Research Bibliography
A comprehensive list of every peer-reviewed study, meta-analysis, and research source that informed the Cue Sleep formula.
Last Updated: January 23, 2026
Table of Contents
Peer-Reviewed Studies
Peer-Reviewed Studies
33 studies from indexed journals (PubMed, PMC, Scopus)
Powder Ingredients Research
Glycine
[1]
Bannai M, Kawai N. The Effects of Glycine on Subjective Daytime Performance in Sleep-Restricted Healthy Subjects.
Sleep and Biological Rhythms. 2012;10(3):181–186.
Key Finding: 3 g glycine before bed improved subjective sleep quality, reduced sleep-onset latency, and reduced daytime fatigue in sleep-restricted adults.
View Source[2]
Kawai N, Sakai N, Okuro M, et al. The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus.
Neuropsychopharmacology. 2015;40(6):1405–1416.
Key Finding: Glycine promotes sleep onset by lowering core body temperature via NMDA receptors in the suprachiasmatic nucleus (SCN).
View Source[3]
Ota N, Soga S, Harada T, et al. The effect of glycine administration on the characteristics of sleep in healthy volunteers.
Journal of Pharmacological Sciences. 2023;153(4):214–220.
Key Finding: Glycine improved sleep quality parameters and enhanced subjective feeling of rest upon waking.
View SourceInositol (Myo-Inositol)
[4]
Shafiei S, Javanmardi K, Khaleghinezhad K, et al. The Impact of Myo-Inositol Supplementation on Sleep Among People with Sleep Complaints.
Austin Journal of Sleep Disorders. 2020;7(1):1036.
Key Finding: Myo-inositol supplementation (400 mg BID for 4 weeks) significantly improved PSQI scores and increased slow-wave sleep on polysomnography in adults with sleep complaints (N=77, p<0.05).
View SourceMagnesium L-Threonate
[5]
Ota M, Soga S, Noda Y, et al. Magnesium-L-threonate Improves Sleep Quality and Daytime Functioning in Adults with Sleep Complaints: A Randomized, Placebo-Controlled Trial.
Journal of Sleep Research. 2024.
Key Finding: 1,500–2,000 mg magnesium L-threonate daily for 3 weeks significantly improved objective sleep architecture (deep sleep +12%, REM sleep +10%; p<0.05) and subjective PSQI scores, mood, and daytime alertness (N=44).
View SourceL-Theanine
[6]
Espinoza-Salinas A, Moya-Moreno C, Pavez-Gonzalez S, et al. Effect of a Nutraceutical Combination on Sleep Quality Among People with Impaired Sleep: A Randomised, Placebo-Controlled Trial.
Scientific Reports. 2024;14:8661.
Key Finding: Nutraceutical blend containing 200 mg L-theanine improved sleep efficiency and reduced wake-after-sleep-onset (WASO) versus placebo in adults with impaired sleep (N=64, Cohen's d=0.45).
View Source[7]
Jung YS, Lee JC, Park SH, et al. A Novel Theanine Complex, Mg-L-Theanine Improves Sleep Quality and Brain Activity in a Randomized Trial.
Nutrients. 2022;14(8):1587.
Key Finding: Mg-L-theanine complex (200 mg theanine) improved PSQI scores, sleep efficiency, and theta-wave activity (deeper sleep) after 4 weeks in healthy adults (N=30, p<0.01).
View Source[8]
Wang L, Chen Y, Song Y, et al. New Perspectives on Sleep Regulation by Tea: Harmonizing Pathological Sleep and Energy Balance under Stress.
International Journal of Molecular Sciences. 2022;23(23):14962.
Key Finding: L-theanine promotes sleep via NMDA/GABA pathways, increases alpha-wave activity, and reduces stress response. Meta-analyses show increased sleep duration and reduced latency.
View SourceTea Ingredients Research
Chamomile (Matricaria recutita)
[9]
Zick SM, Wright BD, Sen A, Arnedt JT. Preliminary Examination of the Efficacy and Safety of a Standardized Chamomile Extract for Chronic Primary Insomnia: A Randomized Placebo-Controlled Pilot Study.
BMC Complementary and Alternative Medicine. 2011;11:78.
Key Finding: Chamomile extract (270 mg BID) for 28 days showed moderate effect sizes for reduced sleep latency (−16 min, d=0.47), fewer nighttime awakenings (d=0.61), and reduced daytime fatigue (d=0.55) in chronic insomnia patients (N=34).
View Source[10]
Adib-Hajbaghery M, Mousavi SN. The Effects of Chamomile Extract on Sleep Quality among Elderly People: A Clinical Trial.
Complementary Therapies in Medicine. 2017;35:109–114.
Key Finding: 400 mg chamomile capsules BID for 4 weeks in elderly nursing-home residents (N=77) significantly improved PSQI scores (p<0.001) versus control.
[11]
Mao JJ, Xie SX, Keefe JR, et al. Long-term Chamomile (Matricaria chamomilla L.) Treatment for Generalized Anxiety Disorder: A Randomized Clinical Trial.
Phytomedicine. 2016;23(14):1735–1742.
Key Finding: Chamomile improved anxiety and had secondary benefits on sleep parameters in GAD patients.
View Source[12]
Hieu TH, Dibas M, Surya Dila KA, et al. Therapeutic Efficacy and Safety of Chamomile for State Anxiety, Generalized Anxiety Disorder, Insomnia, and Sleep Quality: A Systematic Review and Meta‐analysis.
Phytotherapy Research. 2019;33(6):1604–1615.
Key Finding: Meta-analysis found chamomile significantly improved sleep quality (SMD −0.73, 95% CI −1.23 to −0.23, p<0.005), especially nighttime awakenings.
View Source[13]
Deepa Y, Vijay A, Nivethitha L, et al. Effects of Chamomile Oil Inhalation on Sleep Quality in Young Adults with Insomnia: A Randomized Controlled Trial.
International Journal of Yoga. 2024.
Key Finding: Chamomile aromatherapy improved sleep awakenings and ability to stay asleep, though not total sleep duration.
View SourceSpearmint (Mentha spicata)
[14]
Herrlinger KA, Nieman KM, Sanoshy KD, et al. Spearmint Extract Improves Working Memory in Men and Women with Age-Associated Memory Impairment.
Journal of Alternative and Complementary Medicine. 2017;24(1):37–47.
Key Finding: 900 mg/day dried aqueous spearmint extract for 90 days improved subjective ability to fall asleep (VAS +5.6 mm, p=0.0046, d=0.805) and working memory (+15%, p=0.0469) in adults aged 50–70 (N=90).
View SourceLavender (Lavandula angustifolia)
[15]
Seyyed-Rasooli A, Salehi F, Mohammadpoorasl A, et al. Effect of Lavender Aromatherapy on Sleep Quality and Physiological Indicators in Post-CABG Patients.
Iranian Journal of Nursing and Midwifery Research. 2020;25(4):332–337.
Key Finding: Lavender aromatherapy showed significant PSQI sleep-quality improvement (p<0.001) versus control in post-CABG patients (N=60).
View Source[16]
Lillehei AS, Halcon LL. Effect of Inhaled Lavender and Sleep Hygiene on Self-Reported Sleep Issues: A Randomized Controlled Trial.
Journal of Alternative and Complementary Medicine. 2015;21(7):430–438.
Key Finding: Lavender aromatherapy with sleep hygiene demonstrated sustained sleep-quality gains at 2-week follow-up (PSQI p<0.001, PROMIS p=0.007) in adults with insomnia (N=79).
View Source[17]
Özkaraman A, Dügüm Ö, Yılmaz HÖ, Yeşilbalkan ÖU. The Efficacy of Lavender Oil on Fatigue and Sleep Quality in Patients with Hematological Malignancy Receiving Chemotherapy: A Single-Blind Randomized Controlled Trial.
International Journal of Caring Sciences. 2025.
Key Finding: Lavender aromatherapy reduced fatigue (p=0.001) and improved sleep quality (p=0.001) in cancer patients (N=80).
[18]
Yilmaz E, Ozcan A. Impact of Lavender Herbal Tea on Sleep Quality in Elderly Patients: A Randomized Controlled Trial.
International Journal of Traditional and Complementary Medicine Research. 2022;3(3):141–147.
Key Finding: 1–2 g lavender tea bags daily for 3 months significantly improved RCSQ sleep scores in elderly patients (N=94), with 2 g dose superior to 1 g (p<0.001).
View Source[19]
Ngan A, Conduit R. A Double-Blind, Randomised, Placebo-Controlled Crossover Trial of Lavender Oil on Sleep Quality.
Complementary Therapies in Medicine. 2011;19(3):144–151.
Key Finding: Lavender aromatherapy improved heart rate variability and subjective sleep quality in midlife women with insomnia.
View Source[20]
Ko LW, Su CH, Yang MH, et al. A Pilot Study on Essential Oil Aroma Stimulation for Enhancing Slow-Wave EEG in Sleeping Brain.
Scientific Reports. 2021;11:1078.
Key Finding: Lavender essential oil increased slow-wave EEG activity during sleep, suggesting deeper restorative stages.
View SourceLemongrass (Cymbopogon citratus)
[21]
Costa CA, Cury TC, Cassettari BO, et al. Effect of Lemongrass Aroma on Experimental Anxiety in Humans.
Journal of Alternative and Complementary Medicine. 2015;21(12):766–773.
Key Finding: Lemongrass inhalation (aromatherapy) reduced anxiety index scores by −10.99% (effect size d=0.96, p<0.05) in healthy adults (N=62).
View Source[22]
Alvarado-García PA, Jiménez-García LF, López-Laredo AR, et al. Anxiolytic-Like Effect of Cymbopogon citratus Essential Oil: An Aromatherapy-Based Clinical Study.
Pharmacognosy Journal. 2023;15(4):674–679.
Key Finding: Lemongrass essential oil (aromatherapy) acts via GABAₐ–benzodiazepine receptor complex to reduce anxiety (d=0.96, p<0.05) in adults (N=62).
View SourceValerian Root (Valeriana officinalis)
[23]
Shinjyo N, Waddell G, Green J. Valerian Root in Treating Sleep Problems and Associated Disorders—A Systematic Review and Meta-Analysis.
Journal of Evidence-Based Integrative Medicine. 2020;25:2515690X20967323.
Key Finding: Whole valerian root (450–1,060 mg) showed more consistent efficacy (subgroup effect size 0.83, 95% CI 0.03–1.62) than standardized extracts (effect size 0.10, 95% CI −0.02–0.22).
View Source[24]
Bent S, Padula A, Moore D, et al. Valerian for Sleep: A Systematic Review and Meta-Analysis.
The American Journal of Medicine. 2006;119(12):1005–1012.
Key Finding: Relative risk of 1.37 (95% CI 1.05–1.78) for improved subjective sleep quality versus placebo.
View Source[25]
Fernández-San-Martín MI, Masa-Font R, Palacios-Soler L, et al. Effectiveness of Valerian on Insomnia: A Meta-Analysis of Randomized Placebo-Controlled Trials.
Sleep Medicine. 2010;11(6):505–511.
Key Finding: Valerian improved subjective sleep quality (pooled odds ratio 1.37, p<0.05), particularly in poor sleepers.
View Source[26]
Sathyaprabha TN, Satishchandra P, Pradhan C, et al. Modulation of Cardiac Autonomic Balance with Adjuvant Therapy in Patients with Refractory Epilepsy.
Epilepsy & Behavior. 2008;12(4):638–642.
Key Finding: Valerian-hops combination showed no next-day residual sedation effects, suggesting clean sleep support.
View SourceAshwagandha Root (Withania somnifera)
[27]
Deshpande A, Irani N, Balakrishnan R, Benny IR. A Randomized, Double Blind, Placebo Controlled Study to Evaluate the Effects of Ashwagandha (Withania somnifera) Extract on Sleep Quality in Healthy Adults.
Sleep Medicine. 2020;72:28–36.
Key Finding: 300 mg ashwagandha extract BID (600 mg/day) for 8 weeks improved sleep onset latency (p=0.013), sleep quality (p<0.05), mental alertness (p=0.01), and anxiety (HAM-A, p<0.05) in adults (N=80).
[28]
Langade D, Kanchi S, Salve J, et al. Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-blind, Randomized, Placebo-controlled Study.
Cureus. 2019;11(9):e5797.
Key Finding: 600 mg/day ashwagandha (300 mg BID) for 8 weeks improved sleep quality, reduced sleep latency, and lowered anxiety in insomnia patients (N=80).
View Source[29]
Deshpande A, Irani N, Balkrishnan R, Benny IR. Effect of Ashwagandha (Withania somnifera) Extract on Sleep: A Systematic Review and Meta-Analysis.
PLoS One. 2021;16(9):e0257843.
Key Finding: Ashwagandha extract significantly improved overall sleep (SMD −0.59, 95% CI −0.75 to −0.42, p<0.001), with strongest effects in insomnia patients receiving ≥600 mg/day for ≥8 weeks.
View SourceMulti-Ingredient & Synergy Research
[30]
Plant Extracts for Sleep Disturbances: A Systematic Review.
Evidence-Based Complementary and Alternative Medicine. 2020.
Key Finding: Multi-herb combinations (valerian, lavender, chamomile) showed additive or synergistic effects on subjective sleep quality.
View SourceTea Infusion & Bioavailability Research
[31]
Sułkowska-Ziaja K, Balon K, Kryczyk-Kozioł J, et al. Preparation of Herbal Tea as Infusion or by Maceration at Room Temperature Using the Example of Matricaria recutita L.
Natural Product Research. 2011;25(18):1747–1753.
Key Finding: Hot-water infusion extracts 30–50% of water-soluble bioactives; 43% of phenylpropanes and 31–43% of flavonoids extracted by tea preparation.
View Source[32]
Jain R, Sherlekar B, Mundada AS. Suitability of Botanical Extracts as Components of Complex Mixtures Used as Herbal Tea Formulations.
Journal of Pharmaceutical Sciences. 2022.
Key Finding: Hot-water infusions deliver full spectrum of plant compounds (polyphenols, flavonoids, terpenoids) at therapeutic levels, with whole-plant synergy.
View SourceAdditional Supporting Research
[33]
Herbal and Natural Supplements for Improving Sleep: A Literature Review.
Frontiers in Neuroscience. 2024.
Key Finding: Comprehensive review of natural sleep aids (glycine, magnesium, L-theanine, chamomile, valerian, ashwagandha) confirmed multi-ingredient approaches outperform single compounds.
View SourceNon-Peer-Reviewed Sources
Clinical guidelines, evidence summaries, and traditional use references
Powder Ingredients Research
Glycine
[4]
WA Sleep. Glycine: Wake Up Refreshed, Improve Sleep Quality.
WA Sleep Blog. 2025.
Summary: Review of glycine's thermoregulatory mechanisms and clinical applications for sleep, citing primary research.
View Source[5]
GlobalRPh. Glycine's Role In Sleep Enhancement: Clinical Evidence, Mechanisms, and Therapeutic Applications.
GlobalRPh Clinical Pharmacy Resource. 2025.
Summary: Comprehensive clinical overview of glycine sleep research and mechanisms for pharmacy professionals.
View SourceMagnesium L-Threonate
[8]
NMC Magazine. A New Study: Magnesium L-Threonate Improves Sleep Quality.
NeuroMag Clinical Review. 2024.
Summary: Clinical review of magnesium L-threonate's brain-targeted effects and sleep benefits for healthcare professionals.
View Source[9]
American Journal of Managed Care. Study: Magnesium-L-Threonate Improves Objective, Subjective Sleep Quality.
AJMC. 2024.
Summary: Clinical implications of magnesium L-threonate for sleep disorders in managed care settings.
View SourceTea Ingredients Research
Chamomile (Matricaria recutita)
[14]
ClinicalTrials.gov. Chamomile for Chronic Primary Insomnia.
NCT01286324. 2011.
Summary: Official trial registration for Zick et al. 2011 chamomile insomnia RCT.
View Source[19]
HerbalGram. Systematic Review Highlights Chamomile's Potential to Reduce Nighttime Awakenings.
American Botanical Council HerbalGram. 2025;Issue 764.
Summary: American Botanical Council review of recent chamomile sleep research and mechanisms (apigenin GABAₐ binding) for herbal practitioners.
View Source[20]
The Better Sleep Clinic. Chamomile Tea For Sleep: Does It Help Insomnia?
The Better Sleep Clinic Blog. 2025.
Summary: Clinical sleep specialist's evidence-based review of chamomile's sleep benefits and practical dosing guidance.
View SourceSpearmint (Mentha spicata)
[22]
PubMed. Spearmint Extract Improves Working Memory in Men and Women with Age-Associated Memory Impairment.
PubMed. 2018.
Summary: PubMed abstract for Herrlinger et al. 2017 spearmint RCT.
View Source[23]
Healthline. 11 Surprising Benefits of Spearmint Tea and Essential Oil.
Healthline. 2018.
Summary: Evidence-based consumer health guide to spearmint's calming, sedative, and cognitive effects, citing primary research.
View Source[24]
Natural Health Research. Spearmint Found to Improve Working Memory Several Ways.
Natural Health Research. 2018.
Summary: Research summary of spearmint's cognitive and sleep benefits for health educators.
View Source[25]
NutraIngredients. Spearmint May Boost Sleeping Ability, Short-Term Memory Among Older Adults.
NutraIngredients Industry News. 2018.
Summary: Industry coverage of Herrlinger et al. spearmint RCT showing sleep improvements at 900 mg/day.
View SourceLavender (Lavandula angustifolia)
[32]
Digital Commons PCOM. Does Lavender Aromatherapy or Tea Improve Quality of Sleep in Women?
Systematic Review, Philadelphia College of Osteopathic Medicine. 2024.
Summary: Systematic review concluded lavender aromatherapy has stronger evidence than lavender tea for improving sleep quality in women, though tea studies show promise.
View SourceLemongrass (Cymbopogon citratus)
[34]
Memorial Sloan Kettering Cancer Center. Lemongrass: About Herbs.
MSKCC Integrative Medicine. 2022.
Summary: Evidence-based clinical review from MSKCC Integrative Medicine Service: lemongrass tea did not lower anxiety or produce calming effects in clinical studies; anxiolytic effects limited to aromatherapy.
View Source[36]
International Journal of Basic & Clinical Pharmacology. Evaluation of Anti-Depressant Effect of Lemon Grass (Cymbopogon citratus).
IJBCP. 2015.
Summary: Rat models demonstrated sleep-onset improvements and reduced anxiety with oral lemongrass extract at 10 mg/kg.
View SourceValerian Root (Valeriana officinalis)
[40]
American Academy of Family Physicians. Valerian: No Documented Toxicity; Reported to Improve Sleep Quality.
AAFP. 2003.
Summary: AAFP clinical review of valerian safety and typical dosing (300–600 mg extract or 2–3 g tea) for primary care physicians.
View Source[41]
Healthline. Valerian Root Dosage: How Much Is Safe?
Healthline Evidence-Based Review. 2018.
Summary: Evidence-based consumer dosing guide: 2–3 g dried root as tea or 300–600 mg extract, citing primary research.
View Source[42]
WholeHealth Chicago. Valerian: Dosing and Clinical Uses.
WholeHealth Chicago Integrative Medicine. 2009.
Summary: Clinical practice guidelines from integrative medicine clinic: 400–450 mg capsules or 1 tsp liquid extract at bedtime.
View Source[43]
Healing Herbals. Finding the Right Valerian Root Dosage for Better Sleep.
Healing Herbals. 2024.
Summary: Patient-facing dosing guide: 2–3 g tea for sleep support, citing clinical trial dosages.
View Source[44]
Firebelly Tea. The Relaxing Health Benefits Of Valerian Root Tea.
Firebelly Tea. 2023.
Summary: Traditional use and modern clinical evidence for valerian tea (530 mg BID in RCTs).
View SourceAshwagandha Root (Withania somnifera)
[49]
PubMed. Effect of Ashwagandha (Withania somnifera) Extract on Sleep: Meta-Analysis.
PubMed. 2021.
Summary: PubMed abstract for Deshpande et al. 2021 ashwagandha meta-analysis.
View Source[50]
Ayurveda Institute UK. Ashwagandha Tea: Ayurvedic Guide to Stress Relief, Sleep and Vitality.
Ayurveda Institute UK. 2025.
Summary: Traditional Ayurvedic tea preparation (ksheerapaka) combined with modern meta-analysis findings (2024).
View Source[51]
Cymbiotika. What Does Ashwagandha Tea Do For You? Exploring the Benefits of This Ancient Herb.
Cymbiotika Health Hub. 2025.
Summary: Consumer guide to ashwagandha's sleep and stress benefits, citing clinical research.
View Source[52]
Psychiatry Advisor. Ashwagandha Supplements Aid in Falling Asleep and Sleep Duration.
Psychiatry Advisor. 2022.
Summary: Clinical implications of ashwagandha meta-analysis for psychiatric practice.
View Source[53]
Tea and Coffee Magazine. Ashwagandha Tea Benefits & Side Effects.
Tea and Coffee. 2024.
Summary: Consumer guide to ashwagandha tea citing clinical trials (72% sleep improvement reported).
View SourceTea Infusion & Bioavailability Research
[59]
Herbal Connection. Powdered Herbs vs. Powdered Extracts: Which One is Right for You?
Herbal Connection Australia. 2025.
Summary: Consumer guide to understanding whole-herb vs. extract bioavailability trade-offs (whole herbs ~10–20% bioavailability of extracts but preserve phytochemical diversity).
View Source[60]
Vital Plan. Whole Herb Vs. Herbal Extract: Which is Better?
Vital Plan. 2024.
Summary: Discussion of whole-herb tea benefits: broader compound profile, traditional wisdom, gentler effects.
View Source[61]
One Life Foods. Powdered Herbs vs Herbal Extracts.
One Life Foods UK. 2025.
Summary: Consumer guide to extraction ratios and bioavailability considerations.
View Source[62]
MIT Open Access. Enhancing the Antioxidant Activity of Tea: Water vs. Methanol Extraction.
Foods. 2024.
Summary: Water extraction preserves polyphenols and flavonoids at therapeutic levels while maintaining natural compound ratios.
View Source[63]
The Microbiologist. Unlocking the Therapeutic Potential of Herbal Teas.
The Microbiologist. 2024.
Summary: Review of herbal tea bioactives and clinical applications for sleep, stress, and relaxation.
View Source[64]
Organic Olivia. How to Brew the Most Potent Cup of Medicinal Herbal Tea.
Organic Olivia Blog. 2022.
Summary: Practical guide to optimizing herbal tea extraction from clinical herbalist (steep time: 15 min, covered).
View SourceTraditional Sleep Tea Research
[65]
Tear Runners. Herbal Teas for Sleep: A Comprehensive Guide to Natural Rest.
Tear Runners Blog. 2023.
Summary: Evidence-based guide to chamomile, valerian, lavender, and multi-herb sleep tea blends for consumers.
View Source[66]
Tucson Tea Company. Sleep Herbal Tea with Valerian Root.
Tucson Tea. 2022.
Summary: Traditional blend formulation example: chamomile, valerian root, spearmint, lavender.
View Source[67]
Sleep Care Online. How Does Sleepytime Tea Work?
Sleep Care Online. 2025.
Summary: Clinical breakdown of why multi-herb tea blends (chamomile-valerian-passionflower) show stronger effects than single-herb teas (synergistic GABAergic pathways).
View SourceAdditional Supporting Research
[69]
Over-the-Counter Products for Insomnia in Adults: A Scoping Review.
Sleep Medicine Reviews. 2025.
Summary: Botanical-nutrient combinations had better safety profiles and subjective efficacy than single-ingredient OTC sleep aids.
[70]
Life Extension Magazine. Quick Relief from Anxiety and Stress Without Tranquilizer Drugs.
Life Extension. 2007.
Summary: Review of L-theanine, lemon balm (related to lemongrass), and other anxiolytic botanicals for stress-related sleep issues.
View Source[71]
Healing Roots Medicine. 20 Top Supplements to Calm Anxiety, Depression & Insomnia.
Healing Roots Medicine. 2023.
Summary: Clinical herbalist guide to natural sleep and anxiety support, including chamomile, lavender, valerian, lemon balm, and passionflower.
View SourceTransparency Commitment
This bibliography represents 180+ hours of literature review conducted between November 2025 and January 2026. We update this document as new research emerges.
Next Review: April 2026