What is glycine used for? Benefits and properties

Recognizing glycine as one of the most indispensable nonessential amino acids for athletes is the first step toward understanding it, right?.

The amino acid glycine is not considered an essential amino acid because the body can synthesize it. It does so by going to the biochemical kitchen and producing it from other chemicals, mainly serine, but also choline with a touch of threonine.

Regardless, the typical person consumes around 2 g of glycine per day, mainly through meat, fish, dairy products, and other protein-rich foods.

However, its «nonessential» label, although chemically correct, diminishes its perceived value. Biochemists and nutritionists dismiss it because they do not take into account some of its recently discovered talents as a nutraceutical.

Specifically, supplementing the diet with glycine can dramatically improve collagen synthesis, potentially leaving other supposed collagen restorers such as glucosamine and chondroitin in the dust.

What is glycine?

Glycine is one of the many amino acids used to produce proteins. It is the smallest of all amino acids and is surprisingly important for the synthesis of other amino acids such as glutathione, creatine, heme, RNA/DNA, as well as potentially helping with calcium absorption in the body.

It is essential for maintaining the structure of tissues, joints, and blood vessels. It also promotes healthy skin, hair, and nails.

Although technically called a «nonessential amino acid», the amounts we synthesize plus the dietary amounts we consume may not reach the quantity needed for optimal metabolic function.

Although its deficiency is not life-threatening, studies show that low levels can compromise the synthesis of important enzymes and proteins that could have detrimental effects on health.

What is the history of glycine?

Researchers have studied glycine and its effects on the body for decades. The French chemist H. Braconnot discovered this nonessential amino acid in 1820 by isolating it from the acid hydrolysates of proteins: superior-quality protein.

This amino acid tastes sweet like glucose, so its name derives from the Greek word «glyks» because of its sweet characteristic.

• It is found in the central nervous system and stored in the spinal cord, brainstem, and retina (the back layer of the eyeball).
• It functions as a neurotransmitter and acts as a catalyst in many of the body's daily functions related to the nerves and muscles of the central nervous system.

Medically, it is considered the simplest amino acid, with hydrogen as its side chain.

For any athlete, most foods that contain high levels of the amino acid are also rich in protein. Fish, eggs, legumes, dairy products, red meat, poultry, nuts, and processed meats, as well as seaweed, watercress, and spinach—foods that are present in a sports diet—are necessary and consistent sources for the body to function properly.

Nevertheless, after many years of experimentation, the industry has become interested in developing sports nutrition products with glycine with greater bioavailability, specifically for health, bodybuilding, and fitness.

How does glycine interact with bodybuilding?

Without glycine, the body cannot create creatine. Bodybuilders use creatine supplementation to gain strength and muscle mass.

• A high dose can cause a rapid increase in the release of growth hormone from the pituitary gland, by up to 60% in less than 5 minutes.
• A quick boost in growth hormone after training can help stimulate protein synthesis, build muscle, and promote faster recovery.

Glycine helps inhibit muscle breakdown, in addition to enhancing muscle recovery. Furthermore, since it provides energy to cells by increasing ATP production to support muscle tissue, it also increases endurance, strength, and performance.

On the other hand, it has a beneficial effect on hormone production and regulation, contributing to the natural synthesis of steroid hormones that control how energy is allocated for use and regulate the ratio of fat to muscle mass.

In summary, by taking glycine in its free amino acid form, you have a great option for achieving your athletic or aesthetic goals.

What are the other benefits of glycine

Although some have studied it extensively for certain purposes, its circumstances allow it to cover a wide range of situations.

From this perspective, specifically in sports, the benefits of glycine are clear and compelling in their effectiveness:

• It synthesizes collagen, making a major contribution to cartilage formation, which is relevant for sports.
• It generates energy while also recycling old cells, which may help you live longer—in other words, it may promote longevity.
• By improving brain signaling, it helps the mind function better in coordination with the muscles.
• It improves insulin sensitivity, reducing abdominal fat and maintaining metabolic health.
• It may act as a liver protectant by helping synthesize glutathione.
• It acts as a powerful anti-inflammatory, reducing oxidative stress.
• It promotes better anabolic sleep by reducing body temperature as the day comes to an end.

Glycine is used to synthesize collagen.

Cartilage regeneration requires large amounts of the amino acids proline, lysine, and glycine. A group of Spanish scientists wanted to assess the comparative contributions of each to the production of the cartilage molecule [1].

To address this, they cultured bovine chondrocytes using a wide range of concentrations of these amino acids.

Both proline and lysine improved collagen synthesis, but the effects declined before reaching 1.0 mM (a measure of the concentration of a chemical substance in solution).

In contrast, glycine also improved collagen synthesis, but the effects did not decline before reaching a concentration of 1.0 mM. In fact, the increase in synthesis continued by 60–75%.

The researchers concluded the following:

• One of the benefits of glycine in the diet is helping cartilage regeneration by improving collagen synthesis.
• This could contribute to the treatment and prevention of osteoarthritis and may even be a nutritional element that is key for high-performance athletes.

Glycine generates energy and may promote longevity.

Mitochondria are tiny cellular “organelles” that, as the word suggests, are like miniature organs.

Like organs, each one has specific functions; in this case, producing energy in the form of ATP, the cell’s energy currency. They do this by metabolizing sugars, fats, and other chemical substances with the help of oxygen.

Metabolically active cells such as those in the liver, kidneys, heart, brain, and muscles have so many mitochondria that they can make up 40% of the cell, while other less active cells such as blood and skin cells have very few.

In addition to producing all the energy our bodies need, they also play a fundamental role in the aging process.

There are several theories about how they do this, but a group of Japanese researchers believes that it is largely because old mitochondria simply do not function as hard as younger mitochondria.

Japanese research had established that the GCAT gene was involved in glycine production, and when they deactivated the GCAT gene in young fibroblasts, their energy expenditure decreased. Conversely, when they activated that same GCAT gene, energy expenditure increased again [2].

They decided to experiment further, but this time they exposed old fibroblasts directly to glycine, and energy levels increased significantly.

Their results suggest that:

• Simply adding more glycine to the diet could make old cells act young again and possibly delay aging.
• Likewise, as a “side effect,” the body may become significantly energized, which also contributes to overall well-being over the years.

Glycine, an additional boost for focus

The effects of this amino acid, although little studied, are of interest to those who want to improve cognitive performance.

The amino acid plays an important role in neurotransmission in the central nervous system, which means brain signaling, so increasing its levels may actually lead to lower levels of negative mental states, in addition to possibly benefiting memory.

Overall, by providing better cognition, memory, and brain signaling, glycine plays a central role in focus, an element of great importance in the mind-muscle connection.

Glycine reduces insulin resistance

This amino acid may also benefit our metabolic health and help people with diabetes.

Higher serum glycine levels are associated with less insulin resistance, better insulin sensitivity, and less abdominal fat, a risk factor linked to metabolic disorders.

Free fatty acids in the blood are not good. Here, it can help by lowering glycated hemoglobin, which leads to poor glucose control in people with type 2 diabetes. In addition, glycine stimulates glucagon, which helps insulin remove glucose from the body.

Better glucose regulation has profound health benefits for everyone, not just people with diabetes. The ability to better regulate blood sugar levels throughout the day can benefit mental and physical performance. Avoid the sugar crash!

Glycine acts as a liver protector

The liver is the body's built-in detoxification system. Its function is to remove toxins from the body by breaking them down, conjugating them into bile, or sending them to the kidneys for excretion.

• The body's strongest and most versatile detoxifying substance is glutathione, and we cannot produce glutathione without glycine.
• Most glutathione biosynthesis occurs in the liver, but the body's reserves are easily depleted.

Benzoates, which are additives in foods and soft drinks, can bind to glycine, depleting our body's valuable glycine reserves.

The amino acid may be particularly useful for those who consume a lot of alcohol or processed food because it reduces the buildup of LDL cholesterol, free fatty acids, and triglycerides in the blood, liver, and brain. It may also delay damage caused by liver injuries or diseases.

Glycine reduces inflammation and oxidative stress

Glycine plays a vital role in the formation of glutathione, which in turn helps maintain redox balance in the body to reduce the risk of damage from excessive oxidative stress and the associated inflammation.

Reducing inflammation and oxidative stress has numerous benefits, from disease prevention to improved mental health and physical performance.

Glycine helps you sleep better

We all need sleep. It is our basic human need; if you train hard, you depend on that period to build muscle through your hormones.

Unfortunately, many of us experience sleep problems. Needless to say, sleep problems have become a widespread health issue, and research shows that lack of sleep affects everything from mental capacity to an increased risk of chronic diseases and reduced physical performance.

Here, glycine, which induces vasodilation throughout the body, promotes a decrease in core body temperature, helping you sleep better.

• Sleep and body temperature are intertwined: body temperature decreases before sleep begins and continues to decrease throughout the night, reaching its lowest point approximately 2 hours after sleep onset and gradually increasing as the person wakes up.
• Temperature is just one of the many 24-hour rhythms our bodies experience throughout the day and, as night approaches, the decrease is important for initiating sleep.

What types of glycine supplements exist?

Glycine supplements are the foundation of protein synthesis, as well as being key to repairing and protecting muscles, among other cited benefits.

In general, they are manufactured with high purity, have good or excellent solubility, and brands promote them as suitable for vegans or vegetarians.

It is sold as an isolated powder, as a mineral bisglycinate, or as GPLC (glycine propionyl L-carnitine), among other forms.

What is the best daily dose of glycine?

Humans normally consume around 2 to 3 grams of amino acids from food, and the body generally produces another 3 grams on its own. Experts suggest that we could benefit from much more, up to around 10 additional grams or so.

However, bodybuilders generally have an advantage in their intake over the average person because they normally consume a large amount of protein, which strengthens their glycine reserves.

Even so, it may be sensible to consume an additional 3, 4, or 5 grams of glycine per day, either through a daily collagen supplement (collagen is rich in glycine) or an isolated product.

How should glycine supplements be taken?

On the one hand, taking glycine with creatine or carbohydrates is recommended because it improves protein and carbohydrate absorption. At the same time, it is an amino acid that helps burn fat.

It can be taken during or after training to help you naturally get the most out of a demanding workout. As an amino acid, it also supports the bones, intestines, and various metabolic markers.

Likewise, taking between 6 g and 8 g of glycine 30 minutes before bedtime can greatly improve your sleep quality.

Conclusions

Glycine is a nonessential amino acid that helps promote essential immune functions in the body. It supports the body's ability to develop collagen, found in bones, cartilage, ligaments, skin, and muscles. The medical field considers glycine a vital nonessential amino acid found in humans, animals, and mammals.

The amino acid functions as a natural neurotransmitter and also acts as an anti-inflammatory, antioxidant, and immune system modulator in peripheral and nervous tissues. This function aims to help the body combat inflammation and break down potentially harmful substances in the body.

In its natural form in the body, it restores glutathione and helps protect against oxidative stress, which may help relieve stress-related disorders.

Glycine promotes well-being In general, enhancing athletic performance and producing better training results.

For athletes who benefit from its contribution to health and well-being, its high protein content can also help protect muscles, promote liver health, and act as a sleep aid, resulting in stimulation of anabolic hormones.

Although you can consume glycine through food, an intense training routine requires taking a supplement, provided that you follow the instructions of your trainer or nutritionist, or even your doctor.

If you need a multifaceted supplement to give you strength, prevent muscle deterioration, help you relax from stress, sleep well, or combat inflammation (or related pain), glycine may be the ideal supplement to add to your sports nutrition stack.

Finally, we would like to share a video discussing the differences between proteins and amino acids.

References

• [1] Amino Acids. 2018: High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis.
• [2] Sci Rep. 2015: Epigenetic regulation of the nuclear-coded GCAT and SHMT2 genes confers human age-associated mitochondrial respiration defects