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Better Sleep and 7 Other Glycine Benefits

Need to catch some z’s, pronto? Glycine can help with that, according to Louisa Nicola, neurophysiologist and CEO of Neuro Athletics. The celebrity performance coach who works with NFL players like Bryce Butler and NBA players like Omer Stevenson, swears by glycine—an amino acid—to help her (and her clients) get better sleep.

Nicola takes glycine as a part of her daily sleep stack, along with other compounds that she says have demonstrated relaxation-promoting and stress-relieving properties like magnesium L-threonate, GABA, and ashwagandha.

“Glycine has a powerful effect on sleep,” says Nicola. “And sleep is crucial to maintaining physical, cognitive, and emotional health.” A lack of solid sleep has been linked to a host of health issues, including obesity, diabetes, cardiovascular disease, poor immunity, poor mental health, and neurodegeneration. It can also lead to accidents on the road and in the workplace.

But better shut-eye is just the tip of the iceberg when it comes to glycine benefits. Here’s everything you need to know about glycine, and why you might want to consider adding it to your supplement stack.

What Is Glycine?

“Glycine is one of the twenty amino acids that serves as a building block for protein synthesis in living organisms,” says Nicola. It’s a component of several proteins that play key roles in muscle maintenance and hormone regulation.

Glycine is produced naturally in the body (that’s why it’s called a non-essential amino acid). In other words, you technically don’t need to eat glycine or take a glycine supplement, since your body can produce it on its own. “While the body can produce glycine, this doesn’t negate the potential benefits of external supplementation, particularly for individuals whose natural synthesis may not be adequate for optimal physiological functioning,” says Nicola.

The average person gets about 1.5 to three grams of glycine per day from rice or other protein-rich foods like meat and fish, which is in the ballpark of the three grams Nicola recommends for sleep benefits (1).

8 Surprising Glycine Benefits

For a *non-essential* amino acid, the benefits of glycine are impressive.

Improves sleep quality

Nicola isn’t the only one who’s experienced better sleep thanks to glycine. “In one study, 15 healthy participants aged between 24 and 53 years who reported chronic sleep dissatisfaction, experienced a reduced feeling of fatigue when administered three grams of glycine within one hour before bedtime (2),” says Nicola.

Another found that in subjects continuously experiencing poor sleep quality, taking three grams of glycine before bedtime reduced the time it took to fall asleep, improved sleep efficiency, and decreased daytime sleepiness when compared to a placebo (3).

There are two ways glycine may affect sleep: “Glycine’s sleep-promoting mechanisms are thought to involve a reduction in core body temperature and the modulation of serotonin levels,” explains Nicola.

Researchers suspect by increasing the supply of serotonin in the prefrontal cortex (the part of the brain involved in memory consolidation during sleep), glycine may indirectly affect melatonin production (4, 5).

“Since adding glycine to my nightly routine, I’ve observed a measurable improvement in sleep quality, supported by Oura ring data. I’ve seen an average increase of 12 to 15 minutes in deep sleep and a 5- to 7-point rise in my Readiness Score,” says Nicola. “Subjectively, I fall asleep more quickly and wake up feeling more refreshed. These changes are consistent with glycine’s known effects on enhancing deep sleep and improving sleep onset latency.”

Supports memory and mood

Glycine stimulates the production of serotonin—aka the “feel good” hormone. Serotonin can help elevate mood, improve sleep, and enhance memory and thinking.

“Glycine also acts as a neurotransmitter in the central nervous system,” says Nicola. Meaning: it helps your brain process motor and sensory information (6). Glycine specifically acts on N-methyl-D-aspartate (NMDA) receptors to produce an excitatory effect—a process that has been linked to building neuroplasticity, learning, and memory (7).

Protects against muscle loss

As a key component of collagen, glycine helps provide structure and strength to bones, skin, muscles, and connective tissues. Researchers believe that collagen peaks around age 25 to 34 years, and then begins to decline. To start, you might notice changes like less skin elasticity and more fragile hair strands (8). By the time you’re in your sixties, you might be looking at deeper wrinkles and significant loss of muscle mass.

Glycine might also help preserve muscle under common conditions of muscle wasting such as aging, malnutrition, or situations where your body is under a lot of stress like cancer (9).

Serves as an essential component of creatine

Glycine is one of three amino acids your body needs to make creatine—which helps your body create ATP, a source of energy used by your muscles and brain. When combined with resistance training, creatine has been shown to increase muscle size and strength (10). Interestingly, supplementing with creatine may improve short-term memory, intelligence, reasoning, and memory (11, 12). While your body naturally produces creatine, getting too little glycine may reduce how much you produce (13).

Reduces inflammation

Low-grade inflammation can be a common culprit behind the scenes of many chronic diseases—everything from erectile dysfunction to heart disease. Glycine to the rescue: “It has a broad spectrum of anti-inflammatory, cytoprotective, and immunomodulatory properties,” according to a review published in Mini-Reviews in Medicinal Chemistry (14).

Boosts immune function

Glycine is one of three amino acids your body needs to produce glutathione. As your body’s “master antioxidant” and a maestro of the immune system, glutathione has a few big jobs in your body. The main one: to fight against free radicals, the unstable molecules that can damage your cells and cause oxidative stress (15).

Left unchecked, oxidative stress can contribute to a smorgasbord of health conditions and chronic diseases including diabetes, cancer, cardiovascular disease, Alzheimer’s, kidney disease, and more. Without enough glycine, your body produces less glutathione, which could negatively affect how your body handles oxidative stress over time (16).

Increases insulin sensitivity

Insulin resistance is a common hallmark of type 2 diabetes, but one study found that glycine might increase insulin response (17). What’s more higher levels of glycine are associated with a reduced risk of type 2 diabetes, even after accounting for other lifestyle factors (18, 19).

Protects your heart

In a study of 4,109 people with chest pain, researchers found that those with higher plasma glycine levels had a more favorable heart disease risk profile and a decreased risk of heart attack at a 7.4-year follow-up (20). Glycine was specifically linked to improved low-density lipoprotein (LDL) cholesterol levels, as well as apolipoprotein B (ApoB). ApoB is the main protein found in the “bad” LDL cholesterol and can be used to determine heart disease risk.

Get More Glycine

Want more glycine? “While glycine supplementation has its merits, particularly for sleep, I also advocate for the consumption of glycine-rich foods for comprehensive health benefits,” says Nicola. Glycine-rich foods include protein-heavy foods like legumes, fish, dairy, and meat; as well as rice and seeds (21).

If you prefer the supplement route, you can take glycine at any time of day, but to avoid drowsiness, best to take no more than one gram. However, Nicola recommends taking three grams around an hour before you go to bed since this dosage is consistent with the protocols used in clinical studies that demonstrate sleep benefits. Glycine can be found in powder or capsule form. The powder easily dissolves in water and is naturally sweet which makes it a great candidate for adding to coffee, tea, protein shakes, or oatmeal.

Downsides of Supplementing With Glycine

When taken in normal amounts, glycine is generally considered safe. However, there’s little research on its long-term use, so it’s best to consult your doctor before giving it a shot. High amounts of glycine can be toxic. Signs of glycine toxicity include vomiting, weakness, drowsiness, visual disturbances, prickling skin sensations, and gastrointestinal distress (22, 23).

1. Alves, A. et al (2019). Glycine Metabolism and Its Alterations in Obesity and Metabolic Diseases.
2. Inagawa, K. et al (2006). Subjective Effects of Glycine Ingestion Before Bedtime on Sleep Quality.
3. Yamadera, W. et al (2007). Glycine Ingestion Improves Subjective Sleep Quality in Human Volunteers, Correlating With Polysomnographic Changes.
4. Kawai, N. et al (2015). The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus.
5. Banai, M. et al (2011). Oral Administration of Glycine in Increases Extracellular Serotonin but Not Dopamine in the Prefrontal Cortex of Rats.
6. Lopez-Corcuera, B. et al (2001). Glycine Neurotransmitter Transporters: An Update. 
7. Bartolomeis, A. et al (2020). Glycine Signaling in teh Framework of Dopamine-Glutamate Interaction and Postsynaptic Density. Implications for Treatment-Resistant Schizophrenia.
8. Reilly, D. et al (2021). Skin Collagen Through the Lifestages: Importance for Skin Health and Beauty.
9. Koopman, R. et al (2017). Glycine Metabolism in Skeletal Muscle: Implications for Metabolic Homeostasis.
10. Chilibeck, P. et al (2017). Effect of Creatine Supplementation During Resistance Training on Lean Tissue Mass and Muscular Strength in Older Adults: A Meta-Analysis.
11. Avgerinos, K. et al (2019). Effects of Creatine Supplementation on Cognitive Function of Healthy Individuals: A Systematic Review of Randomized Controlled Trials.
12. Prokopidis, K. et al (2023). Effects of Creatine Supplementation on Memory in Healthy Individuals: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
13. Kalhan, S. et al (2017). Whole Body Creatine and Protein Kinetics in Healthy Men and Women: Effects of Creatine and Amino Acid Supplementation.
14. Perez-Torres, I. et al (2017). Beneficial Effects of the Amino Acid Glycine.
15. Liguori, I. et al (2018). Oxidative Stress, Aging, and Diseases.
16. McCarty M. et al (2018). Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection.
17. Yan-Do, et al (2016). A Glycine-Insulin Autocrine Feedback Loop Enhances Insulin Secretion From Human β-Cells and Is Impaired in Type 2 Diabetes.
18. Adeva-Andany, M. et al (2018). Insulin Resistance and Glycine Metabolism in Humans.
19. Lustgarten, M. et al (2013). Serum Glycine Is Associated with Regional Body Fat and Insulin Resistance in Functionally-Limited Older Adults.
20. Ding, Y. et al (2016). Plasma Glycine and Risk of Acute Myocardial Infarction in Patients With Suspected Stable Angina Pectoris.
21. Razak, M. et al (2017). Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review.
22. Inagawa, K. et al (2006). Assessment of Acute Adverse Events in Glycine Ingestion at a High Dose in Human Volunteers.
23. Heresco-Levy, U. et al (1999). Efficacy of High-Dose Glycine in the Treatment of Enduring Negative Symptoms of Schizophrenia.