Glycine (2-Aminoacetic Acid, Gly, G) is a conditionally essential amino acid and neurotransmitter. The simplest of all amino acids, glycine plays a role in the synthesis of nucleic acids, glutathione, RNA and DNA, and creatine.[i]
Glycine is considered a “conditionally essential” amino acid because your body cannot produce enough on its own. So, the remainder must be obtained from foods like meat, fish, dairy, legumes, or supplements.[iii]
Glycine plays a critical role as a neurotransmitter because it controls your intake of food, behavior, and complete body homeostasis.
It can be both excitatory and inhibitory. Which means that it can stimulate your brain and nervous system, as well as quieten it.
Supplementing with glycine has been shown to effective in treating metabolic disorders, inflammatory disease, obesity, cancers, and diabetes.
Here we’ll investigate as a nootropic for enhancing sleep quality and brain function.
- Sleep: Glycine helps you fall asleep more quickly, reduce insomnia, improve sleep quality, and promote deeper and more restful sleep
- Neurological disorders: Glycine has been shown to be effective in those dealing with schizophrenia, OCD, and depression.
- Stroke: Patients who have suffered ischemic stroke (brain ischemia or cerebral ischemia), are given glycine orally to help limit damage to the brain within the first six hours of the stroke.
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Glycine was discovered in 1829 by French chemist Henri Braconnot after boiling gelatin with sulphuric acid. And since then, it has been manufactured and distributed commercially as a sweetener, and as a buffering agent for antacids.
Glycine is also a sweet and colorless crystal that is synthesized in your body from choline, threonine, and serine.
As a therapeutic and nootropic supplement provides multiple benefits to human health.
Glycine has been shown to be effective for improving skin elasticity. And collagen peptide which is loaded with Glycine helps suppress sun-induced skin damage and reduce wrinkles around the eyes.[iv]
Glycine supplementation helps reduce the symptoms of schizophrenia.[v] It helps reduce symptoms of OCD. And low blood levels of glycine have been associated with depression.
Glycine modulates inhibitory neurotransmitters via glycine receptors throughout the central nervous system.[vi] And potentiates NMDA receptors which provides an excitatory response.[vii] Affecting cognition, mood, immune function, and sleep.
How does Glycine work in the brain?
Glycine boosts brain health and function in several ways. But two in particular stand out.
- For sleep – Numerous studies have shown that glycine influences the quality of sleep, reduces insomnia, and promotes restful sleep. It does this in a couple of ways.
In other words, glycine works to improve blood flow to the body’s extremities, which in turn reduces core body temperature.
This decrease in body temperature plays an important part of sleep induction since the onset of sleep is associated with lowered body temperature. Which then progresses to deep sleep.
Researchers demonstrated this in an animal study showing how glycine triggered a drop in body temperature which helped the study subjects fall asleep more quickly And spend more time in REM sleep. [viii]
The study also showed that glycine can help you experience deep, slow wave sleep more quickly.
Studies also suggest that glycine can help you get back to your regular sleep cycles after a period of a disrupted sleep schedule.[x]
- Schizophrenia – Glycine has shown promising results in reducing the symptoms of depression, OCD, anxiety, and bipolar disorder. However, its most pronounced efficacy is seen in the reduction of schizophrenia symptoms.
Post mortem evaluations of the brains of people with schizophrenia have shown fewer NMDA receptors compared to those who did not have the disease.
Researchers also found decreased levels of glycine in both the blood and cerebrospinal fluid of people with schizophrenia.[xi]
Glycine is known to be an NMDA agonist. It is well tolerated by the patients in both short-, and long-term treatment.
To date, numerous studies have been conducted to evaluate the efficacy of glycine in treating schizophrenia.
The first controlled trial used a glycine dose of 15 grams per day which showed significant improvement during glycine treatment.
Another study, 21 schizophrenic patients were given high doses of glycine in addition to antipsychotic treatment.
A significant 34% reduction in negative symptoms was observed during glycine treatment. And the study authors noted the improvement persisted even after patients stopped supplementing with glycine. [xii]
Sleep deprivation or the inability to get a good night’s sleep is an increasing concern world-wide. Not enough sleep or poor sleep quality can result in:
↓ Memory loss
↓ Inability to concentrate
↓ Poor metabolism
↑ Weight gain
↑ High blood pressure
↑ High blood sugar levels
↓ Low sex drive
↑ Risk of heart disease
Low glycine levels in the body are also linked to depression.[xv]
Glycine activates NMDA receptors in the brain and restores serotonin levels which helps improve sleep. And the ability to fall asleep faster.
In one study, 15 adult females were given either a placebo or 3 grams of glycine before bed.
The study concluded that supplementing with glycine showed a significant improvement in reduced fatigue, liveliness, and clear-headedness the next morning.[xvi]
Glycine helps brain cell signaling which boosts cognition, memory and mood.
Glycine taken in high doses has proven to be highly effective in reducing the symptoms of schizophrenia.
It helps with depression and mental fluency associated with schizophrenia.
And may improve psychotic symptoms as well.[xvii]
Evidence also suggests that glycine assists with depression and neurodegenerative diseases such as Alzheimer’s and Huntington’s.
Glycine also showed a protective effect against neurological damage associated with stroke.[xviii]
And research suggests improvements in memory, recall, and sustained attention in those supplementing with glycine as a nootropic.
How does Glycine feel?
People who take high quality glycine supplements report better sleep quality, and improved mood during the day.
Some users say they felt more balanced and livelier once they started supplementing with glycine.
Glycine is best taken 60 minutes before bed. Most users report a minimum of 7 hours of undisturbed, high quality sleep.
Glycine helps even chronic insomniacs fall asleep easily.
Unlike most sleep inducers, glycine does not leave you feeling groggy and fatigued in the morning. On the contrary, users wake up feeling rested and ready to tackle the day.
Glycine is a good joint health supplement. Because it aids in cartilage regeneration by enhancing collagen re-synthesis.
Glycine may also provide relief from night sweats for pre-menopausal and menopausal women.
Glycine for schizophrenia
22 schizophrenic patients who were treatment-resistant took part in a double blind, placebo-controlled trial. They were administered 0.8g/kg per day of glycine along with their antipsychotic medication.
Clinical assessments were performed bi-weekly. The group who was administered glycine showed a 24-46% reduction in negative symptoms. [xix]
In another double-blind, placebo-controlled study, 14 medicated patients with chronic schizophrenia were treated with glycine. The results showed a significant improvement in negative symptoms in the group that was given glycine but not in the group given placebo. [xx]
Glycine for sleep
In a randomized placebo-controlled trial, 11 healthy adults were given either 3 grams of glycine or a placebo 1 hour before bed for 2 days. The results indicated quicker sleep onset followed by long, restful sleep.[xxi]
In 2012, another placebo-controlled study recruited healthy adults who were restricted to 25% less sleep than normal. Study subjects were given either a placebo or 3 grams of glycine before bed.
In subjects given glycine, the data showed a significant reduction in fatigue often related to reduced sleep.[xxii]
Glycine for learning and memory
Scientists studied the effects of bioglycin, a biologically active form of glycine in healthy students (mean age 20.7 years), and middle-aged men (mean age, 58.9 years).
The researchers specifically measured attention, memory, and mood using a double-blind, randomized design. [xxiii]
The results indicated that bioglycin significantly improved episodic memory in both the young and middle-aged group. And the middle-aged group also showed a significant improvement in the sustained-attention task.
Experts recommend a Glycine dosage of 0.4 grams per kilogram of body weight (g/kg) twice daily when taking an atypical antipsychotic like Zyprexa and Risperdal.
Many human trials have safely used glycine doses of 1 g (1000 mg) per day for supporting brain health after a stroke. And up to 50 grams per day for schizophrenia.
Most Glycine supplements come in 1000 mg capsules. And the most effective dose is reported to be 3 grams 60 minutes before bed.
Glycine supplements are generally considered non-toxic and safe with few side effects in most people.
However, supplementing with 9 grams or more of Glycine may result in mild gastrointestinal symptoms such as an upset stomach, nausea, loose stools, or vomiting.
Slight sedation is also a possible side effect of taking glycine.
Do not take glycine if you are on the antipsychotic drug Clozaril (clozapine). Unlike other drugs used to treat schizophrenia, glycine appears to decrease the effectiveness of Clozaril in some people.[xxiv]
Do not use glycine if you are suffering from diarrhea, as it may worsen the condition.
Due to lack of sufficient research, glycine should be avoided by breastfeeding and pregnant women unless prescribed by a physician.
Glycine is available in 1000 mg capsules, 500 mg tablets, and as powder.
Look for a Glycine supplement with zero “other ingredients”.
Avoid Glycine supplements containing additives such as silicon dioxide, stearic acid, or magnesium stearate.
Nootropics Expert Recommendation
I recommend Glycine as a nootropic supplement.
Your body makes some Glycine during the day. But you need more Glycine than your body can produce on its own. So, you must get it from food or a nootropic supplement.
Glycine is particularly effective in those dealing with sleep disorders or insomnia.
Supplementing with Glycine should provide a good night’s sleep. And have you feeling well-rested the next morning.
Glycine has been shown to be effective in those dealing with schizophrenia. Even while using most regular medications used with this disorder.
But please, if you are dealing with schizophrenia, check with your doctor before using this nootropic.
Glycine as a nootropic supplement used at recommended dosages is non-toxic and safe for most people with little or no side effects.
3 grams of Glycine seems to be most effective for most people taken about 60 minutes before bed.
[ii] Ballevre O., Cadenhead A., Calder A.G., Rees W.D., Lobley G.E., Fuller M.F., Garlick P.J. “Quantitative partition of threonine oxidation in pigs: effect of dietary threonine.” American Journal of Physiology. 1990 Oct; 259(4 Pt 1): E483-91. (source)
[iii] Meléndez-Hevia, E., De Paz-Lugo, P., Cornish-Bowden, A., & Cárdenas, M. L. (2009). “A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis.” Journal of biosciences, 34(6), 853–872. (Source)
lycine should be avoided by breastfeeding and pregnant women unless prescribed by a physician.
[viii] Kawai, N., Sakai, N., Okuro, M., Karakawa, S., Tsuneyoshi, Y., Kawasaki, N., Takeda, T., Bannai, M., & Nishino, S. (2015). “The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology” : official publication of the American College of Neuropsychopharmacology, 40(6), 1405–1416. (Source)
[ix] Portas, C. M., Bjorvatn, B., & Ursin, R. (2000). “Serotonin and the sleep/wake cycle: special emphasis on microdialysis studies.” Progress in neurobiology, 60(1), 13–35. (Source) lycine should be avoided by breastfeeding and pregnant women unless prescribed by a physician.
[x] Kawai, N., Bannai, M., Seki, S., Koizumi, T., Shinkai, K., Nagao, K., Matsuzawa, D., Takahashi’, M., & Shimizu, E. (2012). “Pharmacokinetics and cerebral distribution of glycine administered to rats. Amino acids, 42(6), 2129–2137. (Source)
[xii] Javitt, D. C., Silipo, G., Cienfuegos, A., Shelley, A. M., Bark, N., Park, M., Lindenmayer, J. P., Suckow, R., & Zukin, S. R. (2001). Adjunctive high-dose glycine in the treatment of schizophrenia. The international journal of neuropsychopharmacology, 4(4), 385–391. (Source)
[xiii] Becquet, D., Hery, M., Francois-Bellan, A. M., Giraud, P., Deprez, P., Faudon, M., Fache, M. P., & Hery, F. (1993). “Glutamate, GABA, glycine and taurine modulate serotonin synthesis and release in rostral and caudal rhombencephalic raphe cells in primary cultures.” Neurochemistry international, 23(3), 269–283. (Source)
[xiv] File, S. E., Fluck, E., & Fernandes, C. (1999). “Beneficial effects of glycine (bioglycin) on memory and attention in young and middle-aged adults.” Journal of clinical psychopharmacology, 19(6), 506–512. (Source)
[xv] Altamura, C., Maes, M., Dai, J., & Meltzer, H. Y. (1995). “Plasma concentrations of excitatory amino acids, serine, glycine, taurine and histidine in major depression.” European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 5 Suppl, 71–75. (Source)
[xvii] Shim, S. S., Hammonds, M. D., & Kee, B. S. (2008). “Potentiation of the NMDA receptor in the treatment of schizophrenia: focused on the glycine site.” European archives of psychiatry and clinical neuroscience, 258(1), 16–27. (Source)
[xviii] Gusev, E. I., Skvortsova, V. I., Dambinova, S. A., Raevskiy, K. S., Alekseev, A. A., Bashkatova, V. G., Kovalenko, A. V., Kudrin, V. S., & Yakovleva, E. V. (2000). Neuroprotective effects of glycine for therapy of acute ischaemic stroke. Cerebrovascular diseases (Basel, Switzerland), 10(1), 49–60. (Source)
[xix] Heresco-Levy, U., Javitt, D. C., Ermilov, M., Mordel, C., Silipo, G., & Lichtenstein, M. (1999). Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia. Archives of general psychiatry, 56(1), 29–36. (Source)
[xx] Javitt, D. C., Zylberman, I., Zukin, S. R., Heresco-Levy, U., & Lindenmayer, J. P. (1994). Amelioration of negative symptoms in schizophrenia by glycine. The American journal of psychiatry, 151(8), 1234–1236. (Source)
[xxi] Yamadera, W., Inagawa, K., Chiba, S., Bannai, M., Takahashi, M. and Nakayama, K., (2016). “Glycine Ingestion Improves Subjective Sleep Quality In Human Volunteers, Correlating With Polysomnographic Changes.” (Source)
[xxii] Bannai, M., Kawai, N., Ono, K., Nakahara, K., & Murakami, N. (2012). “The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers.” Frontiers in neurology, 3, 61. (Source)
[xxiii] File, S. E., Fluck, E., & Fernandes, C. (1999). “Beneficial effects of glycine (bioglycin) on memory and attention in young and middle-aged adults.” Journal of clinical psychopharmacology, 19(6), 506–512. (Source)
[xxiv] Potkin, S. G., Jin, Y., Bunny, B. G., Costa, J., & Gulasekaram, B. (1999). Effect of clozapine and adjunctive high-dose glycine in treatment-resistant schizophrenia. The American journal of psychiatry, 156(1), 145–147. (Source)