Glycine Benefits: From Sleep to Physical Performance

Glycine Benefits: From Sleep to Physical Performance

Authored by Brady Holmer • 
November 11, 2019
 • 7 min read
supplementsnutritionfitnessnootropics

Interested in taking your performance, health, and sleep to the next level? Maybe you’ve experimented with multiple supplements and are now looking for something novel to enhance your output. One tiny amino acid—with not so tiny effects, may be able to give you a boost.

This awesome amino acid is glycine. We can’t live without it. And, while it’s in many of the foods we eat, you probably still aren’t getting as much as you need. The effects of glycine, while understudied, may also be of interest to those wishing to enhance cognitive and physical performance.

A Pretty Sweet Molecule

We usually think of amino acids as they relate to protein: the building blocks of muscle that bodybuilders take to get lean gains and increase mass. Besides muscle growth, dietary amino acids play a number of vital roles throughout the rest of the body, and glycine plays several particularly important parts.

Glycine is the simplest amino acid (in structure, at least). Its name comes from the Greek for “sweet” (glykys), since it has been described as being as sweet in taste–like glucose. Glycine is a non-essential amino acid. So, while we do ingest a certain amount of dietary glycine, our body can also can synthesize its own.

Glycine made in the body is used in collagen synthesis.

Let's pause for a moment to discuss the benefits of collagen. It's essential for maintaining the structure of tissues, joints and blood vessels. It also promotes healthy skin, hair, and nails. But you probably aren't getting enough collagen, and with age, the body's natural collagen production begins to decline.

A healthy body requires proper collagen synthesis and composition. It is, quite literally, what we’re made of. Without enough glycine, collagen production suffers.

Other activities of glycine include its important role in the production of heme (a protein found in blood), creatine, and several antioxidants. Glycine is also integrated into enzymes, giving them flexibility to bend, twist, and interact with energy-producing substrates in our body.

While technically “non-essential,” the amounts of glycine we synthesize plus dietary glycine may fall short of the amount we need for optimal metabolic function. 15 grams is about what we need each day for all of the above metabolic functions to occur. But, we make only around 2.5 grams per day! This leaves another 12 grams of glycine intake needed to function at our best, and studies indicate that other sources (like dietary glycine) probably don’t meet this need.1

Maximum growth and collagen synthesis (at least in animals) can’t be achieved through the body’s own glycine synthesis pathways.2 Glycine supplementation is one way to bump up your levels and reap the health benefits glycine has to offer.

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Health and Wellness Benefits of Glycine

Glycine deficiency isn’t life threatening, but low amounts of glycine intake will short-change synthesis of important enzymes and proteins–this could have detrimental effects on health.

Low glycine status means you’ll limit your ability to make collagen and connective tissue for bones, skin, hair, and nails. Glutathione synthesis proceeds glycine, so lower amounts of glycine (or its antioxidant product) could lead to down-regulation of antioxidants and a general state of immune system inflammation. The result? Oxidative stress, an environment associated with negative health problems like the metabolic syndrome.

Don’t worry about a glycine overdose. The safety of glycine supplementation has been confirmed at doses of 0.5g/Kg of body weight for eight weeks, 0.8g/Kg for six weeks, and even the same 0.8g/Kg dose for up to five years! Not only is it safe, but glycine supplementation has been shown to yield numerous health benefits.

Brain Food

Is your cortex in need of a little pick-me-up? Since glycine plays an important role in central nervous system neurotransmission (brain signalling), some believe that boosting glycine levels may actually lead to lower levels of negative mental states, improve cognition and positive mood, and perhaps be useful for memory loss.3

While this hasn’t been formally tested in research studies of healthy people, it has been used to treat symptoms of schizophrenia, with promising results.4 Similar to GABA, glycine is an inhibitory neurotransmitter that may help to quell an over-stimulated brain state and reduce stress and manic-like brain activity. The benefits of glycine supplementation likely come from positive effects on these and other neurotransmitter levels. This means better communication among your neurons.

Your Heart Loves Glycine

Cardiovascular health benefits of glycine have also been observed. Having a higher plasma concentration of glycine is associated with favorable levels of blood fatty acids in men and women, lower blood pressure and risk of type 2 diabetes, and fewer risk factors for suffering a heart attack or ischemic stroke.5 While these are only associations, a pattern seems to emerge.

People who have higher levels of glycine have seem to have a certain level of protection against diseases of the heart.

Higher glycine and lower cardiovascular risk could be due to the known benefits of glycine on inflammation and lipid metabolism. It’s anti-atherogenic, meaning it protects against the narrowing of arteries and other disease-processes. Feeding a glycine-rich diet has been shown to reduce platelet aggregation—a mechanism involved in heart attacks and CVD risk. Treatment with glycine has even been shown to protect against the harmful vascular effects of a high sugar “western diet” (mice, meet McDonalds).6

A Metabolic Boost

Glycine may also benefit metabolic health. Higher serum levels of glycine are associated with a lower amount of insulin resistance, better insulin sensitivity and less abdominal fat;7 a risk factor related to metabolic disorders.

Studies show that consuming 5g of glycine in the morning enhances insulin secretion throughout the day in individuals predisposed to type 2 diabetes.8 Insulin secretion and proper insulin sensitivity is needed for the efficient uptake of glucose; glycine might aid in this process. Furthermore a glycine supplementation, along with ingestion of glucose, slices the rise in blood sugar in half compared to glucose alone.9

Better glucose regulation has profound health benefits for everyone, not just diabetics. An ability to better regulate blood sugar levels throughout the day can benefit your mental and physical performance. Avoid the sugar crash!

Down with Inflammation

Lowering inflammation and oxidative stress has numerous benefits including everything from disease prevention to increased mental health and performance. Here, glycine intake may help, since it has been shown to protect against oxidative stress-related damage caused by free radicals. Glycine inhibits the production of toxic inflammatory molecules like tumor necrosis factor (TNF) and oxygen free radicals in the lungs,10 and has even been shown to reduce oxidative stress following liver injury, ischemic stroke, and heart attacks.

These profound benefits occur largely because glycine is a dietary precursor to a potent antioxidant molecule called glutathione. Glutathione neutralizes damage causing free radicals and lowers oxidative stress.

Boosting glycine levels will enhance glutathione synthesis. Just 20 days of supplementing with glycine reduces pro-inflammatory gene expression. The beneficial effects of glycine supplementation were shown by increased antioxidant levels of glutathione by 94.6%. Glycine also dramatically lowered inflammatory factors in aging individuals with high levels of oxidative stress (who were glycine-deficient).11

Health and wellness benefits of glycine.

Glycine for Athletes

Always looking to gain a competitive edge, certain athletes could potentially benefit from supplementing with glycine. Could you?

Peak Performance

First, let’s talk about gains–muscle gains. Experiments have shown that taking a single bolus with a high dose (22.5 grams) of glycine caused a 60% surge in growth hormone release from the pituitary gland in under five minutes.12 A rapid growth hormone boost post-workout will help stimulate protein synthesis, build muscle, and promote recovery for the next workout.

Smaller doses of four, eight, and, twelve grams also increases serum levels of growth hormones in a dose-dependent manner.13

While yet to be confirmed in athletes, there may be a potential for glycine to augment adaptations to strength training.

What about anaerobic performance? On its own, glycine hasn’t been studied much in this area. However, a supplemental form of glycine known as glycine-propionyl-L-carnitine (GPLC) has been shown to enhance peak power production and reduce the amount of lactate build up during repeated, high-intensity sprints when taken just 90 minutes before exercise.14 The same boost in peak power was shown with longer-term supplementation of this compound for 28 days.15 Does your sport or activity involve heavy-intensity intervals? Glycine-containing supplements could help you rock the next set.

Recover Better

If you’re injured, it’s safe to say performance output won’t matter much. You have to stay healthy.

Interestingly, glycine and green tea has proven to be effective in recovery after injury–the combination could could get you back on the field or the track sooner. Mice with achilles tendinitis which were given a glycine and green tea cocktail had greater tissue recovery, more collagen synthesis, and lower inflammation.16 The combination of these two supplements produced a faster and more salient remodeling process after injury.17 Glycine may perhaps be an under-appreciated recovery aid.

Athletic performance benefits of glycine.

Sweet Dreams: How Glycine Benefits Sleep

Everyone needs close to ideal sleep quality and quantity to perform at their best, mentally, physically, and emotionally. Without adequate restful sleep, good luck climbing to the top of the ladder at work, your rec basketball league, or your weekly pub trivia night.

Glycine can help get you the rest needed to achieve. Using the gold standard-measure of sleep, polysomnography (PSG), researcher shows 3g of glycine ingester before bed reduces time to fall asleep (known as sleep latency) and helps people get into restorative, growth-inducing, recovery-promoting slow-wave sleep (SWS) faster.18

A good night of sleep means better performance the next day.

Objective measures of sleep quality–fatigue, liveliness, peppiness, and clear-headedness—all improve the next day following a glycine-induced slumber. Glycine even reduces daytime sleepiness and improves psychomotor performance when sleep restriction is forced to be 25% less than normal for up to three nights.19

For athletes, sleep is a pillar of performance. Reduced endurance performance, lower strength, and poor psychomotor function–these are just a few impacts of inadequate sleep in athletes.20 Glycine as a sleep-promoting nutritional supplement is well supported and is worth exploring. In fact, the arena of sleep is where glycine has shown promise as a nutritional aid.

In times when you’re short on sleep, glycine could be protective against daytime sleepiness and keep you on your A game.

Sleep quality enhancing benefits of glycine can be easily obtained by using supplements, especially sleep aids containing 500mg of L-glycine along with melatonin, L-theanine, and magnesium glycinate. Together, these ingredients combine to help the body and the brain get into recharge mode and kick butt the next day. Clinical studies have shown that the supplements containing the aforementioned components can reduce the time to fall asleep by seven minutes and increase sleep efficiency by 3%.21,22,23

No more counting sheep. Give supplemental glycine and nootropics a try to prioritize your sleep hygiene. As one of the pillars of physical and mental performance, this area of human health and optimization can’t be ignored. Dream on.

Glycine benefits sleep.

An All-Around Supplement

With a key role in so many bodily processes (from brain function to healthy skin and nails), glycine is one amino acid that, while “non-essential,” is truly “essential” take your body and mind to the next level. Even better, when reasonable amounts of glycine are used as a supplement, there seem to be few side effects, other than mild GI distress.

Adding this supplement to your diet might level up your game and help take performance to the next level.

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Scientific Citations

1.Meléndez-hevia E, De paz-lugo P, Cornish-bowden A, Cárdenas ML. A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis. J Biosci. 2009;34(6):853-72.
2.Li P, Wu G. Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth. Amino Acids. 2018;50(1):29-38.
3.Imtiaz S, Ikram H, Ayaz M, Qadir MI, Muhammad SA. Effect of glycine: Studying memory and behavioral changes in mice. Pak J Pharm Sci. 2018;31(5):1943-1949.
4.Heresco-levy U, Ermilov M, Lichtenberg P, Bar G, Javitt DC. High-dose glycine added to olanzapine and risperidone for the treatment of schizophrenia. Biol Psychiatry. 2004;55(2):165-71.
5.Ding Y, Svingen GF, Pedersen ER, et al. Plasma Glycine and Risk of Acute Myocardial Infarction in Patients With Suspected Stable Angina Pectoris. J Am Heart Assoc. 2015;5(1)
6.El hafidi M, Pérez I, Zamora J, Soto V, Carvajal-sandoval G, Baños G. Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats. Am J Physiol Regul Integr Comp Physiol. 2004;287(6):R1387-93.
7.Lustgarten MS, Price LL, Phillips EM, Fielding RA. Serum glycine is associated with regional body fat and insulin resistance in functionally-limited older adults. PLoS ONE. 2013;8(12):e84034.
8.González-ortiz M, Medina-santillán R, Martínez-abundis E, Von drateln CR. Effect of glycine on insulin secretion and action in healthy first-degree relatives of type 2 diabetes mellitus patients. Horm Metab Res. 2001;33(6):358-60.
9.Gannon MC, Nuttall JA, Nuttall FQ. The metabolic response to ingested glycine. Am J Clin Nutr. 2002;76(6):1302-7.
10.Wheeler MD, Thurman RG. Production of superoxide and TNF-alpha from alveolar macrophages is blunted by glycine. Am J Physiol. 1999;277(5):L952-9.
11.Sekhar RV, Patel SG, Guthikonda AP, et al. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr. 2011;94(3):847-53.
12.Kasai K, Kobayashi M, Shimoda SI. Stimulatory effect of glycine on human growth hormone secretion. Metab Clin Exp. 1978;27(2):201-8.
13.Kasai K, Suzuki H, Nakamura T, Shiina H, Shimoda SI. Glycine stimulated growth hormone release in man. Acta Endocrinol. 1980;93(3):283-6.
14.Jacobs PL, Goldstein ER, Blackburn W, Orem I, Hughes JJ. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr. 2009;6:9.
15.Jacobs PL, Goldstein ER. Long-term glycine propionyl-l-carnitine supplemention and paradoxical effects on repeated anaerobic sprint performance. J Int Soc Sports Nutr. 2010;7:35.
16.Vieira CP, De oliveira LP, Da ré guerra F, Marcondes MC, Pimentel ER. Green Tea and Glycine Modulate the Activity of Metalloproteinases and Collagen in the Tendinitis of the Myotendinous Junction of the Achilles Tendon. Anat Rec (Hoboken). 2016;299(7):918-28.
17.Vieira CP, Guerra Fda R, De oliveira LP, Almeida MS, Marcondes MC, Pimentell ER. Green tea and glycine aid in the recovery of tendinitis of the Achilles tendon of rats. Connect Tissue Res. 2015;56(1):50-8.
18.Yamadera W, Inagawa K, Chiba S, et al. Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms. 2007; 5 (2), 126-131
19.Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. J Pharmacol Sci. 2012;118(2):145-8.
20.Halson SL. Sleep in elite athletes and nutritional interventions to enhance sleep. Sports Med. 2014;44 Suppl 1:S13-23.
21.Ferracioli-oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS ONE. 2013;8(5):e63773.
22.Brzezinski A, Vangel MG, Wurtman RJ, Norrie G, Zhdanova I, Ben-Shushan A, Ford I. Effects of exogenous melatonin on sleep: a meta-analysis. Sleep Med Rev. 2005 Feb;9(1):41-50.
23.Inagawa K, Hiraoka T, Kohda T, Yamadera W, Takahashi M. Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms. 2006; 4 (1), 75-77
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© 2019 HVMN Inc. All Rights Reserved. H.V.M.N.®, Health Via Modern Nutrition™, Nootrobox®, Rise™, Sprint®, Yawn®, Kado™, and GO Cubes® are registered trademarks of HVMN Inc. ΔG® is a trademark of TΔS® and used under exclusive license by HVMN Inc.