November 20, 2023 9 min read

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    In case glycine doesn’t, the term amino acids probably rings a bell. These powerful molecules are the building blocks of protein, and the importance of protein remains a prominent, well-researched topic. However, when it comes to individual amino acids and their specific roles, it is safe to say that these compounds don’t often receive the much-needed attention.

    In this comprehensive yet simplified article, we'll help you navigate the science, simplicity, and practicality of this overlooked amino. We’ll dive into its complex roles, numerous benefits, and most abundant sources. Plus, we got those protips and hot hacks we know you love, so let's dive in! 

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    Glycine - The Backstory on this Sweeeet Amino Acid

    From enhanced sleep quality to a fortified shield against oxidative stress, from joint and vascular health to cognitive rejuvenation, glycine is a treasure trove of wellness, and collagen provides ample amounts of this previously underrated nutrient.  

    Discovered in 1820 by the French chemist Henri Braconnot, glycine has humble beginnings. This amino acid's name, derived from the Greek word "glykys," meaning sweet, reflects its sweet taste. Some “old-school” bodybuilders may even recall using glycine as a low-calorie sweetener. 

    While we feel supplementation of glycine on its own isn’t necessary for most people since it is common in most high-protein foods, and especially our most abundant protein - collagen (which everyone seems to be taking these days!), it is an interesting option over artificial sweeteners, for those who feel they may benefit from a little extra of this amino acid. 

    Glycine is the body's most important nonessential amino acid, comprising 11.5% of total amino acids, with 80% being used for protein synthesis - primarily in connective tissues, like collagen. 

    Pro-tip:Whether you take glycine or collagen to boost your connective tissue health, combining it withvitamin C can enhance the results since itboosts collagen production. This is why scurvy causes bleeding gums, due to the collagen deficiency it allows. Make sure your vitamin C is unheated because heat denatures it.  

    Despite being required in large amounts, glycine has long been considered a non-essential amino acid because our bodies have the ability to synthesize it from three other amino acids: serine, proline, and threonine, as well as from choline. However, it's now well established that our bodies cannot make enough to replace the need for some dietary intake in humans completely, and in many cases, our need goes up, such as during rapid growth and pregnancy or after injury or surgery.

    Glycine for Recovery after Injury

    In fact, recent research shows that collagen synthesis is often greatly diminished in osteoarthritis, which requires large amounts of glycine, proline, and lysine, all of which are found in protein foods, but especially collagen supplements. Since glutathione is also typically low in osteoarthritis, increasing glycine intake, and protein in general, could also help in this regard. 

    Glycine has many more important functions, such as synthesizing glutathione, purines, heme (as part of hemoglobin for oxygen transport), glucose (during a shortage), creatine, porphyrins, RNA, DNA, serine, and more. It is necessary for bile acid conjugation in the gallbladder, thus indirectly facilitating digestion and absorption of fats, lipid-soluble vitamins, and cholesterol. 

    So, while small shortages of glycine are not harmful, severe shortages can lead to poor immunity, growth, nutrient metabolism, and cytoprotection. 

    The Marvelous Benefits of Glycine

    As you can see, glycine, the "unsung hero" of amino acids, offers many benefits. Let's delve deeper into its roles and specific functions in different areas of our well-being.

    Improved Sleep Quality, Neural Regulation, and Cognitive Health 

    Glycine is an amino acid and neurotransmitter and can play both stimulatory and depressant roles in the brain. As a central nervous system mediator, glycine helps regulate nerve impulses by acting as an NMDA co-agonist, meaning it activates these receptors in the brain, which could explain its helpfulness for some cases of schizophrenia and support sleep quality, which it is commonly used for. 

    It also plays a vital role in memory formation, helps to regulate food intake and body homeostasis, modulates behavior, regulates immune function, produces superoxide, and synthesizes cytokines. 

    Glycine supports serotonin synthesis, which further contributes to its many brain functions and to glycine's sleep portfolio since serotonin is converted to everyone's favorite nighttime molecule, melatonin, as soon as the lights go out. In addition, serotonin has been shown to help reduce stress and anxiety and may even mitigate food cravings,  particularly for sweets. Sign me up! 

    Sleep-Enhancing Effect

    Other sleep-enhancing benefits include slightly reducing body temperature, increasing non-rapid eye movement, and enhancing optimal circadian rhythms. In today's fast-paced world, sleep quality can often be compromised. Glycine, with its unique ability to act as both a stimulant and depressant in the brain, has the power to enhance your sleep. By incorporating glycine into your daily routine, you can experience a more restful and rejuvenating slumber, ensuring you wake up refreshed and ready to conquer the day.

    Pro-tip:A great way to do this is simply having some naturally glycine-rich collagen before bed, either straight up or incorporated into delicious recipes, like homemadejello shots, your nighttimehot chocolate, or your favoritesmoothie recipe

    The Antioxidant Powerhouse - Glutathione from Glycine

    Another of glycine's standout features, along with the other amino acids cysteine and glutamine, is its role in creating the potent antioxidant glutathione. This antioxidant is like a shield that guards your cells against oxidative damage caused by free radicals and regenerates other antioxidants, such as vitamins C and E when depleted. 

    With glycine, your body can produce more glutathione, providing a powerful defense against diseases that have oxidative stress at their core. As you age, your body's natural glutathione levels decline, making glycine intake even more critical for maintaining health.

    Liposomal Glutathione

    Pro-tip:To boost glutathione production further, take your glycine or collagen with some N-acetyl cysteine, another awesome amino! Add some curcumin, milk thistle, or selenium for an extra hit. 

    A Key Ingredient in Creatine Synthesis

    Glycine is crucial in synthesizing creatine, which provides energy for short bursts of intense physical activity, such as weightlifting and sprinting

    Combining glycine or collagen with creatine supplementation around your resistance training can increase muscle size, strength, and power. Additionally, creatine has been explored for its benefits in bone health, brain function, and neurological conditions like Parkinson's and Alzheimer's.

    While humans make some creatine, research shows that a little extra is better for capturing its many health benefits, so supplementing may be useful if you are not eating creatine-rich foods. If you are not using creatine for explosive sports, however, the good news is a little goes a long way. 

    Unveiling the Recent Neuroprotective Research

    Glycine has emerged as a powerful shield against oxidative stress, neurodegeneration, neuroapoptosis, neuroinflammation, synaptic dysfunction, and memory impairment, particularly when induced by elevated reactive oxygen species (ROS) in the brain.

    However, glycine curtails oxidative stress and significantly enhances the expression of antioxidant proteins like Nrf2 and HO-1, often suppressed in neurodegenerative conditions. These benefits hold exciting therapeutic potential for helping prevent cognitive decline for many. 

    Glycine and Cognitive Functions

    Hypertension, Stroke, and Liver Protection

    Several studies have shown inverse correlations between glycine and obesity, diabetes mellitus, and hypertension, and this shows promise for vascular and arterial health via various mechanisms. 

    Firstly, hypertension involves blood vessel elasticity thanks to another glycine-dependent connective protein, elastin, which allows blood vessels to expand and contract. However, low glycine impairs elastin production, particularly in the aorta, which can contribute to hypertension. 

    Secondly, glycine is utilized to break down S-adenosylmethionine, excess concentration of which is linked to apolipoprotein B expression and very low-density lipoprotein formation, with disturbances in these reactions being linked to lipid accumulation in the liver as well as macrophages, which in turn promote foam cell formation in the artery wall, causing damage there. 

    Perhaps this is why participants of a Japanese study with higher intakes of glutamic acid and glycine had significantly decreased mortality from strokes. It might also explain why some doctors prescribe glycine after ischemic stroke to help clear blocked arteries in the brain and regulate glucose metabolism, reducing inflammation and clearing dead cells. However, the research here is a little conflicting.

    Lastly, there's metabolic health, which is strongly linked with hypertension. These studies showed glycines' ability to stabilize blood sugar levels after eating a high fructose or sucrose meal, while others found it was extremely effective at protecting against alcohol-induced hepatotoxicity (liver poisoning) due to glycines' ability to reduce gastric emptying of ethanol, optimize liver enzymes, and reduce ethanol-induced toxicity. 

    How to Incorporate Glycine into Your Regimen

    Dietary Protein as a Source of Glycine

    Well, the good news is, you are already consuming enough glycine in your diet if you are eating sufficient protein, and most definitely if you are already taking collagen, which is around 20% glycine. 

    Glycine is found abundantly in most high protein food sources such as meat, eggs, legumes, and dairy; however, unlike collagen, these foods contain higher amounts of amino acids considered “essential” and less of the others like proline and hydroxyproline found in collagen. These are important for connective tissue production for healthy joints, skin, hair, and nails, and the scaffolding holds everything in place throughout the body. 

    While pure glycine tastes sweet, larger doses can cause nausea. However, we have great news: you’re already taking the world's highest quality and ethical collagen for your skin, hair, gut, and joint health

    Plus, if you are yet to try incorporating collagen powder into your recipes at home, now's your chance! 

    Pro-tip:Don’t mix your protein supplements since research shows that we can only absorb a limited amount at a time. Take your essential amino acids post-workout to get extra leucine for muscle recovery, and take your collagen at other times, like before bed, so your body has plenty of proline for collagen repair while you sleep. 

    Recipes for Squeezing the Very Zest from Life with Glycine and Collagen:

    Glycine-Infused Herbal Tea: Brew your favorite nighttime herbal tea and add a teaspoon of glycine for sweetness or collagen powder for extra protein for a soothing and restful sleep.

    Protein-Rich Smoothie: Blend a banana, spinach, almond milk, and a scoop of collagen (or two) for a nutritious and energy-boosting smoothie.

    Enhanced Salad Dressing: Make a salad dressing with olive oil, balsamic vinegar, and a dash of glycine for sugar-free sweetness or collagen for a protein boost, and you have a healthy and tasty twist for your salad. 

    Sports + Antiaging Hack: Collagen plus creatine make a powerful combo for sports and anti-aging since creatine boosts ATP, and collagen provides amino acids (including glycine) for tissue healing and repair. You can even take them at night for a deeper, more restful sleep! 

    Quality matters! 

    Many amino acids, including glycine, are made in poorer-quality labs using GMO ingredients, and many are contaminated with heavy metals and other toxins, so be sure to get a high-quality product. 

    Similarly, many collagen powders are made industrially from leftover cow skins. Amandean marine collagen is only sourced from the highest quality wild-caught seafood, so it's clean, green, and uncontaminated. 


    References:

    1. Razak, M. A., Begum, P. S., Viswanath, B., & Rajagopal, S. (2017). Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review. Oxidative medicine and cellular longevity, 2017, 1716701. https://doi.org/10.1155/2017/1716701
    2. Kawai, N., Sakai, N., Okuro, M. et al. The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus.Neuropsychopharmacol 40, 1405–1416 (2015). https://doi.org/10.1038/npp.2014.326
    3. McCarty, Mark F, and James J DiNicolantonio. “The Cardiometabolic Benefits of Glycine: Is Glycine an “Antidote” to Dietary Fructose?” Open Heart, vol. 1, no. 1, May 2014, p. e000103, https://doi.org/10.1136/openhrt-2014-000103. Accessed 14 Nov. 2019.
    4. Mohammed El Hafidi, et al. Glycine Intake Decreases Plasma Free Fatty Acids, Adipose Cell Size, and Blood Pressure in Sucrose-Fed Rats. Vol. 287, no. 6, 1 Dec. 2004, pp. R1387–R1393, https://doi.org/10.1152/ajpregu.00159.2004. Accessed 23 May 2023.
    5. Nagata, Chisato, et al. “Dietary Intakes of Glutamic Acid and Glycine Are Associated with Stroke Mortality in Japanese Adults.” The Journal of Nutrition, vol. 145, no. 4, 28 Jan. 2015, pp. 720–728, https://doi.org/10.3945/jn.114.201293. Accessed 17 Sept. 2022.
    6. Beck, Katherine, et al. “Targeting Glutamate to Treat Schizophrenia: Lessons from Recent Clinical Studies.” Psychopharmacology, vol. 233, no. 13, 23 May 2016, pp. 2425–2428, https://doi.org/10.1007/s00213-016-4318-6. Accessed 9 Sept. 2020.
    7. Ding, Yunpeng, et al. “Plasma Glycine and Risk of Acute Myocardial Infarction in Patients with Suspected Stable Angina Pectoris.” Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, vol. 5, no. 1, 31 Dec. 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4859380/, https://doi.org/10.1161/JAHA.115.002621. Accessed 11 May 2021.
    8. de Paz-Lugo, Patricia, et al. “High Glycine Concentration Increases Collagen Synthesis by Articular Chondrocytes in Vitro: Acute Glycine Deficiency Could Be an Important Cause of Osteoarthritis.” Amino Acids, vol. 50, no. 10, 2018, pp. 1357–1365, www.ncbi.nlm.nih.gov/pmc/articles/PMC6153947/, https://doi.org/10.1007/s00726-018-2611-x.
    9. Hafidi, Mohammed El, et al. “Is Glycine Effective against Elevated Blood Pressure?” Current Opinion in Clinical Nutrition and Metabolic Care, vol. 9, no. 1, Jan. 2006, pp. 26–31, https://doi.org/10.1097/01.mco.0000196143.72985.9a. Accessed 21 Apr. 2020.
    10. Alves, Anaïs, et al. “Glycine Metabolism and Its Alterations in Obesity and Metabolic Diseases.” Nutrients, vol. 11, no. 6, 1 June 2019, p. 1356, www.mdpi.com/2072-6643/11/6/1356/htm, https://doi.org/10.3390/nu11061356.



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