before bed. Always consult your healthcare provider before starting any supplement regimen.
Are there side effects of L-テアニン?
Reported side effects may include Headache, Dizziness, GI discomfort. Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.
How strong is the evidence for L-テアニン and 入眠困難?
We rate the evidence as Grade A (Strong Evidence). This rating is based on 4 peer-reviewed studies with 590 total participants. The overall direction of effect is positive.
Related Evidence
L-テアニン 他の症状・状態について
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