Sleep and Biological Rhythms

, Volume 5, Issue 2, pp 126–131 | Cite as

Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes

  • Wataru Yamadera
  • Kentaro InagawaEmail author
  • Shintaro Chiba
  • Makoto Bannai
  • Michio Takahashi
  • Kazuhiko Nakayama
Original Article


In human volunteers who have been continuously experiencing unsatisfactory sleep, effects of glycine ingestion (3 g) before bedtime on subjective sleep quality were investigated, and changes in polysomnography (PSG) during sleep were analyzed. Effects on daytime sleepiness and daytime cognitive function were also evaluated. Glycine improved subjective sleep quality and sleep efficacy (sleep time/in-bed time), and shortened PSG latency both to sleep onset and to slow wave sleep without changes in the sleep architecture. Glycine lessened daytime sleepiness and improved performance of memory recognition tasks. Thus, a bolus ingestion of glycine before bedtime seems to produce subjective and objective improvement of the sleep quality in a different way than traditional hypnotic drugs such as benzodiazepines.

Key words

amino acid glycine slow wave sleep latency St Mary’s Hospital Sleep Questionnaire Stanford Sleepiness Scale 


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  1. 1.
    Inagawa K, Hiraoka T, Kohda T, Yamadera W, Takahashi M. Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep Biol. Rhythms 2006; 4: 75–7.CrossRefGoogle Scholar
  2. 2.
    Inagawa K, Kawai N, Ono K, Sukegawa E, Tsubuku S, Takahashi M. Assessment of acute adverse events of glycine ingestion at high doses in human volunteers. J. Urban Life Health Assoc. 2006; 50: 27–32.Google Scholar
  3. 3.
    Buysse DJ, Reynolds CF III, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatr. Res. 1989; 29: 193–213.CrossRefGoogle Scholar
  4. 4.
    Doi Y, Minowa M, Uchiyama M, Okawa M. Development of the Pittsburgh Sleep Quality Index Japanese Version. Jpn J. Psychiatr. Treat. 1998; 13: 755–68 (in Japanese).Google Scholar
  5. 5.
    Ellis BW, Johns MW, Lancaster R, Raptopoulos P, Angelopolos N, Pereist RG. The St. Mary’s Hospital sleep questionnaire: a study of reliability. Sleep 1981; 4: 93–7.PubMedGoogle Scholar
  6. 6.
    Uchiyama M, Ohta K, Okawa M. [Evaluation standards of sleep and sleep disorder.] In: Matsushita M, ed. [Encyclopedia of Clinical Psychiatry, Vol. 13, Sleep Disorder.] Tokyo: Nakayama Shoten, 1999; 489–98 (in Japanese).Google Scholar
  7. 7.
    Rechtschaffen A, Kales A. A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. Washington, DC: Public Health Service, US Government Printing Office, 1968.Google Scholar
  8. 8.
    Hoddes E, Zarcone V, Smythe H, Phillips R. Quantification of sleepiness: a new approach. Psychophysiology 1973; 10: 431–6.CrossRefPubMedGoogle Scholar
  9. 9.
    Monk TH. A visual analogue scale technique to measure global vigor and affect. Psychiatr. Res. 1989; 27: 89–99.CrossRefGoogle Scholar
  10. 10.
    Monti JM. Sleep laboratory and clinical studies of the effects of triazolam, flnitrazoram and flurazepam in insomniac patients. Methods Find. Exp. Clin. Pharmacol. 1981; 3: 303–26.PubMedGoogle Scholar
  11. 11.
    Parrino I, Terzano MG. Polysomnographic effects of hypnotics: a review. Psychopharmacology 1996; 126: 1–16.CrossRefPubMedGoogle Scholar
  12. 12.
    Roth T, Roehrs TA. A review of the safety profiles of benzodiazepine hypnotics. J. Clin. Psychiatry 1991; 52.Google Scholar
  13. 13.
    Holbrook AM, Crowther R, Lotter A, Cheng C, King D. Meta-analysis of benzodiazepines use in the treatment of insomnia. Can. Med. Assoc. J. 2000; 162: 225–33.Google Scholar
  14. 14.
    Roehrs TA, Merlotti L, Zorick F, Roth T. Sedative, memory, and performance effects of hypnotics. Psychopharmacology 1994; 116: 130–4.CrossRefPubMedGoogle Scholar
  15. 15.
    Seki S, Ono-Takesue K, Yoshida S, Inagawa K, Murakami N, Takahashi M. Accumulation of peripheral glycine in the pineal body. Bull. Jpn Soc. Neurochem. 2004; 43: 558.Google Scholar

Copyright information

© Japanese Society of Sleep Research 2007

Authors and Affiliations

  • Wataru Yamadera
    • 1
  • Kentaro Inagawa
    • 2
    Email author
  • Shintaro Chiba
    • 3
  • Makoto Bannai
    • 2
  • Michio Takahashi
    • 2
  • Kazuhiko Nakayama
    • 1
  1. 1.Department of PsychiatryJikei University School of MedicineTokyoJapan
  2. 2.Research Institute for Health FundamentalsAjinomoto Co. Inc.Kawasali-shi, 210-8681 KanagawaJapan
  3. 3.Ohta Memorial Sleep CenterOhta General HospitalKawasakiJapan

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