Can Glycine + Amino Acids Be the Secret to Deep, Rejuvenating Sleep?


With 20 million Americans dealing with occasional sleeplessness that can make life miserable, it’s no surprise many of us are always looking for a better way to get a great night’s sleep.1 A new sleep strategy is now focusing on supplementation with amino acids, with evidence suggesting these compounds may help you fall asleep faster, spend more time in deep sleep, and wake up more refreshed and clear-headed than with conventional sleep formulas.

Considered the building blocks of life, amino acids play many different health-promoting roles in the body, including helping with the formation of neurotransmitters.  These chemical signaling compounds enable nerve-to-nerve communication throughout the brain and nervous system, and are needed to support healthy sleep patterns.  

Some neurotransmitters send signals to the brain that help to keep us awake and alert; others regulate the body’s relaxation and mood responses, helping to instill calm, peaceful feelings of drowsiness; and others send the brain signals to fall asleep and stay asleep. Emerging evidence suggests that by targeting these neurotransmitter pathways with amino acid nutrition, we may normalize sleep patterns and promote high-quality sleep that refreshes mind and body.

Amino Sleep: A Novel Sleep Formula Featuring Glycine

Amino Sleep by ProHealth is a groundbreaking nutritional complex that features some of the most widely known sleep-supportive amino acids: Glycine, L-Tryptophan, 5-HTP, and L-Theanine. Let’s take a closer look at how these amino acids, presented in ProHealth’s Amino Sleep, may combine to support rejuvenating rest in a new and different way.

Glycine – 3 g

Helps You Wake Up Clear-Headed & Energized

Glycine is an amino acid that the body produces naturally. In the nervous system, glycine acts as an inhibitory neurotransmitter; this means when it reaches neurons, it calms them so they don’t “fire” with as much electrical activity.2 Glycine is also believed to lower core body temperature and to relax blood vessels at night; both these biological activities have been tied to sleep onset and sleep quality.3

  • In one study, volunteers who complained of sleep problems took either 3 g of glycine or placebo before bedtime and were then evaluated upon waking. In the glycine group, participants reported significant improvements after sleep across fatigue, liveliness, peppiness, and mental clarity.4
  • In another study, ten healthy male volunteers who had no sleep complaints were evaluated for sleep quality spending their usual time in bed, which was an average of 7.3 hours. These participants were then either given a placebo or 3 g of glycine and reduced their time in bed to 5.5 hours for three consecutive nights. At the study’s end, researchers reported glycine was associated with significant improvements in fatigue, daytime sleepiness, and daytime performance after nights where sleep was restricted.5

L-Tryptophan – 100 mg

Accelerates Sleep Onset; Extends Deep Delta-Wave Sleep

Stress and moodiness can wreak havoc on your sleep patterns. The amino acid L-Tryptophan may be perfectly suited to help with these concerns because it promotes a bright mood, relaxed mindset, and restful sleep patterns, all at the same time. L-Tryptophan has been suggested to be important in sleep management because, unlike some synthetic sleep aids, it is not associated with feelings of grogginess and brain fog upon waking.6

Did you know? L-Tryptophan may be especially helpful for women, because research has shown women with low L-Tryptophan levels appear to be more susceptible to mood concerns and relaxation difficulties that can make sleep challenging.7

A portion of the body’s circulating L-Tryptophan is delivered to the central nervous system (CNS), including the brain, where it is used to form neurotransmitters linked to relaxation and mood balance, including serotonin. In the brain, serotonin enhances production of melatonin, an important hormone for supporting normal circadian rhythm and restful sleep. In helping these brain chemicals, L-Tryptophan appears to support sleep:

In one placebo-controlled study of 15 subjects with mild sleep concerns, researchers tested the effects of taking 1 g L-Tryptophan vs. ¼ g of Tryptophan at bedtime. Researchers found that the 1 g dosage accelerated time to fall asleep, while the ¼ g dosage significantly increase the duration of restorative “delta-wave” deep sleep.8

Additional research has suggested that L-Tryptophan appears to help relieve obstructive sleep apnea (but has no effect on central sleep apnea). 9

Griffonia Simplicifolia (98% 5-HTP) – 102 mg

Increases Duration of REM Sleep By 47%

Griffonia Simplicfolia seeds supply 5-hydroxy L-Tryptophan (5-HTP), an amino acid metabolite that the body uses to make the relaxing neurotransmitter serotonin. Serotonin is an important contributor to tranquility and sleep, but is known to decline naturally in the body with age.10 Griffonia’s 5-HTP may help because it is considered to be easy-to-absorb and highly bioavailable, and is also one of the few nutrients that can cross the blood-brain barrier. Here, in the brain, 5-HTP directly influences serotonin and other neurotransmitters associated with mood, relaxation and sleep patterns.

One study, noting that low serotonin levels were associated with sleep problems, investigated how 5-HTP might help. After supplementing 12 healthy volunteers before bedtime, researchers found that 5-HTP appeared to increase duration of REM sleep by up to 47%, leading researchers to draw a correlation between serotonin levels and deep REM sleep.11

L-Theanine – 100mg

Supports Non-Sedating Relaxation Responses

Do you have an excitable personality and racing thoughts that make it hard to “turn off” your brain to fall asleep? L-Theanine in Amino Sleep may be perfect for you. L-Theanine is an amino acid found in green and black tea that may be partially responsible for these beverages’ calming and soothing effects. Like 5-HTP,L-Theanine is capable of crossing the blood barrier and directly influencing brain neurotransmitters, resulting in feelings of relaxation.

  • One research paper proposed that L-Theanine has soothing properties that may initiate high-quality sleep. Notably, researchers point out that L-Theanine does not promote sleep through sedation or drowsiness, but through relaxation. This led researchers to propose L-Theanine as a safe, natural aid for quality sleep without side effects.12

Looking to try a different kind of sleep formula? Supplying multiple evidence-backed amino acids, Amino Sleep by ProHealth offers broad-spectrum neurotransmitter support for deep, restful sleep – minus the grogginess and brain fog that may sometimes accompany some other sleep therapies.


3.    Kawai N, Sakai N, et al.  The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus, Neuropsychopharmacology, 2015, 40, 6, 1405
4.    INAGAWA, K., HIRAOKA, T., KOHDA, T., YAMADERA, W. and TAKAHASHI, M. (2006), Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms, 4: 75–77. doi: 10.1111/j.1479-8425.2006.00193.x  
5.    Bannai M, Kawai N, Ono K, et al. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Front Neurol. 2012;3:61. doi: 10.3389/fneur.2012.00061.
6.    Richard D, Dawes M, et al. L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. International Journal of Tryptophan Research 2009:2.
7.    Bell C., Abrams J., Nutt D. Tryptophan depletion and its implications for psychiatry. British Journal of Psychiatry 2001;178:399-405.   
8.    Hartmann E, Spinweber CL. Sleep induced by L-Tryptophan: Effect of dosages within the normal dietary intake. J Nerv Ment Dis. 1979;167(8):497–9.
9.    Schmidt HS. L-Tryptophan in the treatment of impaired respiration in sleep. Bull Eur Physiopathol Respir 19: 625–629, 1983
10.    Payton A, et al. Influence of serotonin transporter gene polymorphisms on cognitive decline and cognitive abilities in a nondemented elderly population. Molecular Psychiatry (2005) 10, 1133–1139. doi:10.1038/; published online 16 August 2005
11.    Wyatt RJ, Zarcone V, Engelman K, Dement WC, Snyder F, Sjoerdsma A. Effects of 5-hydroxytryptophan on the sleep of normal human subjects. Electroencephalogr Clin Neurophysiol. 1971;30:505–9.
12.    Rao TP, Ozeki M, et al. In Search of a Safe Natural Sleep Aid. J Am Coll Nutr. 2015 Mar 11:1-12.

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