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Glycine: The Amino Acid That Keeps On Giving

By Tyler Woodward

If only there was one thing you could take to decrease inflammation, improve digestion, decrease muscle breakdown, balance blood sugar, improve sleep, the list goes on...


What Is Glycine?:

What Is Glycine

Glycine is an amino acid that is found primarily in collagenous tissue, typically found in hair, skin, and joints. Glycine is the lightest amino acid and also has the simplest structure. Glycine is considered a conditionally essential amino acid because your body is capable of producing glycine as long as it has an adequate supply of the essential amino acids. Although the body can produce glycine on its own, it’s not capable of producing enough glycine even in ideal conditions and so some glycine must be consumed through your diet. 

Animal protein is a great source of glycine, except not the parts that most of us are eating today. Muscle meats contain very low amounts of glycine and are much higher in the amino acids tryptophan and methionine. On the other hand animal skin, organs meats, and joints/bones are rich in glycine. As a whole, animal proteins contain a near perfect balance of all the amino acids, as animals are made up of about 50% collagenous protein. But if you only consume muscle meats like many of us do today your diet will be lacking glycine.

What’s So Special About Glycine?

  1. Anti-Inflammatory
  2. Decreases Leaky Gut
  3. Improved Sleep Quality
  4. Protects The Liver
  5. Balances Blood Sugar
  6. Prevents Muscle Breakdown

The List Goes on...

While these profound effects of glycine seem vastly different from one another they are quite interrelated and for the most part, they all start in the gut…

Glycine & The Gut:

Glycine & The Gut

Glycine & Exercise

As you may know our colon is home to trillions of bacteria that can be friendly or not-so friendly to our overall health. The majority of the not-so-friendly are known as endotoxins or lipopolysaccharides (LPS). These bacteria can leak through the wall of your colon and into your bloodstream. When these bacteria leak through your intestines this causes your immune system to react and releases inflammatory cytokines (proteins) in order to “kill” this toxic bacteria. These cytokines bring the “bad bacteria” into the liver where they are broken down and detoxified from the body. Chronic endotoxemia, the consistent presence of high levels of endotoxin in the blood, causes chronic inflammation. This has seen consistently in obese people and may be one of the causes behind the chronic inflammation in obese individuals. 

Although this is not just an issue for overweight or obese individuals. Leaky gut occurs anytime that blood flow to the intestines is restricted for a prolonged period of time. When you exercise your body increases blood flow to the areas that need oxygen, your muscles, and shunts it to the areas that don’t. This results in a decrease in oxygen to many of your organ systems including your intestines. When your intestines don’t get enough oxygen, they can’t produce as much energy. This leaves them ‘open to attack’, so to speak. The living mucus that lines your intestinal wall requires energy to sift through everything that passes through your intestines. When these cells become starved for energy they can’t do their job as well, allowing for more of this “bad bacteria” to pass through into the bloodstream. 

Leaky gut has been shown to occur during intense exercise after only 20 minutes in some cases, but worsens the longer the exercise duration. Long-distance exercise and endurance training is associated with increased levels of gut permeability and inflammation. It’s also believed that the “shaking” of the guts that occurs when you’re moving like running or swimming, literally stirs up the bacteria inside and also increases your gut permeability. 

We’re not saying that exercise is “bad” by any means or not worth performing, but this is one of the reasons why we prefer shorter duration and higher intensity exercise like weight training or sprints.

Glycine & Alcohol

This same effect occurs during the consumption of alcohol. Alcohol also shifts blood flow away to the intestines and to other organs like the muscles, liver, and skin. And, not surprisingly alcohol has been repeatedly associated with increased levels of leaky gut and endotoxin passing through into the bloodstream. Compared to exercise though, alcohol has a doubling down effect. Being that alcohol must also be processed through the liver, the amount of stress or workload on the liver is doubled since it now has to process both the endotoxin released from your intestines and the alcohol itself. On top of this, because the effects of alcohol last for a significantly longer time than exercise, it’s likely that much larger amounts of endotoxin leak through the gut, further burdening your liver and causing more inflammation. 

Glycine has been shown repeatedly to decrease gut permeability by restoring the lining of the intestines. Glycine supplies the body the nutrients it needs to build the collagen and gelatine protein that is found in the gut. It also may act as a direct energy source to the cells in the intestine, helping to supply them with energy even when oxygen is lacking. You can imagine this like fortifying the walls of a castle, so it's more difficult for the” bad bacteria” to pass through. The better sealed the lining of your intestines are, the better of a job it’s able to do in keeping the “bad bacteria” out. 

Glycine & Glutathione

Also, glycine is believed to be the rate-limiting factor in Glutathione production, the body’s master antioxidant. So the amount of glutathione produced is dictated by how much glycine you have available in your body. If you don’t have enough glycine then you cannot produce an optimal amount of glutathione, resulting in increased amount of oxidative stress (inflammation). Guess what happens to be the major antioxidant involved in breaking down alcohol? Glutathione. Without adequate glutathione alcohol will be broken down more slowly, placing additional damage and oxidative stress on the body. This is why glycine is so anti-inflammatory by preventing the damage from occurring in the first place. And for alcohol it not only helps mitigate the damage, but it also helps to detoxify the alcohol faster.

Glycine & Digestion

Last, but not least, glycine is necessary for the production of the bile salts used in digestion. Glycine is combined with the bile acid produced in the kidneys to make bile salts. Bile salts allow you to absorb the fat-soluble vitamins along with other fat-soluble nutrients in the intestines. Without an adequate amount of bile salts, you can’t absorb these essential vitamins and you’ll become deficient in them over time potentially causing a host of metabolic health issues over time.

Read More: What Are Probiotics | Probiotics Explained

Glycine & Blood Sugar:

Blood Sugar & Glycine

When it comes to your cells creating energy, oxygen is only half the equation. Your body needs fuel in combination with oxygen to create a meaningful amount of energy. Your body’s preferred fuel source to create energy is sugar. When your body runs out of sugar it releases the hormones glucagon and adrenaline in order to break down your fat tissue into free fatty acids. These free fatty acids are released into the bloodstream and used as fuel when glucose is unavailable. Short-term this is not a problem, but the issue arises when these free fatty acids get stuck in the bloodstream. When both fat and sugar are in the bloodstream they compete with each other in order to enter into the cell. When there are chronically high levels of fat in the bloodstream, glucose has trouble entering the cell. Insulin normally acts to signal to the cell to absorb glucose to use as energy, but when there is excess fatty acids in the bloodstream it is no longer able to work as efficiently due to the fat competing with glucose to enter the cell. This causes insulin resistance over time which is associated with type II diabetes, obesity, among a host of other diseases.

Luckily, glycine is back at it to save the day. Glycine has been shown repeatedly to increase insulin sensitivity, meaning your body needs to release less insulin in order for your cells to absorb more glucose. It does this by inhibiting lipolysis, the breakdown of fat cells into fatty acids in the bloodstream. This “unclogs” the bloodstream of fatty acids. When there are fewer fatty acids in the bloodstream  insulin can do its job much better by getting more glucose into the cells to be used as energy. 

Read More: Whey Vs. Collagen | Why Collagen Is The Best Protein Supplement

Glycine & The Brain:

Glycine & The Brain

If glycine hasn’t already done enough, it’s also actively involved in the nervous system. Glycine acts as an inhibitory neurotransmitter in the brainstem and spinal cord, meaning it helps to slow down or stop cells from firing. While it’s equally important to be able to produce and use energy it’s equally important to be able to stop and slow down. Your body needs time to recover and without these inhibitory neurotransmitters, it’s like your body is stuck with the gas pedal on the floor. As a neurotransmitter glycine seems to play a number of role in the nervous system

  • Acts As A Vasodilator - Glycine has been shown to have a blood flow boosting effect on the body by opening up the arteries, reducing the core body temperature which has been shown to improve sleep quality.
  • Reduces Insomnia - In a similar manner glycine acts as a neurotransmitter and may also act synergistically with GABA (the brain’s main inhibitory neurotransmitter) to allow you to “shut off” at night and relax, allowing for improved sleep.
  • Neuroprotective - Glycine has been shown to have protective effects on both the brain and the cells by preventing or reducing cytotoxicity. This typically happens when there is an unnaturally large influx of calcium into the cell, throwing off the cell's natural mineral balance, which glycine has been shown to be able to protect the cell from.
  • Reduce Muscle Tone - If you suffer from constantly tight muscles, similarly to your brain they may be stuck in a state in which they cannot turn off. Glycine again acts as an inhibitory neurotransmitter allowing these cells to shut off and relax.
  • Improved Sleep Quality - On top of allowing you to get to sleep faster, glycine may be able to improve the quality of sleep. Glycine’s effect on reducing muscle tone may also play a role in reducing muscle twitches during REM sleep. REM stands for rapid eye movement and can often incur twitching and movements of the other limbs which are normally inactive in sleep. These scientists theorized that a glycine deficiency may play a role in these muscle twitches that occur in REM sleep and supplementing with glycine decreased these twitches and improve sleep quality.

Glycine & The Body:

Glycine & The Body

Last, but not least, how could we forget about glycine’s most famous role as one of the key players in making collagen. Collagen is the most abundant protein in the body and is found just about everywhere, but predominantly in the hair, skin, nails, and your joints. So it shouldn’t come as a surprise that glycine has a ton of benefits in the body as well:

Best Sources Of Glycine:

  • The Skin Of Pigs & Chicken - Make sure to try and get pasture-raised pork and chicken, as skin tends to be rather fatty and because pigs and chicken are monogastric animals (one stomach) their skin tends to be fill with the toxic polyunsaturated fats from the corn and soy they are fed. 
  • Shellfish
  • Organ Meats
  • Bone/Joints
  • Collagen Protein or Bone Broth

How Much Glycine Should You Be Consuming?

PhD Chris Masterjohn estimates that for every gram of methionine you consume you should consume between .5-1 gram of glycine. Methionine is one of the main amino acids in muscle meats and actually depletes your body of its glycine stores. So basically, the more methionine you consume, the higher your glycine requirements are. Masterjohn recommends as a rule of thumb to try and consume about 10% of your daily protein intake from a collagenous source of protein or protein supplement. So if you consume 100 grams of protein daily, you should try to consume 10 extra grams of collagen. 

Ray Peat on the other hand believes that after you stop growing, basically the more collagen the merrier, as we no longer need to consume much of the amino acids found in muscle meats as we age. At the minimum Ray recommends trying to balance your amino acid intake by adding in some collagen or gelatin when you consume muscle meats. 

I’d argue that Glycine’s not a supplement, but a dietary “essential”. About 50% of the protein in animals is collagenous tissue which are a rich source of the amino acids glycine, proline and hydroxyproline. I think it’s pretty safe to say that our ancestors likely didn’t waste any part of an animal, nonetheless 50% of the protein. While it’s become a societal norm to only eat muscle meats, you’re completely denying your body of the amino acid balance that results from eating the entire animal. Bones, joints, skin are things that we often skimp out on today, but are rich in these amino acids. And luckily for you, if you don’t want to make your own bone broth or collagen, we have just the right thing for ya...

Zucollagen & broth

zuCollagen & zuBroth are UMZU's premier collagen supplements sourced from Organic, Grass-Fed cows and contain over 5 grams of glycine per serving! We believe these are truly the highest quality and best tasting protein powders on the market! Try zuCollagen & zuBroth out risk-free today and you won't be disapointed!


My goal in writing this article, as always, is to provide you with logically-based principles that you can use to form your own conclusions regarding any information you may come across within this subject. I really hope you found this article interesting and if you have anything to add to this article, or any comments or criticism, feel free to reach out to me on our facebook groups or on Instagram @tylerwoodward_fit. Also, please feel free to share this article with anyone that might be interested.

Thanks for reading!

Until next time… be good

~Tyler Woodward