Glycine is a proteinogenic amino acid, which means it is among the amino acids used as building blocks for proteins. It is the simplest (and smallest) amino acid. Glycine benefits include improvements to fatigue, skin health, mental health, and inflammation.

What Does Glycine Do?

Glycine‘s numerous benefits make it attractive as a supplement. Glycine has a calming effect in the brain which helps promote sleep. It also helps to lower your body temperature at night which makes sleep more restful [1]. In addition, glycine benefits a reduction in skin wrinkles and suppresses UV-B-induced skin damage and photoaging [2]. It has also been known to help in the treatment of obsessive-compulsive disorder [3] and schizophrenia [4].

Glycine Benefits Sleep

One of the most popular reasons people turn to glycine is because of its impact on sleep. When we absorb glycine ingested orally, it increases serotonin levels without increasing dopamine levels. This helps normalize circadian rhythms, creating a better sleep routine in your body [5].

Glycine Benefits Sleep Quality

When glycine diffuses through the blood-brain barrier, it acts primarily on NMDA receptors. The actions are thought to help inhibit muscle activity during the REM stages of sleep and lower core body temperatures [1]. Both of these effects result in deeper, more restful sleep.

Glycine Decreases Fatigue

While glycine doesn’t actually decrease fatigue, glycine benefits your sleep patterns, making sleep more effective help reduce patterns of fatigue. It also helps you feel more rested on less sleep since your sleep is more effective.

In a study published by the Sleep and Biological Rhythms Society, researchers found that glycine produced an improved feelings of clear-headedness and liveliness after consuming glycine before bedtime [6].

In a second study, researchers evaluated volunteers after 3 nights of sleep deprivation. The participants in the study had their sleep reduced by nearly 2 hours per night for 3 consecutive nights. Those who took glycine before had significantly less fatigue, less daytime sleepiness, and higher daytime performance than those who ingested a placebo [7].

Glycine Benefits Memory and Learning

Glycine benefits memory and learning in the face of neurodegeneration [8]. It is involved in signaling through the hippocampus. It also exerts a neuroprotective effect against the neuroapoptosis, neuroinflammation, synaptic dysfunction, and memory impairment resulting from elevated oxidative stress in the brain [8].

Glycine Benefits Those in Treatment for Mental Illness

Researchers have seen positive effects when those with obsessive-compulsive disorder [9], body dysmorphic disorder [3], and schizophrenia [4] supplement with glycine during treatment.

It may also help reduce effects of depression, especially if you have low glycine levels. Depression is associated with low glycine levels as well as high taurine levels [10].

Glycine May Reduce Wrinkles

While glycine’s biggest claim to fame has been its effects on sleep, it’s second most renown effects are on skin health. Glycine benefits skin elasticity, and moisture and water retention. Women who took a glycine-based supplement for 4 weeks saw eye wrinkles reduce by 20%, with positive effects lasting after the study ended [11]. At 8 weeks, collagen had improved procollagen type 1 by 65% and elastin by 8% [11].

When Should I Take Glycine?

We recommend taking glycine with food before bed. Taking glycine on an empty stomach can sometimes cause nausea. Because of glycine’s benefits related to sleep preparation, it’s more helpful before bed than in the morning or midday.

While most people don’t experience side effects, many nutritional experts recommend starting slowly. Try 1 gram before bed for several days, then increase the dose incrementally if you do not experience any results. As always, we strongly suggest speaking with your doctor before starting supplementation or changing doses.

If you would like to purchase a high-quality glycine supplement, look no further than Metabolic Maintenance’s Glycine Powder, available here.

*The information in this article has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

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  1. Kawai, Nobuhiro, et al. “The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus.” Neuropsychopharmacology 40.6 (2015): 1405-1416.
  2. Juliana, Cendy, et al. “Antioxidant and elastase inhibitor from black soybean (Glycine max L.) and its compound (daidzein).” Journal of Biomedicine and Translational Research 6.1 (2020): 11-14.
  3. Cleveland, W. Louis, et al. “High-dose glycine treatment of refractory obsessive-compulsive disorder and body dysmorphic disorder in a 5-year period.” Neural plasticity 2009 (2009).
  4. Heresco-Levy, Uriel et al. “High-dose glycine added to olanzapine and risperidone for the treatment of schizophrenia.” Biological psychiatry vol. 55,2 (2004): 165-71. doi:10.1016/s0006-3223(03)00707-8
  5. Bannai, Makoto, et al. “Oral administration of glycine increases extracellular serotonin but not dopamine in the prefrontal cortex of rats.” Psychiatry and Clinical Neurosciences 65.2 (2011): 142-149.
  6. Inagawa, Kentaro, et al. “Subjective effects of glycine ingestion before bedtime on sleep quality.” Sleep and Biological Rhythms 4.1 (2006): 75-77
  7. Bannai, Makoto, et al. “The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers.” Frontiers in neurology 3 (2012): 61.
  8. Ullah, Rahat, et al. “Glycine, the smallest amino acid, confers neuroprotection against D-galactose-induced neurodegeneration and memory impairment by regulating c-Jun N-terminal kinase in the mouse brain.” Journal of Neuroinflammation 17.1 (2020): 1-21.
  9. Greenberg, William M., et al. “Adjunctive glycine in the treatment of obsessive-compulsive disorder in adults.” Journal of psychiatric research 43.6 (2009): 664-670.
  10. Hung, Ching-I., et al. “Metabolomics-based discrimination of patients with remitted depression from healthy controls using 1H-NMR spectroscopy.” Scientific reports 11.1 (2021): 1-8.
  11. Proksch, Ehrhardt, et al. “Oral intake of specific bioactive collagen peptides reduces skin wrinkles and increases dermal matrix synthesis.” Skin pharmacology and physiology 27.3 (2014): 113-119.