Glycine is an amino acid that your body uses to create proteins, which it needs for the growth and maintenance of tissue and for making important substances, such as hormones and enzymes.
Your body naturally produces glycine from other amino acids, but it’s also found in protein-rich foods and available as a dietary supplement.
Along with being a component of protein, glycine has several other impressive health benefits.
Here are the top 9 health benefits and uses of glycine.
Glycine is one of three amino acids that your body uses to make glutathione, a powerful antioxidant that helps protect your cells against oxidative damage caused by free radicals, which are thought to underlie many diseases (1).
In addition, because glutathione levels naturally decline with age, ensuring that you get enough glycine as you get older may benefit your health.
Summary Glycine helps your body make glutathione, an important antioxidant that protects your body against cell damage.
Glycine is also one of three amino acids that your body uses to make a compound called creatine.
Creatine provides your muscles with energy to perform quick, short bursts of activity, such as weightlifting and sprinting.
While your body naturally creates creatine and it can be obtained through your diet, getting too little glycine may reduce how much you produce (10).
Summary Glycine is a component of creatine, a compound that provides your muscles with energy and has been associated with other health benefits, such as improved bone health and brain function.
Collagen is a structural protein that contains high amounts of glycine. In fact, every third to fourth amino acid in collagen is glycine (11).
Collagen is the most abundant protein in your body. It provides strength for your muscles, skin, cartilage, blood, bones and ligaments.
Therefore, it’s important that you get enough glycine to support your body’s production of collagen.
Summary Glycine is the most abundant amino acid in collagen, a structural protein that has several health benefits, including for your skin, joints and bones.
Many people struggle to get a good night’s rest, either because they have trouble falling or staying asleep.
While there are several ways you can improve your sleep quality, such as not drinking caffeinated beverages late in the day or avoiding bright screens a few hours before bedtime, glycine may also help.
Research in people with sleep issues has shown that taking 3 grams of glycine before bed decreases how long it takes to fall asleep, enhances sleep quality, lessens daytime sleepiness and improves cognition (17, 18).
For this reason, glycine may be a good alternative to prescription sleeping pills for improving sleep quality at night and tiredness during the day.
Summary Glycine may promote sleep and enhance the quality of your sleep through its calming effects on the brain and its ability to lower core body temperature.
Too much alcohol can have damaging effects on your body, especially your liver.
There are three primary types of alcohol-induced liver damage (19):
- Fatty liver: A buildup of fat inside your liver, increasing its size.
- Alcoholic hepatitis: Caused by inflammation of the liver resulting from long-term, excessive drinking.
- Alcoholic cirrhosis: The final phase of alcoholic liver disease, occurring when the liver cells are damaged and replaced by scar tissue.
Interestingly, research suggests that glycine may reduce the harmful effects of alcohol on your liver by preventing inflammation.
It has been shown to reduce concentrations of alcohol in the blood of alcohol-fed rats by stimulating the metabolism of alcohol in the stomach rather than the liver, which prevented the development of fatty liver and alcoholic cirrhosis (20).
What’s more, glycine may also help reverse liver damage caused by excessive alcohol intake in animals.
While moderate alcohol-induced liver damage can be reversed by abstaining from alcohol, glycine may improve the recovery process.
In a study in rats with alcohol-induced liver damage, the liver cell health returned to baseline 30% faster in a group fed a glycine-containing diet for two weeks compared to a control group (21).
Summary Eating a diet with glycine decreases and reverses alcohol-induced liver injury in rats, but its effects in humans are unknown.
Increasing evidence suggests that glycine offers protection against heart disease.
In an observational study in over 4,100 people with chest pains, higher levels of glycine were associated with a lower risk of heart disease and heart attacks at a 7.4-year follow-up (28).
What’s more, glycine has been found to reduce several risk factors of heart disease in rats fed a high-sugar diet (29).
Eating and drinking too much added sugar can raise blood pressure, increase levels of fat in your blood and promote dangerous fat gain around the belly — all of which can promote heart disease (30).
While encouraging, clinical studies on the effects of glycine on heart disease risk in humans are needed before it can be recommended (31).
Summary Glycine may lower heart disease risk factors by preventing the build-up of a molecule associated with heart disease and by increasing your body’s ability to use nitric oxide.
Type 2 diabetes may lead to low levels of glycine.
It’s a condition characterized by impaired insulin secretion and action, meaning your body doesn’t produce enough insulin or that it doesn’t respond properly to the insulin it makes (32).
Insulin decreases your blood sugar levels by signaling its uptake into cells for energy or storage.
Interestingly, because glycine has been shown to increase insulin response in people without diabetes, it's suggested that glycine supplements may improve impaired insulin response in people with type 2 diabetes (11, 33, 34).
Therefore, people with type 2 diabetes may benefit from supplementing with glycine, though research is too preliminary to make any specific recommendations.
Summary Supplementing with glycine may improve impaired insulin action, a hallmark of type 2 diabetes. However, research to make any specific recommendations for its use in people with the condition is insufficient.
Glycine may reduce muscle wasting, a condition that occurs with aging, malnutrition and when your body is under stress, such as with cancer or severe burns.
Muscle wasting leads to a harmful reduction in muscle mass and strength, which declines functional status and can complicate other potentially present diseases (38).
The amino acid leucine has been studied as a treatment for muscle wasting, as it strongly inhibits muscle breakdown and enhances muscle building (39).
However, several changes in the body during muscle-wasting conditions impair the effectiveness of leucine for stimulating muscle growth.
Therefore, glycine holds promise for improving health by protecting muscles from wasting during various wasting conditions (42).
Still, more research in humans is needed.
Summary Glycine may preserve muscle mass in wasting conditions, such as cancer, malnutrition and burns, though more research in humans is needed.
Glycine is found in varying amounts in meat, especially in tough cuts like the chuck, round and brisket.
You can also get glycine from gelatin, a substance made from collagen that’s added to various food products to improve consistency.
Other and more practical ways to increase your intake of glycine include:
Add It to Foods and Drinks
Glycine is readily available as a dietary supplement in capsule or powder form. If you don’t like taking pills, the powder form dissolves easily in water and has a sweet taste.
In fact, the name glycine is derived from the Greek word for “sweet.”
Due to its sweet taste, you can easily incorporate glycine powder into your diet by adding it to:
- Coffee and tea
- Protein shakes
Take Collagen Supplements
Glycine is the main amino acid in collagen, the main structural protein of connective tissue, such as bone, skin, ligaments, tendons and cartilage.
Accordingly, you can boost your glycine intake by taking collagen protein supplements.
This is likely more efficient, as glycine competes with other amino acids for absorption and is therefore absorbed less efficiently by itself than when it's bound to other amino acids, as in the case of collagen (43, 44).
Is Glycine Safe?
Supplementing with glycine is safe in appropriate amounts.
Studies have used up to 90 grams of glycine per day over several weeks without serious side effects (45).
For comparison, the standard dose used in studies is about 3–5 grams per day.
Summary Glycine powder is readily available and can easily be added to your favorite drinks and some foods. Collagen supplements are also an efficient way to boost your glycine intake. Both methods are a safe way to get more of this important nutrient.
Glycine is an amino acid with many impressive health benefits.
Your body needs glycine to make important compounds, such as glutathione, creatine and collagen.
This amino acid may also protect your liver from alcohol-induced damage and improve sleep quality and heart health.
What’s more, glycine may also benefit people with type 2 diabetes and protect against muscle loss that occurs with muscle-wasting conditions.
You can increase your intake of this important nutrient by eating some meat products, by adding the powdered supplement form to drinks and foods or by supplementing with collagen.