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Glycine: The Amino Acid That Keeps On Giving

By Tyler Woodward

Glycine truly is the amino acid that keeps on giving. Glycine has been shown to have an abundance of benefits to include fighting inflammation, healing the gut, improving sleep, and more.


What Is Glycine?:

What Is Glycine


What Is Glycine?:

Glycine is the lightest and simplest amino acid that is found primarily in collagenous tissue like hair, skin, and joints. 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 other essential amino acids needed to make it. Even though the body should be able to produce the glycine it needs, it is still beneficial to supplement with some added 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 benefits of glycine span the body and are interrelated.  A strong commonality of these benefits is that they all start in the gut…

You may be wondering, where you can get glycine supplementation into your diet. 

Animal protein is a great source of glycine. The catch is, most people don’t typically consume the glycine-rich aspects of the animal. Muscle meats contain very low amounts of glycine and are much higher in the amino acids tryptophan and methionine. On the other hand, collagenous tissues like 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, as many people do, your diet will be largely lacking in glycine.


Looking for a convenient way to get  all of the benefits of glycine in one convenient scoop? Made from grass-fed beef and 5 types of high-quality collagen fibers, we believe zuCollagen is the best collagen supplement on the market. Try it out for yourself today, risk-free!

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:

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The colon is home to trillions of bacteria, both beneficial bacteria and harmful bacteria. The not-so-friendly bacteria 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, resulting in an inflammatory response. This is known as “leaky gut”.  

Leaky gut occurs anytime that blood flow to the intestines is restricted for a prolonged period of time, which surprisingly happens all the time including during exercise, alcohol consumption, and even during stress.

Glycine has been shown repeatedly to decrease gut permeability by restoring the lining of the intestines. Glycine supplies the body with the nutrients it needs to rebuild the collagen protein that is found in the gut. Since glycine can be converted readily into glutamine, 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 fort, 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. 

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.

Glycine & Inflammation:

Glycine is also believed to be the rate-limiting factor in Glutathione production, the body’s master antioxidant. The amount of glutathione your body is capable of producing is dictated by how much glycine you have available in your body. If you don’t produce or consume enough glycine then you cannot produce an optimal amount of glutathione, resulting in increased amount of oxidative stress (inflammation). 

Read More: What Are Probiotics | Probiotics Explained

Glycine & Blood Sugar:

Blood Sugar & Glycine

If you struggle with diminished energy levels, cold hands and feet, or even mood swings, your body’s ability to regulate its blood sugar levels may be out of whack. Glycine has been shown repeatedly to increase insulin sensitivity. Insulin is a hormone that “pushes” glucose into your cells from your bloodstream to be burned as fuel.  The more insulin sensitive you are, the less amount of insulin needs to be released for your cells to absorb the glucose in the bloodstream. You might imagine being “insulin sensitive” as having an efficient highway road system. Things run smoothly, so traffic never builds up and cars (glucose) can keep moving unrestricted. In contrast, being “insulin resistant” causes a huge build-up of cars. 

Glycine balances blood sugar levels by inhibiting lipolysis, the breakdown of fat cells into fatty acids in the bloodstream. This “unclogs” the bloodstream of fatty acids, as glucose and fatty acids compete with one another to enter the cell. When there are fewer fatty acids in the bloodstream  insulin can do its job much better 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 and 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 your cells from firing. 

While it’s 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 pushed to the floor. As a neurotransmitter, glycine seems to play a number of roles in the nervous system

  • Boosts Blood Flow - Glycine acts as a vasodilator providing 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.
  • Reduces Muscle Tightness - 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.
  • Improves 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 improved sleep quality.

    Glycine & The Body:

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    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. It shouldn’t come as a surprise that glycine has a ton of benefits in the body as well:

      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 a lot 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

      Best Sources Of Glycine:

      Now that we have covered the ins and outs of glycine, it's important to understand the best sources of glycine! Not all sources are created equally, so be picky and opt for the highest quality sources you can find.

      • Pig & Chicken Skin - 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

      It’s pretty clear that glycine can be seen as a pretty big deal and, given its benefits on overall health and well-being, it's rather essential  to the modern Western Diet. When we consider that about 50% of the protein in animals is made up of collagenous tissue which is a rich source of glycine, I think it’s pretty safe to say that our ancestors likely didn’t waste any part of an animal, nonetheless half 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 things that we often skimp out on today, but are rich in these amino acids. 

      zuCollagen + zuBroth

      Admittedly, a lot of the foods high in glycine are not easiest or most convenient foods to cook, so that’s we created zuCollagen and zuBroth! These are delicious and extremely convenient way of getting more glycine into your diet. Use zuCollagen in your daily smoothie or zuBroth as a seasoning or drink it as a broth to get all of the benefits of some added glycine in your daily routine!


      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