4 Sleep Benefits of Glycine
This amino acid enhances sleep and supports whole-body health.
Posted February 13, 2019 | Reviewed by Jessica Schrader
You might not know it by name, but the tiny amino acid glycine is hard at work in your body right now, maintaining strength and support in your muscles and bones, helping keep your metabolism functioning right, supporting a healthy brain, and contributing to a good night’s sleep.
For all its power to support the body’s health and natural capacity for healing, glycine has gotten strangely little attention as a natural remedy. Let’s take a look at some of what we know today about glycine—how it works in the body, and what additional glycine might do to affect your health and sleep.
What is glycine?
Glycine (also known as 2-Aminoacetic Acid) is an amino acid and a neurotransmitter. The body produces glycine on its own, synthesized from other natural biochemicals, most often serine, but also choline and threonine. We also consume glycine through food. This amino acid is found in high-protein foods including meat, fish, eggs, dairy and legumes. A daily diet typically includes about 2 grams of glycine.
Glycine is a neurotransmitter with the ability to be both excitatory and inhibitory, meaning it can function both to stimulate brain and nervous system activity, or to quiet it.
People use glycine as an oral supplement for a range of purposes, including improving sleep, enhancing memory, and increasing insulin sensitivity. Glycine is also available in topical form, and used to heal wounds and treat skin ulcers.
Glycine has a sweet taste, and is manufactured commercially as a sweetener and included in products such as cosmetics and antacids. Its name comes from the Greek word, glykys, which means “sweet.”
Glycine is sometimes used in the treatment of schizophrenia, typically alongside conventional medication, to help reduce symptoms. Glycine is also given orally to patients who’ve suffered ischemic stroke (the most common type of stroke), as a treatment to help limit damage to the brain within the first six hours of the stroke.
How does Glycine work?
Glycine is considered among the most important amino acids for the body. It exerts widespread influence over our bodies’ systems, structure, and general health, including cardiovascular, cognitive, and metabolic health. Here are some of the most important and well-understood roles that glycine plays in our health and functioning:
As an amino acid, glycine works as a protein builder in the body. In particular, glycine enables the production of collagen, a protein that is an essential component of muscles, tendon, skin, and bones. Collagen is the most commonly occurring protein in the body, comprising roughly a third of all body protein. It does no less than give the body its fundamental structure and strength. Collagen is the protein that helps skin maintain elasticity. Glycine also facilitates the production of creatine, a nutrient stored in and used by both the muscles and the brain for energy.
Glycine is involved in digestion, specifically in the breakdown of fatty acids in foods. It also helps maintain healthy levels of acidity in the digestive tract.
Glycine is also involved in the body’s production of DNA and RNA, the genetic instructions that deliver our body’s cells the information they need to function.
This amino acid helps to regulate blood sugar levels and move blood sugar to cells and tissues throughout the body, to be consumed as energy.
Glycine helps to regulate the body’s immune response, to limit unhealthful inflammation and spur healing.
As a neurotransmitter, glycine both stimulates and inhibits cells in the brain and central nervous system, affecting cognition, mood, appetite and digestion, immune function, pain perception, and sleep. Glycine is also involved in the production of other biochemicals that influence these body functions. In particular, glycine helps the body make serotonin, a hormone and neurotransmitter that has significant effects on sleep and mood. It also influences key receptors in the brain that affect learning and memory.
Benefits of Glycine
For sleep: Glycine influences sleep in a number of ways. Studies show that higher levels of this amino acid may:
- Help you fall asleep more quickly.
- Increase your sleep efficiency.
- Reduce symptoms of insomnia.
- Improve sleep quality and promote deeper more restful sleep.
How does glycine accomplish all of this sleep-promoting work? It appears to affect sleep in at least a couple of important ways:
Glycine helps lower body temperature. Glycine works to increase blood flow to the body’s extremities, which reduces core body temperature. I’ve written before about how the body’s fluctuating temperature affects sleep-wake cycles, and your ability to initially fall asleep. A slight drop in body temp is a key part of the body’s physical progression into sleep. A recent study of the effects of glycine as a supplement showed it triggered a drop in body temperature and at the same time helped people both fall asleep more quickly and spend more time in REM sleep. Other research has shown supplemental glycine may help you move more quickly into deep, slow wave sleep.
Glycine increases serotonin levels. Serotonin has a complex relationship to sleep. Among other things, serotonin is required to make the sleep hormone melatonin. In people who have difficulty sleeping or sleep disorders such as insomnia and sleep apnea, increasing serotonin levels can help restore healthy sleep patterns, and encourage deeper, more restful and refreshing sleep. Research shows oral glycine elevates serotonin, reduces symptoms of insomnia, and improves sleep quality. Other studies suggest it may help you bounce back to healthy sleep cycles after a period of disrupted sleep.
- For cognitive and memory enhancement: Glycine is active in the hippocampus, an area of the brain important for memory and learning. In supplement form, glycine appears to deliver benefits for daytime cognitive function. In the same study that showed supplemental glycine made it easier to fall asleep and get to slow-wave sleep, scientists also found people scored higher on daytime cognition tests. And supplemental glycine has been shown to improve both memory and attention in young adults. Scientists are actively investigating the use of glycine in the treatment of neurodegenerative disorders such as Alzheimer’s disease.
- For cardiovascular health: Glycine works to support immune health and keep inflammation in check, offering protection to cardiovascular function. It also functions as an antioxidant, helping to trap and contain damaged cells that can cause disease. Higher levels of glycine have been associated with a lower risk of heart attack, and there’s some evidence that glycine may help protect against high blood pressure. Still, the full relationship between glycine and cardiovascular health is something scientists are still working to better understand.
- For joint and bone health: Glycine is one of the most important, protein-fueling amino acids in the body. It supplies our muscles, bones, and connective tissues with collagen, the protein that is essential to your strength, stability, and healthy physical function. As we age, collagen levels in the body naturally decrease. Glycine is also very effective at suppressing inflammation. Supplemental doses of glycine may help strengthen bones and joints, and may help prevent arthritis.
- For metabolic health: Glycine plays an important role in a healthy metabolism. Low levels of glycine are linked to greater risk for development of type 2 diabetes. On the other hand, higher glycine levels are associated with lower risk for this metabolic disorder. But it’s not yet clear what the cause and effect are in this relationship: whether low glycine levels directly contribute to metabolic dysfunction that lead to diabetes, or whether they’re a result of metabolic dysfunction already in progress. Studies show glycine can be effective in lowering blood sugar levels and increasing insulin production in healthy adults. In people with type 2 diabetes, studies have shown that glycine deficiencies can be improved by use of oral glycine. Other research suggests that in people with diabetes, oral glycine can lower blood sugar levels.
What to know
Always consult your doctor before you begin taking a supplement or make any changes to your existing medication and supplement routine. This is not medical advice, but it is information you can use as a conversation-starter with your physician at your next appointment.
- For sleep: A range of 3-5 grams of glycine taken orally before bed has been used effectively to help sleep in scientific studies.
- For blood sugar: A range of 3-5 grams of glycine taken orally at meals has been used effectively to reduce blood sugar in scientific studies.
Possible side effects
Glycine is generally well tolerated by healthy adults. Side effects are uncommon, but may include:
- Mild stomach upset
- Soft stools
- Glycine interactions
There are commonly used medications and supplements that have scientifically-identified interactions with glycine. People who take these or any other medications and supplements should consult with a physician before beginning to use glycine as a supplement.
Women who are pregnant or breastfeeding: It’s recommended to avoid glycine use during pregnancy and breastfeeding, primarily because there currently isn’t sufficient evidence about the safety of use during these conditions.
Interactions with medications
Clozapine. This drug (brand name Clozaril) is used in the treatment of schizophrenia. Using glycine in combination with clozapine may reduce the effectiveness of clozapine. It’s recommended people who are taking clozapine not use glycine.
Interactions with other supplements
There are currently no known interactions with herbs and supplements.
When you talk to your physician about taking glycine, be sure to include information about the supplements you’re already taking.
Glycine is a pretty fascinating natural biochemical, with benefits that stretch from physiological health, strength, and vitality, to more robust mental performance, to better sleep. Because of its wide-ranging impact, I expect we’ll see increasing attention to how supplemental glycine can help us protect our health and our sleep.
Michael J. Breus, Ph.D., DABSM