Glycine is an amino acid that the body naturally produces and uses to create protein. You can also get glycine by eating protein-rich foods or taking it as a dietary supplement.
Glycine plays a key role in multiple functions of the body, acting as an antioxidant, anti-inflammatory compound, immune system modulator, and more. Research suggests it may have numerous health benefits, including supporting treatment for certain health conditions and enhancing sleep quality.
Supplementing with glycine may help improve the quality of sleep—particularly in people who experience sleep issues or sleep disorders like insomnia.
Glycine may help promote healthy sleep because it helps lower your core body temperature, which signals the body to fall and stay asleep. For example, one study found taking 3 grams (g) of glycine before bedtime improved sleep quality in people with sleep complaints. The participants also reported feeling less tired and fatigued the next day than usual.
Other research showed that taking glycine in combination with other supplements—like magnesium, tryptophan, and L-theanine—increased total sleep time and reduced morning sleepiness.
Protects Heart Health
The anti-inflammatory and antioxidant properties of glycine make the amino acid helpful for preventing cell damage and inflammation—which can help reduce heart disease risk.
Evidence suggests glycine may help prevent the arteries from hardening and narrowing. Other research has found glycine may also support how the body uses nitric oxide, a compound that helps increase blood flow and lower blood pressure.
One study investigated a potential link between glycine levels and heart attack. It found that people with higher glycine levels in blood plasma (the liquid portion of blood) had a lower risk for heart attack and a better blood cholesterol risk profile.
While these results are promising, additional scientific evidence is needed before glycine can be broadly recommended as a heart health supplement.
People with type 2 diabetes can't produce enough or respond effectively to insulin, a hormone in the body that’s meant to regulate blood sugar levels.
Initial research shows that glycine can help improve insulin sensitivity—how the body responds to insulin. Glycine may also help facilitate the body's use of glucose (glucose) for fuel rather than storing it as fat cells, ultimately helping reduce blood sugar levels in people with type 2 diabetes.
However, there is not yet enough research for experts to officially recommend glycine supplementation for people with type 2 diabetes. It’s best to follow your healthcare provider’s treatment plan to manage insulin resistance.
Potentially Supports Schizophrenia Treatment
Some studies suggest glycine supplementation can support treatment for schizophrenia—a brain disorder that can cause symptoms like hallucinations and social withdrawal.
Some research has shown that taking glycine with certain antipsychotic medications can improve symptoms of schizophrenia, including social withdrawal and apathy. However, the research found that glycine doesn't appear to improve positive schizophrenia symptoms, like hallucinations and delusions.
If you have schizophrenia or another health condition, always check with a healthcare provider before stopping, adjusting, or adding to your medication protocol.
Supplementing with glycine may help support cognitive function and short-term memory in some people.
Older research suggests taking glycine helped certain aspects of memory in people who were experiencing age-related memory decline. A few smaller studies in adults at risk for developing a mental health disorder reported improved cognitive performance and memory in participants who took a small dose of glycine once or twice daily for 24 weeks.
Much more research is needed to confirm and expand upon these findings.
How To Take Glycine
Glycine is available as a supplement and can be taken orally in the form of a capsule or dissolvable powder. Some people may find that taking supplements like glycine with a meal or before bedtime is ideal to avoid stomach-related side effects.
Depending on the supplement and dosage instructions, you may take glycine once per day or in two separate daily doses.
Dosage
There is not a standard recommended dose for glycine supplementation. You should follow the dosing instructions provided by the product manufacturer, unless your healthcare provider has prescribed you a specific dose.
However, glycine is most commonly taken in doses of up to 3 g daily for up to 24 weeks. Some studies have found that taking up to 6 g of glycine daily for 4 weeks is safe.
When taken by mouth, glycine appears to be safe for most healthy adults. However, there isn't extensive research on long-term supplementation of glycine, so you should still talk to a healthcare provider before adding this to your routine.
There isn't enough information or evidence about the safety of taking glycine while pregnant or breastfeeding, so experts recommend avoiding this supplement during those times.
Potential Drug Interactions
Glycine supplements may interact with the antipsychotic drug Clozaril (clozapine), decreasing its effectiveness. A smaller study on people with schizophrenia showed that taking glycine with Clozaril made the disorder's symptoms worse compared to just using the prescription medication alone.
If you are taking any medications, talk to your healthcare provider before taking a glycine supplement to ensure it is safe for you.
What To Look For
Foods that naturally contain glycine include protein sources like meat, poultry, fish, dairy products, beans, and legumes. You can also find glycine as an oral supplement—look for reputably sourced supplements with a label that reads 100% pure glycine. Taking collagen supplements can also increase your glycine intake.
The U.S. Food and Drug Administration (FDA) doesn't regulate supplements like it does medications, so it's important to choose a product that has been third-party tested for quality and safety.This indicates that the product's label ingredients are accurate. Reputable third-party testing organizations include U.S. Pharmacopeia and ConsumerLab.
Can You Take Too Much Glycine?
There hasn't been enough research to suggest an upper limit for glycine. Some studies have shown doses of up to 9 g daily for 3 days to be safe.
When taking a glycine supplement, also factor in your glycine intake from food. A typical adult diet contains around 2 g of glycine daily through high-protein foods like meat, dairy, and legumes.
Side Effects of Glycine
Glycine is generally considered to be well-tolerated without any major adverse effects. Some people may experience some minor side effects, such as:
- Stomach discomfort
- Soft stools
- Nausea
- Vomiting
- Mild sedation
Glycine is an amino acid that your body naturally produces and uses for multiple bodily functions. Studies point to numerous glycine health benefits, including sleep improvement, type 2 diabetes treatment support, heart health protection, cognitive function enhancement, and more.
You get some glycine through your diet from meat, fish, dairy, and legumes. You can also take it as a supplement. While glycine supplementation is considered to be safe for most healthy adults, it's best to talk to a healthcare provider before adding a new supplement to your daily routine.
