Glycine is an amino acid – a building unit for proteins. It is a nonessential amino acid, meaning that the body can synthesize it, so theoretically it might sound that we do not necessarily need to get glycine from external sources. In practice, however, it is a highly important dietary component. It is found in protein-rich foods such as meat, dairy, eggs, and legumes.
The Many Roles of Glycine
Glycine plays several important roles in our body. It is one of the three amino acids used in the production of glutathione, an antioxidant protecting the cells from damage caused by free radicals. It is also part of creatine, a substance that provides the muscles with ready-to-use energy and also has beneficial effects on the bones and neurological function of the body.
It is also a main component in collagen, a highly important protein that ensures the strength and tone of our skin, muscles, and ligaments.
Several studies have shown that glycine may protect the liver from alcohol-induced damage. It does so by reducing inflammation and stimulating the metabolism of alcohol in the stomach before it reaches the liver. Admittedly, the results of studies done on humans were inconclusive, but nevertheless, it can’t hurt to make sure your diet includes enough glycine.
Glycine may protect against heart disease by helping the body utilize nitric oxide, a molecule that reduces blood pressure and aids blood flow. In addition, it was found that people with a higher level of glycine in their bodies had a better blood cholesterol profile.
Type 2 diabetes is associated with low levels of glycine. In people without diabetes, glycine has been shown to improve responsiveness to insulin, which leads to the conclusion that glycine supplements may be beneficial for people with diabetes. There is not enough research to support definite recommendations on that score, however.
Glycine may also protect against muscle waste in conditions such as cancer, burns, and malnutrition, although once again, more research is needed for decisive conclusions.
Various studies have shown that glycine improves memory and cognitive performance, and may be used in treating neurodegenerative diseases such as Alzheimer’s.
Glycine and Sleep
One of the most interesting effects of glycine is the influence it has on sleep. It turns out that glycine has a soothing effect on the brain and may also lower the core body temperature, which could help you fall asleep and sleep more soundly during the night.
There is a significant correlation between sleep and core body temperature (CBT). CBT drops once you start falling asleep, decreases while you sleep, and rises again once you wake up. Glycine, when taken orally, causes an effect of vasodilation (the dilation of blood vessels), which decreases blood pressure and the core body temperature.
In addition, studies carried out in rats have found that glycine intake results in the release of serotonin, which also contributes to better sleep.
In human trials, it was reported that glycine has significantly reduced the feeling of fatigue in the morning and sleepiness throughout the day – a telltale sign of improved sleep quality.
To sum it up, glycine may help you fall asleep, reduce insomnia, and improve sleep quality, so that you wake up feeling more refreshed in the morning.
Should You Take a Glycine Supplement?
Your body produces endogenous glycine, and most people take approximately 2 grams of glycine in their diet daily. Theoretically, this should be enough for all vital body functions, but various studies have shown beneficial effects of supplementing with larger doses of glycine. So far, there is not enough conclusive data for clinical recommendations, but the good news is, supplementing with glycine is safe in most cases.
Usually, trying a supplement won’t hurt otherwise healthy individuals. Standard supplements offer a dose of 3-5 grams, while much higher doses are generally considered safe.
It has been suggested that glycine supplements may be beneficial in the treatment of schizophrenia, Type 2 diabetes, and minimizing brain damage caused by ischemic stroke.
Combined with a healthy sleep routine, a 3-gram glycine supplement before bedtime may make it easier to fall asleep and improve sleep quality.
Although glycine appears to be safe, it is prudent to use some caution when recommending it to people with kidney or liver disease, patients who have had a stroke, young children, and pregnant or breastfeeding women. Patients who take the antipsychotic drug clozapine should also avoid taking glycine.