トリプトファン ： 入眠困難
B エビデンス 少なくとも1件のランダム化試験がこれを支持しており、おおむね一貫した結果が得られています。合計96名の参加者を対象とした19件の研究（メタアナリシス1件、RCT 1件を含む）に基づく。19件中16件の研究で肯定的な効果が示されている。
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B
結論
Tryptophan shows promising signs for helping people fall asleep faster, supported by a strong biological rationale, though the studies so far have been quite small.
- 84% of 19 studies show positive effects — a very consistent finding
- Works through conversion to serotonin and then melatonin in the brain
- Total participant count of only 96 limits the strength of conclusions
- Includes 1 meta-analysis and 1 RCT — larger trials are needed
Key Study Findings
Review
Effects of L-tryptophan on sleepiness and on sleep.
Dose: 1 g or more
vs: Placebo
効果: Increase in subjective sleepiness; decrease in sleep latency
review
Unraveling the connection between the Mediterranean diet and sleep health: from biological mechanisms to clinical …
Dose: Mediterranean diet (high adherence vs. low adherence); polyphenols, omega-3, fiber as key components
vs: Placebo
効果: None
None
Animal study
Ginsenoside Rg1 alleviates PCPA-induced insomnia by inhibiting NLRP3 inflammasome activation and pyroptosis through the Nrf2/HO-1 …
Dose: None
vs: Placebo
効果: None
None
Animal Study
Promotion of sleep by cinnamic acid in parachlorophenylalanine-induced insomnia in rats.
Dose: Cinnamic acid (CA) administered to rats (dose not specified)
vs: Placebo
効果: None
None
Animal study
Lactobacillales derived from traditional Xizang dairy products improve insomnia and restore neurotransmitter-metabolic profiles via gut …
Dose: Mixed probiotics (Lactobacillus helveticus L551, Lacticaseibacillus paracasei L578, Streptococcus th
vs: Placebo
効果: None
None
Animal study
Wendan Decoction exerts therapeutic effects on insomnia by regulating gut microbiota and tryptophan metabolism.
Dose: None
vs: Placebo
効果: None
None
Key Statistics
19
研究数
96
参加者数
↑
Positive
B
グレード
Referenced Papers
Journal of psychiatric …
None
102 件の引用
Psychopharmacology
2025
5 件の引用
Phytomedicine : international …
2025
5 件の引用
Microbiological research
2025
3 件の引用
International immunopharmacology
2025
1 件の引用
Sleep & breathing …
2025
Neurochemical research
2024
14 件の引用
Journal of ethnopharmacology
2024
13 件の引用
Journal of ethnopharmacology
2024
13 件の引用
Phytomedicine : international …
2023
33 件の引用
The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression.
Meta-Analysis
Nutrition reviews
2022
68 件の引用
Study on the hypnotic effect of rare protopanaxadiol-type and protopanaxatriol-type ginsenosides.
Other
RSC advances
2019
13 件の引用
Drugs & aging
2018
131 件の引用
Nutrition research and …
2018
12 件の引用
Journal of clinical …
2017
1097 件の引用
Biomedical reports
2015
12 件の引用
European journal of …
2014
43 件の引用
Pharmacology, biochemistry, and …
2008
76 件の引用
Psychopharmacology
1983
25 件の引用
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
一般的な使用量
- sleep:
- 250-1,000 mg, before bed
上限量： Not established; previously recalled (1989) due to contamination
研究で検討された用量
| 用量 | 期間 | 効果 | N |
|---|---|---|---|
| 1 g or more | -- | Positive | -- |
| Mediterranean diet (high adherence vs. low adherence); polyphenols, omega-3, fiber as key components | -- | Positive | -- |
| None | -- | Positive | -- |
| Cinnamic acid (CA) administered to rats (dose not specified) | -- | Positive | -- |
| Mixed probiotics (Lactobacillus helveticus L551, Lacticaseibacillus paracasei L578, Streptococcus th | -- | Positive | -- |
| None | -- | Positive | -- |
| cannabidiol (CBD) at various doses administered to mice | -- | Positive | -- |
| not specified (intragastric administration) | -- | Positive | -- |
推奨摂取タイミング： 30-60 minutes before bed, ideally on a light stomach
Safety & Side Effects
報告されている副作用
- ⚠ Nausea
- ⚠ Diarrhea
- ⚠ Drowsiness
- ⚠ Dry mouth
- ⚠ Blurred vision
既知の相互作用
- ● SSRIs/SNRIs — risk of serotonin syndrome
- ● MAOIs — dangerous serotonin accumulation
- ● Sedatives — additive drowsiness
耐容上限摂取量： Not established; previously recalled (1989) due to contamination
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 トリプトファン help with 入眠困難?
Based on 19 studies with 96 participants, there is moderate evidence from clinical studies that トリプトファン may support 入眠困難 management. Our evidence grade is B (Good Evidence).
How much トリプトファン should I take for 入眠困難?
Studies have used various dosages. A commonly studied range is 250-1,000 mg, before bed. Always consult your healthcare provider before starting any supplement regimen.
Are there side effects of トリプトファン?
Reported side effects may include Nausea, Diarrhea, Drowsiness, Dry mouth. Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.
How strong is the evidence for トリプトファン and 入眠困難?
We rate the evidence as Grade B (Good Evidence). This rating is based on 19 peer-reviewed studies with 96 total participants. The overall direction of effect is positive.
Related Evidence
References
- [1] E Hartmann. J Psychiatr Res. Effects of L-tryptophan on sleepiness and on sleep. doi:10.1016/0022-3956(82)90012-7 PubMed
- [2] Jingyi Li et al.. Psychopharmacology (Berl). 2025. Ginsenoside Rg1 alleviates PCPA-induced insomnia by inhibiting NLRP3 inflammasome activation and pyroptosis through the Nrf2/HO-1 pathway in mice. doi:10.1007/s00213-025-06828-5 PubMed
- [3] Yuan Tian et al.. Phytomedicine. 2025. Wendan Decoction exerts therapeutic effects on insomnia by regulating gut microbiota and tryptophan metabolism. doi:10.1016/j.phymed.2025.157028 PubMed
- [4] Peifan Li et al.. Microbiol Res. 2025. Lactobacillales derived from traditional Xizang dairy products improve insomnia and restore neurotransmitter-metabolic profiles via gut microbiota in PCPA-induced mice. doi:10.1016/j.micres.2025.128276 PubMed
- [5] Xiaona Ye et al.. Int Immunopharmacol. 2025. Promotion of sleep by cinnamic acid in parachlorophenylalanine-induced insomnia in rats. doi:10.1016/j.intimp.2025.114852 PubMed
- [6] Tatiana Palotta Minari et al.. Sleep Breath. 2025. Unraveling the connection between the Mediterranean diet and sleep health: from biological mechanisms to clinical implications. doi:10.1007/s11325-025-03546-2 PubMed
- [7] Yu-Meng Liu et al.. Neurochem Res. 2024. Cannabidiol Exerts Sedative and Hypnotic Effects in Normal and Insomnia Model Mice Through Activation of 5-HT1A Receptor. doi:10.1007/s11064-024-04102-2 PubMed
- [8] Haiqin Ren et al.. J Ethnopharmacol. 2024. The therapeutic potential of Ziziphi Spinosae Semen and Polygalae Radix in insomnia management: Insights from gut microbiota and serum metabolomics … doi:10.1016/j.jep.2024.118255 PubMed
- [9] Tian-Ji Xia et al.. J Ethnopharmacol. 2024. Shen Yuan extract exerts a hypnotic effect via the tryptophan/5-hydroxytryptamine/melatonin pathway in mice. doi:10.1016/j.jep.2024.117992 PubMed
- [10] Yan Yan et al.. Phytomedicine. 2023. Screening the effective components of Suanzaoren decoction on the treatment of chronic restraint stress induced anxiety-like mice by integrated chinmedomics … doi:10.1016/j.phymed.2023.154853 PubMed
- [11] Clarinda N Sutanto et al.. Nutr Rev. 2022. The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression. doi:10.1093/nutrit/nuab027 PubMed
- [12] Ning Mou et al.. RSC Adv. 2019. Study on the hypnotic effect of rare protopanaxadiol-type and protopanaxatriol-type ginsenosides. doi:10.1039/c9ra01549c PubMed
- [13] Vivien C Abad et al.. Drugs Aging. 2018. Insomnia in Elderly Patients: Recommendations for Pharmacological Management. doi:10.1007/s40266-018-0569-8 PubMed
- [14] Ki-Bae Hong et al.. Nutr Res Pract. 2018. Two combined amino acids promote sleep activity in caffeine-induced sleepless model systems. doi:10.4162/nrp.2018.12.3.208 PubMed
- [15] Michael J Sateia et al.. J Clin Sleep Med. 2017. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice … doi:10.5664/jcsm.6470 PubMed
- [16] Meng-Fei Ye et al.. Biomed Rep. 2015. Flos Albiziae aqueous extract and its active constituent quercetin potentiate the hypnotic effect of pentobarbital via the serotonergic system. doi:10.3892/br.2015.518 PubMed
- [17] Chenning Zhang et al.. Eur J Pharmacol. 2014. Pharmacological evaluation of sedative and hypnotic effects of schizandrin through the modification of pentobarbital-induced sleep behaviors in mice. doi:10.1016/j.ejphar.2014.09.012 PubMed
- [18] Li-En Wang et al.. Pharmacol Biochem Behav. 2008. Spinosin, a C-glycoside flavonoid from semen Zizhiphi Spinozae, potentiated pentobarbital-induced sleep via the serotonergic system. doi:10.1016/j.pbb.2008.03.022 PubMed
- [19] E Hartmann et al.. Psychopharmacology (Berl). 1983. Chronic insomnia: effects of tryptophan, flurazepam, secobarbital, and placebo. doi:10.1007/BF00427957 PubMed
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