Everyone would like to be at a healthy weight throughout their lives. Diets, fasting, and supplements are all common tools people use around the world to try and lose weight and keep it off. But, what if there was something else you could try that's been proven to work? If you've never heard of L-Glutamine for weight loss, this is for you. We're going to cover five science-backed reasons why you should use L-Glutamine to lose weight.
Glutamine is an essential amino acid that plays a critical role as one of the building blocks of protein. (1) Glutamine amino acids perform many functions throughout your body, and they come in two forms. Those two forms are:
D-Glutamine and L-Glutamine are almost 100% identical in what they do, but they differ in their molecular structure. The one that has the most influence on weight loss is L-Glutamine since its main function is to produce proteins. L-Glutamine also helps keep your immune system functioning and your digestive tract healthy.
You can find this amino acid in the food you eat and in supplements. However, sometimes manufacturers use Glutamine instead of L-Glutamine to hide the source of the product or the bioavailability. Your body also produces L-Glutamine naturally, and you can find it in your blood and bodily fluids. (4)
So, why do we need supplements if L-Glutamine is already present in our bodies? What happens is that, sometimes, your body can't produce enough L-Glutamine, which is where supplements come in. Situations in which your body can't produce enough of this amino acid include things like injuries and certain chronic medical conditions or illnesses. Plus, it is also a good idea to consume supplements when need to increase the amount of L-Glutamine in your body to fight issues like leaky gut, poor exercise performance, IBS, sugar cravings and more. (5)
For people who want to try and increase their L-Glutamine intake through food, there are several options (6):
- Beef - 4.8% (1.2 grams of L-Glutamine in 100 grams)
- Corn - 16.2% (0.4 grams of L-Glutamine in 100 grams)
- Eggs - 4.4% (0.6 grams of L-Glutamine in 100 grams)
- Skim Milk - 8.1% (0.3 grams of L-Glutamine in 100 grams)
- Tofu - 9.1% (0.6 grams of L-Glutamine in 100 grams)
- White Rice - 11.1% (0.3 grams of L-Glutamine in 100 grams)
5 Reasons to Try L-Glutamine For Weight Loss
Firmicutes are the main category of bacteria in your digestive tract. They're waging a constant war with your cells on what happens to the food that enters your system. The Firmicutes want to absorb as many nutrients as they can from the food you eat. This puts them at odds with your cells because your cells are also trying to absorb these nutrients and use them throughout your body for fuel. (7)
Bacteroidetes are the other large class of bacteria in your digestive tract. They're fighting with the Firmicutes over food. The ratio of Bacteroidetes to Firmicutes in your system is a biomarker for obesity. Studies show that having a significantly higher level of Firmicutes in your system can lead to weight gain or trouble losing weight. This is due to the bacteria eating and absorbing a higher calorie count from the food you eat. (8)(9)(10)
Knowing this, how does L-Glutamine promote weight loss and help to reduce the number of Firmicutes and balance the two classes of bacteria? The answer is simple: L-Glutamine plays an essential role in helping to regulate the number of bacteria present in your digestive tract.
One of the biggest things L-Glutamine does to help fix the ratio of Firmicutes and Bacteroidetes in your system is to increase the levels of Bacteroidetes. In turn, this helps to stop the Firmicutes from taking over, and it can decrease the number of calories your body absorbs.
One study took 30 overweight adults and split them into two groups. Group A got a supplement consisting of 30 grams of L-alanine. Group B got 30 grams of L-Glutamine for two weeks. At the end of the study, Group B had a significant increase in the ratio of Bacteroidetes (good bacteria) to Firmicutes (bad bacteria) in their system that went from 0.85 to 0.57. Group A had had an increase of the Firmicutes from 0.91 to 1.12. (11)
Other studies show that the Bacteroidetes family can also help to suppress the release of GLP-1. This is a hormone that helps reduce your appetite, and it can also help you burn calories from fat. Additionally, they can help regulate how quickly food goes through your system. This can stop your body from absorbing as many calories as it would if your body didn't push the food you ate along at a steady rate. (12)(13)
All of these things can contribute to healthy and steady weight loss. It can also contribute to keeping the weight off once you manage to lose it.
For years, L-Glutamine has helped overweight people burn weight and improve their lean body tissue. Lean body tissue refers to many essential parts of your body, and this includes your bones and organs. Ligaments, tendons, and muscles are also categorised as lean body tissue because there is typically very little fat around these areas in people who are at a healthy weight. (14)
However, these areas aren't completely free of fats because there are essential fats that are always present in your organs and bones. People who are overweight have larger amounts of unnecessary fat around their lean body tissue. L-Glutamine can help to change this.
L-Glutamine may promote fat burning throughout your body, even without exercise or lifestyle changes. Studies show that overweight women who took an L-Glutamine supplement experienced weight loss even when they didn't change their diets or exercise routine. They split 20 women into two groups and gave one a protein supplement, and one an L-Glutamine supplement. At the end of four weeks, the group that got the L-Glutamine supplement had decreased waist circumference and weight loss over the control group. The same study also showed that L-Glutamine can improve your body's insulin sensitivity. (15)(16)
L-Glutamine can help to increase your lean body tissue because it enhances your cell volume and increases your muscle tissue's hydration levels. This means that your muscles can perform better for longer periods and you won't feel as fatigued as quickly. (17)
A second study took 31 patients with heart failure and put them in a double-blind, placebo trial. One group got a supplement consisting of L-Glutamine and polyunsaturated fatty acids, and the other group got a placebo. At the end of the trial, they found that the group of people who had gotten the supplement with L-Glutamine had significantly increased lean tissue growth around their heart and organs. (18)
A third study took slightly overweight aging adults and added L-Glutamine-rich whey protein to their diets. They received this daily for five weeks. At the end of the five weeks, they found that the study's participants had increased lean body tissue and decreased weight. (19)
The pituitary gland secretes a proteohormone called Human Growth Hormone (HGH). This growth hormone is responsible for the growth spurts children go through. It has many other functions throughout your body like regulating your body's composition, muscle and bone growth, fat and sugar metabolism, and your bodily fluids. (20)
Since the growth hormone helps to regulate your metabolism, it can also indirectly help to regulate the levels of fat your body stores. One promising study took 24 obese participants and split them into two groups. One group got a placebo, and the other group got a small dosage of HGH. At the end of the 12-week trial, they found that the group who had the growth hormone supplement lost 1.6x more weight than the control group. (21)
L-Glutamine is a critical component when it comes to regulating the pituitary gland's output. Since L-Glutamine is the most abundant amino acid present in your blood, it makes sense that it's a key player in HGH secretion.
It's important to note that the natural secretion levels of human growth hormone tend to start to decrease after age 30. L-Glutamine can encourage your pituitary gland to secrete more than it normally would. Even taking two grams of L-Glutamine can increase your body's natural levels of HGH by up to 76%. (22)(23)
This is extremely important because the human growth hormone plays a role in weight loss. When you're overweight, your body's ability to produce enough human growth hormone is severely impaired. Since L-Glutamine is a natural way to increase the levels of HGH in your blood, it can help offset the impairment. In turn, you can start to lose healthy amounts of body fat while increasing your lean body tissue. (24)(25)
Raising your levels of human growth hormone is a good way to start losing weight if you've hit a plateau because it prompts your metabolism to work hard. As your metabolism gets faster, you'll start to burn fat at a more rapid pace. Additionally, the extra fat will go from being stored in your system to being burned by your muscles. (26)(27)
Non-alcoholic fatty liver disease (NAFLD) is a serious medical condition where excess amounts of fat build up around your liver, and your liver stores it directly. It's the most common type of liver problem in the United States. It's very common in people who are obese and in people who have other medical conditions like Type II Diabetes. (28)
Taking an L-Glutamine supplement can help slow the progression of non-alcoholic fatty liver disease because it fights inflammation and helps to repair cell damage. Chronic inflammation of the liver is a hallmark sign of this disease. L-Glutamine goes to work on a cellular level, and it can help to reverse the damage of inflammation and oxidative stress. In turn, your liver can start to function at a better rate. (29)(30)
One study with mice took two groups and gave one group a supplement of L-Glutamine along with their diets. The second group received diets without L-Glutamine for 13 weeks. At the end of the 13- week study, the mice who got the L-Glutamine supplement showed less damage to their livers as a whole. (31)(32)
Additionally, L-Glutamine helps to keep the amount of fat any organ in your body stores low. It can help your body burn this excess fat by directing it to your muscles. When it does this, your liver doesn't have time to build up a large storage of fat. This can result in lower overall fat content in your liver, and your liver can start to heal. (33)
One of the markers of non-alcoholic fatty liver disease is chronic inflammation that can eventually lead to damage on a cellular level. While it doesn't directly counter the inflammation, it can help to reduce the number of inflammatory markers in and around your liver. Once the inflammation starts to go down, your liver cells can start to repair any damage. Eventually, your liver will be able to work better as it heals. (34)(35)
You may or may not have heard about Leaky Gut Syndrome or intestinal permeability. Leaky Gut is a medical condition where you have small cracks or holes in your intestinal lining. These small cracks or holes allow bacteria that thrive in your intestines to move from your intestines and into your body. Your body sees this as an infection, and it sends an inflammatory response to try and stop it. Since the bacteria can go throughout your body, you end up with system-wide inflammation. (36)(37)
This low-grade inflammation can interfere with dozens of natural processes and systems in your body, and it can lead to chronic health problems. You can also end up with extensive damage at a cellular level that can last for years. (38)
One way L-Glutamine can help to remedy this intestinal permeability is by forming a thin barrier between your intestinal wall and the bacteria that thrive in your digestive tract. It'll coat the walls of your intestines. This allows for the cracks and fissures to slowly start to heal. As they heal, the inflammation can start to go down. (39)(40)
This what Michelle B. experienced after using L-Glutamine to heal her gut and lose weight:
L-Glutamine also has powerful anti-inflammatory properties associated with it. It's an excellent way to help heal your systems at a cellular level because it helps to give essential nutrients to the cells. It's also critical to note that chronic inflammation has strong links to obesity and the ability to lose weight. (41)
Studies show that people who have chronic inflammation have difficulty losing weight. This can be due to problems with their insulin resistance, metabolism, or how effectively their body extracts the nutrients from the food they eat. (42)(43)
Since insulin acts as a regulatory agent for many bodily processes, it's important that your body has good levels of insulin resistance. If it doesn't, your pancreas can make far too much of it. This leads to problems with your blood sugar, intestines, liver, heart, and skeletal system. (44)
L-Glutamine works to help improve your cells' sensitivity levels to insulin. Studies show that giving someone who has Type II Diabetes supplements of L-Glutamine can reduce the levels of insulin in their blood, reduce body fat, and encourage smaller waistlines. Diabetics who take L-Glutamine also have reduced blood pressure. (45)
Losing weight can be a struggle unless you have all of the tools you need to accomplish it successfully. You do want to consult your physician before you start to take any new supplements or implement any drastic lifestyle changes.
However, these five science-backed reasons why L-Glutamine is a good option for weight loss should help you understand exactly why it's such a popular supplement for weight loss. If it fits into your lifestyle and if your doctor approves it, you may want to try adding it and seeing if it improves your life. You could be happier and healthier just by adding it to your diet.
Editor's note: Originally posted on February 22, 2019. Edited and updated on April 11, 2022.