Glutamine is a conditionally essential amino acid that helps prevent muscle catabolism and boost your immune system. Some studies have even found it beneficial for treating ‘leaky gut’ and improving the health of your digestive system.
It’s the most prevalent amino acid in muscle tissue, but stores can be depleted during intense exercise. That’s why bodybuilders and athletes take glutamine to replenish these stores quicker and train more frequently.
But with so many products on the market, how do you find the best glutamine supplement for your budget?
The sports nutrition market has become saturated with hundreds of products containing L-glutamine. Some use it as the sole ingredient, others combine it with BCAAs as an ‘all-in-one’ recovery supplement, and many companies simply combine it with whey, creatine, or pre-workout stimulants as part of a protein powder blend.
By the end of this guide you’ll know which type is right for you. We’ve covered everything you need to know about the best brands, recommended intake levels, health benefits, and how to find the lowest price.
We also analyzed the ingredients from more than 50 glutamine supplements, then created a top 10 list of the best on the market. This includes products that are suitable for vegetarians and vegans.
What is Glutamine?
Glutamine is the most abundant amino acid found naturally in the body, with its primary use being the biosynthesis of proteins.
It makes up approximately 60% of the amino acids in muscle tissue, and is one of 20 naturally occurring amino acids found in dietary protein.
Glutamine is considered conditionally essential, meaning that levels in the body can drop during times of stress. Although levels would naturally return to normal, supplementation is recommended to replenish the body’s natural glycogen stores as quickly as possible.
Some of the other names for glutamine include; L-glutamine, 2-Amino-4-carbamoylbutanoic acid, and (levo)glutamide. It has a chemical formula of C5H10N2O3.
Top 10 Best Glutamine Supplements
So you want to try glutamine but don’t know which company to trust, how much you should pay per serving, or whether to buy pure glutamine of a combined glutamine and BCAA supplement.
After comparing dozens of products, right down to the cost per gram, we managed to put together a list of the top glutamine supplements on the market. We’ve also included the glutamine content of some bestselling protein powders, to make sure you don’t pay twice to get your daily dose.
Optimum Nutrition Glutamine Powder
Optimum Nutrition Glutamine is available as a powder or in capsules. The capsules deliver 1,000 mg of L-glutamine per serving, while the powder offers more flexibility over dosages and mixing.
As one of the biggest supplement brands in the industry, you can be sure of high quality ingredients. In this case the only ingredient is the L-glutamine amino acid, which helps keep costs down compared to a full BCAA supplement.
- 5 g L-glutamine per serving for powder
- 1 g L-glutamine per serving for the capsules
- GMP and NSF Certified
- Manufactured in the USA
- * Capsules contain gelatin, which means only the powder is suitable for vegetarians
Their in-house manufacturing has been registered under NSF and the Good Manufacturing Practices (GMP) Program. This means every aspect of their glutamine has been tested and approved, with regular on-site inspections of their manufacturing facilities.
Optimum Nutrition have some of the best glutamine capsules on the market, which has earned them the number 1 best seller rank in Amazon’s L-glutamine nutritional supplements category.
The glutamine powder uses the same formula, but is easier to mix with your favorite protein shake or beverage pre- or post-workout.
Body Fortress 100% Pure Glutamine Powder
Body Fortress stands up well to the product from Optimum Nutrition, and actually has the cheaper glutamine supplement. The only downside is you’re getting slightly less glutamine per serving (4.5 g with Body Fortress, 5 g with Optimum Nutrition).
- 300 g tub – enough for 66 servings
- 4.5 g Glutamine per serving
- Replenishes glutamine amino levels post-workout
- Contains no aspartame or gluten
- Designed to assist with recovery after workouts
- Manufactured in cGMP certified facilities
- Made in the USA
Body Fortress L-glutamine is manufactured according to cGMP standards, as is required by all dietary supplements.
If you’re thinking of combining their Body Fortress Glutamine with one of their protein powders, you need to be careful so as not to waste your money.
- Mass Gainer: Only contains glutamic acid, which is a component of glutamine, but they are two different amino acids.
- Whey: Contains glutamic acid as well as 3 g of L-glutamine in every 2 scoops.
- Isolate Protein: Contains a full BCAA Complex (Leucine, Isoleucine, and Valine), but no glutamine.
Bulk Supplements Pure L-Glutamine Powder
Bulk Supplements specializes in affordable, single-ingredient supplements. This is perfect for L-glutamine powder, which is available in bags ranging from 100 g all the way up to 25 kg. Vegetarian glutamine capsules can also be purchased through Amazon.
- 100 g bag at 10 g/day (2 x 5 g doses) – enough to last 10 days
- 25 kg bag at the same dose – enough to last nearly 7 years
- 1 g L-glutamine per serving
- Available in powder, gelatin capsules, or vegetarian capsules
- Free of soy, sugar, dairy, gluten, and additives
- Manufactured in cGMP facilities
- Made in the USA
In terms of price, you won’t find a cheaper glutamine supplement on the market. Even for the 1 kg bag, you’re typically looking at around $0.10 for 5 g of powder. That’s compared to $0.13 per 5 g serving if you buy the next cheapest; Nutricost L-Glutamine Capsules.
As a company, Bulk Supplements supplies over 300 nutritional supplement ingredients to hundreds of thousands of customers, in quantities up to metric tons in weight. All manufacturing takes place at their FDA-registered cGMP facility in Henderson, Nevada.
Nutricost L-Glutamine Powder
As we just mentioned, Nutricost L-Glutamine is slightly more expensive than the Bulk Supplements product, but it’s still one of the cheapest glutamine powders available. The sizes are also a little more realistic, with 250 g, 500 g, and 1 kg bottles available.
- 1 kg bottle – enough for a 100 day supply at 10 g/day
- 5 g L-glutamine per serving
- Replenishes your body’s glutamine amino acid stores
- Non-GMO and gluten free
- Made in the USA
Because of the low cost, it’s easy to combine Nutricost Glutamine with their creatine and BCAA supplements, to create an all-in-one muscle builder with higher doses than Vintage Build. Although it’s not quite as convenient due to mixing the ingredients yourself, you enjoy the same strength and muscle gain benefits at a fraction of the cost.
Although Nutricost produce dozens of health and nutrition supplements, with hundreds of highly rated reviews on Amazon, not much is known about the actual company and how they manufacture their products.
Unfortunately their tubs don’t carry the same ‘GMP Certified’ label that we see on most glutamine supplements, which is why we’re hesitant to rank them much higher on our top 10 list.
MET-Rx L-Glutamine Powder
MET-Rx has one of the few L-glutamine supplements where the serving size is 6 g instead of 5 g. At the time of writing this guide, each serving was priced at $0.18, based on buying the 1 kg tub for $30. Given that you’re getting 20% more glutamine per serving than most supplements, this is incredible value for money.
- 1 kg tub – enough for 167 servings
- 400 g tub – enough for 67 servings
- 6 g of L-Glutamine per serving
- Supports protein synthesis and replenishes glutamine stores
- No artificial sweeteners or colors
- Unflavored powder for easy mixing with creatine and protein shakes
For comparison, Optimum Nutrition was priced at $0.20 per 5 g serving (1 kg tub) and MusclePharm was also priced at $0.20 per 5 g serving (300 g tub).
Before buying MET-Rx Glutamine, it’s worth checking to make sure any protein powder you buy doesn’t already contain a serving. Many MET-Rx protein supplements also contain glutamine, such as their meal replacement drinks, Metamyosyn Protein Plus protein powder, and even their high protein pancake mix.
- Metamyosyn Protein Plus: 3 g of L-glutamine in every 2-scoop serving, as a part of their Metamyosyn® Protein Blend.
- MET-Rx Meal Replacement: 3 g L-glutamine per serving, as part of an amino acid blend that also includes over 6 g of BCAAs. Also uses their Metamyosyn® protein.
- MET-Rx High Protein Pancake Mix: Contains L-glutamine as part of their Metamyosyn® HPP Protein Blend, but the label doesn’t indicate how much. The amount of protein per pancake (18 g) is slightly less than 1 scoop of their Protein Plus protein powder, so we would estimate around 1 g of L-glutamine.
NOW Sports L-Glutamine Powder
NOW Foods is somewhat limited in the amount of L-glutamine you can buy. It’s available in just 1 tub size, weighing 454 g (1 pound), which is completely different to the range of sizes offered by Bulk Supplements and Optimum Nutrition.
- Available in 454 g tubs – enough for a 45 to 90 day supply
- Also available in 1 g glutamine capsules
- 5 g L-glutamine per serving
- Boosts digestive health and helps prevent ‘leaky gut’
- Manufactured in GMP certified facilities
- Suitable for vegetarians
- Made in the USA
In terms of the cost per serving, NOW Foods has one of the cheapest glutamine powders on the market. At the time of writing this guide, 5 g cost less than the glutamine from Optimum Nutrition (1 kg tub), MuscleTech, and MusclePharm, amongst others. One of the only companies to beat NOW Foods on price was Body Fortress.
NOW Foods produces a wide range of supplements, designed to boost your health, increase strength, and improve recovery. If you’re already taking one of their protein powders, you want to make sure you’re not doubling up on doses of L-glutamine, to avoid wasting money and ensure you control your intake.
- Whey Protein Isolate: Contains 4788 mg of L-glutamic acid per serving, and BCAAs in a near 2:1:1 ratio, but no L-glutamine.
- Pea Protein: Contains 4288 mg of L-glutamic acid per serving, but no L-glutamine.
- Whey Protein: Contains 3742 mg of L-glutamic acid per serving, as part of a 21 g dose of essential and non-essential amino acids, but no L-glutamine.
MusclePharm Glutamine Powder
Since it was founded in 2010, MusclePharm has been one of the biggest names in nutritional supplements. They now produce everything from creatine and BCAAs to thermogenic fat burners and protein powders.
- 300 g tub – enough for a 60 day supply at 5 g/day
- 5 g Glutamine blend per serving
- Blend contains L-Glutamine, glutamine peptides, and Alanyl-l-glutamine
- Aids in muscle growth and recovery
- Promotes a healthy digestive system
- Made in the USA
The big attraction with MusclePharm Glutamine powder is the price. You can usually pick up a tub for around $12, which sets the price of a 5 g serving close to $0.20. This is similar to Optimum Nutrition Glutamine, but the big difference here is that you get that value with a 300 g tub. With O.N. you have to buy a 1 kg tub to enjoy the $0.20 price per serving.
So what if you want to combine MusclePharm Glutamine with a MusclePharm protein powder? Which one is best if you don’t want to double your glutamine intake?
- MusclePharm Combat Protein Powder: Contains L-glutamine as part of their Combat Powder Proprietary Time Release System. The label doesn’t say how much, but a 34 g Growth Matrix that contains 25 g of protein leaves 9 g for BCAAs, L-glutamine, and a number of other ingredients.
- MusclePharm Combat 100% Whey: Contains no L-glutamine. This protein powder doesn’t use their time-release system, as whey protein is designed to be fast-digesting.
MuscleTech Platinum Glutamine Powder
MuscleTech Platinum Glutamine forms part of their Essential Series of supplements, with 5 g of ultra-pure micronized glutamine per serving. However, at the time of writing this guide, a 300 g tub cost around $17, putting the cost of a 5 g serving at close to $0.29.
- 300 g tub – enough for a 60 day supply at 5 g/day
- 5 g L-Glutamine per serving
- HPLC-Tested pure L-glutamine
- Flavorless micronized powder
- Replenishes glutamine amino acid stores
- Supports muscle growth and recovery
- Mixes easily with creatine and protein powders
Although this is still far cheaper than AMRAP Glutamine, it’s also around 50% more expensive than Optimum Nutrition (1 kg tub), and twice the price of Nutricost L-Glutamine (1 kg tub).
As a company, MuscleTech continues to be one of the leading bodybuilding supplement brands in America, with products distributed to over 80 countries. It’s one of the brands marketed by Iovate Health Sciences Inc., a Canadian company who were bought by Chinese food company Xiwang Foodstuffs Company Limited in 2016.
So what if you’re looking to combine MuscleTech Platinum Glutamine with one of their protein powders? How do you avoid paying twice for your daily intake of glutamine?
- Nitro Tech: Contains 5.3 g of glutamine and precursor per serving, together with 6.9 g of BCAAs (3.2 g of leucine).
- Phase 8: Contains 5 g of glutamine and precursor per serving, together with 5.6 g of naturally occurring BCAAs.
- Premium Gold Whey: Contains 4 g of glutamine and precursor, together with 5.5 g of BCAAs.
- Platinum Whey: Contains 4 g of glutamine and precursor per scoop, as part of an 11.6 g essential amino acid blend.
Jarrow Formulas L-Glutamine
Jarrow Formulas sells both glutamine capsules and glutamine powder, but if you want to get the best deal, we always recommend buying the powder. However, with Jarrow you have to be careful about how you calculate the cost per serving, as they’re one of only a few supplement companies to recommend a 2 g serving size.
As with most glutamine supplements, you don’t want to pay much more than $40 per kg. This works out at around $0.20 for a 5 g serving. At the time of writing this guide, 1 kg of Jarrow L-Glutamine was priced at $40.95, which is pretty much what we’re looking for.
- 2 g of L-Glutamine per serving
- No gluten, dairy, or soy
- Suitable for vegetarians and vegans
As with the glutamine supplements listed above, you want to be careful when buying a protein powder, so as to avoid ‘double dosing’ your glutamine. Jarrow have their own line of protein powder, and for convenience we’ve listed the glutamine content of some of their bestsellers below.
- Whey Protein: 3.06 g of glutamine and glutamic acid per 26 g serving, together with over 8 g of essential amino acids.
- Grass Fed Whey: 3.38 g of glutamine and glutamic acid per 25 g serving, together with over 9 g of essential amino acids.
- Iso-Rich Soy Protein: Contains no L-glutamine. Does contain 1.9 g of leucine, 1 g of isoleucine, and 1.1 g of valine as BCAAs.
AMRAP Nutrition L-Glutamine Powder
At the time of writing this guide, AMRAP Nutrition had one of the most expensive glutamine supplements on the market. Priced at around $33.20 per tub, this gave a cost per serving of $0.83. Compare this to something like Optimum Nutrition Glutamine, where 5 g can cost as low as $0.20, and it’s difficult for us to validate its inclusion in our top 10.
- 200 g per tub – enough for a 40 day supply at 5 g/day
- 5 g L-Glutamine per serving
- Non-GMO, gluten free
- Contains no dairy, soy, sugar, or preservatives
- Manufactured in GMP certified facilities
- Designed to support muscle growth and recovery
- Made in the USA
Glutamine is one of the most prevalent amino acids in the body, and one of the building blocks of muscle growth. But the fact is, glutamine is glutamine. There’s no added ingredient that you need to pay more for, which is why we usually expect to pay no more than $0.20 to $0.30 per 5 g serving.
If you’re able to find a 200 g tub priced closer to $10 then it’s an excellent choice. But we would never recommend paying close to $33. There simply isn’t any evidence to prove AMRAP has a glutamine powder that’s any more effective than the products where you pay under $39 for a 1 kg tub.
A few other highly rated glutamine supplements that didn’t quite make our top 10 include:
- TL Core Series BCAA Glutamine
- BSN Glutamine DNA
- EVL Nutrition GLU+
- Dymatize Nutrition Glutamine Micronized
- Betancourt Nutrition Glutamine Plus
- AllMax Nutrition Micronized Glutamine
- Kaged Muscle Glutamine Powder
- BPI Sports Best Glutamine
- GAT Essentials L-Glutamine
- Cellucor COR-Performance Glutamine
- Promera Sports Gluta-Blast
- ProSupps Glutamine 300
Who Can Benefit From Glutamine Supplements?
Glutamine can be beneficial in any situation where it becomes conditionally essential. This includes periods of intense running, weightlifting, strength training, endurance training, and even during cancer treatment, such as chemotherapy.
If you muscle tissue is in a state of repair or healing, either from traumatic injury, severe illness, or stress from physical exercise, then you should glutamine supplementation.
It can also prove beneficial to the immune system of men and women, and for maintaining healthy cells in your kidneys and intestines.
However, it’s not designed to be a solution to digestive issues, such as IBS or Crohns disease. In these situations it’s best to seek advice from a healthcare professional, who may recommend a regular course of probiotics.
How Much Glutamine Should I Take?
Bodybuilders and athletes often need far more glutamine than the body can produce naturally. But how much L-glutamine do you need, and what happens if you take too much?
Most bodybuilding and fitness sites will recommend 10 to 15 grams of L-glutamine per day, split over 2-3 servings of 5 grams each.
However, it’s not always easy to track your intake, with many pre-workout supplements, protein powders, and even multivitamin complexes including some level of amino acids.
If you’re already taking supplements, it’s worth checking the label to see if they contain glutamine. If they don’t, then you might consider taking pure L-glutamine powder or capsules.
Unfortunately there haven’t been as many well-controlled scientific studies into the dosages of glutamine, compared to supplements like creatine.
One study found no ill effect from 10-30 grams of BCAA supplementation per day. Another reported that BCAA supplementation reduced the effects of muscle damage during prolonged endurance exercise (90 min cycling bouts in this case).
Glutamine can also be found in some foods, albeit in smaller quantities.
Foods with the most L-glutamine include:
- Ricotta cheese
- Cottage Cheese
- Grass-fed beef
- Bone broth
- Wild caught fish (cod, tuna, salmon)
- Raw spinach
- Raw parsley
If you plan on taking glutamine supplements long-term, it’s worth taking a multivitamin that’s high in vitamin B12. This can help regulate the buildup of glutamine in the body.
How should I take it?
There have been no reported issues with absorbing glutamine from capsules. It really comes down to personal preference, but in our experience the powder tends to be the cheapest option, mixed with a protein shake or your favorite beverage.
When is the Best Time to Take Glutamine?
Most fitness professionals offer the same advice for when to take glutamine supplements. That is, before bed, immediately upon waking, and 30 minutes before or after exercising.
But is there any scientific evidence to back this up?
At least one study has concluded that anabolic muscle growth requires an intake of essential amino acids in the recovery period after exercise. This was found to be the best time to promote amino acid uptake into the muscle and increase the rate of protein synthesis.
A drink containing 6 g of essential amino acids and 35 g of sucrose was ingested 1 or 3 hours after exercise. Compared to a placebo drink, muscle protein synthesis increased significantly, with similar anabolic responses at 1 and 3 hours.
Some research indicates that glutamine supplementation right before bed leads to improved growth hormone levels while sleeping.
When you wake up
Even with a slow digesting casein protein, your muscles would be without key nutrients for 6+ hours. Having an early morning glutamine supplement will replenish your muscles with the most abundant amino acid at the beginning of the day.
One study noted increased HGH levels after supplementing with just 2 g of glutamine in the morning. However, the fact that the glutamine was consumed in a sugary drink, after a light breakfast meal is suspect. These are both activities that may influence GH concentration anyway, even without glutamine supplementation.
Types of Glutamine
If you read the label on most glutamine supplements, you’ll probably find it refers to L-glutamine. But you can also find glutamine peptides and D-glutamine, which is the type used by Bulk Supplements in their bestselling glutamine powder.
Health Benefits of L-glutamine Supplements
- 1. Improves gastrointestinal health
- 2. Helps heal ulcers and leaky gut
- 3. Supports cognitive focus, memory and concentration
- 4. Relieves symptoms of IBS
- 5. Promotes muscle growth and aids in protein synthesis
- 6. Improves athletic performance and recovery from endurance exercise
- 7. Improves metabolism
- 8. Curbs cravings for sugar and alcohol
- 9. Can reduce side effects from cancer treatments
- 10. Improves diabetes and blood sugar
Critical Care, Trauma and Burn Treatment
A number of scientific studies have found glutamine to be beneficial in the survival and recovery of burns victims.
Although sample sizes are often small, this is one health benefit of glutamine that has been studied for over 20 years.
In 1994, a study reported no bacterial translocation in burns victims when supplementing with alanyl-glutamine. This is a more stable form of glutamine that maintains long-term stability in solution, which can be found in MusclePharm Glutamine.
Another study in 2009 looked at the effects of enteral glutamine supplements on infections morbidity and hospital-stay in patients with burns.
Thirty patients were split into two groups, where 15 patients were glutamine supplemented until the burn was fully healed. Results showed a shorter hospital-stay for patients supplementing with glutamine, and significant reduction in positive wound culture.
A 2002 study of intensive care unit patients found similar results. In this case, the patients supplementing parenteral nutrition with l-alanyl-l-glutamine experienced a significant improvement in six-month survival compared to the control group (66.7% vs. 40%).
Cortisol and stress control
There are also a handful of smaller studies that indicate glutamine supplements can help control cortisol levels.
When the body is stressed (from injuries, infections, burns, trauma, intense exercise, or surgical procedures), it releases the hormone cortisol into the bloodstream.
Heightened cortisol levels then increase blood sugar (glucose) levels, which can be seen as catabolic due to taking the glucose away from muscle tissue. Replenishing glycogen stores is thought to shut down this cortisol increase and prevent muscle catabolism.
Treatment of peptic ulcers
According to The Encyclopedia of Healing Foods, glutamine can also be highly beneficial in the treatment of ulcers.
In a double-blind study of 57 patients with peptic ulcers, 24 took 1.6 grams of glutamine per day, while the rest used conventional therapies, such as antacids and antispasmodics. Glutamine proved to be the more effective treatment.
According to X-ray analysis, half of the glutamine patients showed complete healing within two weeks, and 22 of the 24 showed complete relief and healing within four weeks. In addition, cabbage juice, which is very beneficial in the healing of ulcers, is quite high in glutamine.
Supplemental glutamine is often given to malnourished cancer patients undergoing chemotherapy or radiation treatments, and sometimes used in people undergoing bone marrow transplants.
Glutamine seems to help reduce stomatitis (an inflammation of the mouth) caused by chemotherapy. Some studies suggest that taking glutamine orally may help reduce diarrhea associated with chemotherapy.
The same study by the University of Minnesota Medical School also suggests glutamine can protect the gut from mucositis. This is a common toxicity of cancer chemotherapy.
The maximum grade of mucositis decreased in 12 of 14 patients with glutamine supplementation, and stayed the same in the other 2.
More clinical research is needed to know whether glutamine is safe or effective to use as part of the treatment regimen for cancer.
Weight loss benefits
A number of studies have found glutamine to be helpful with the loss of body fat in overweight people. This includes a pilot study published in the European Journal of Clinical Nutrition in 2014.
In this study, 4 weeks of glutamine supplementation led to a significant decrease in body weight and waist circumference. During supplementation, patients did not change their dietary habits or lifestyle.
A separate study found glutamine to be beneficial for bypassing insulin-induced fat storage.
Controlling sugar cravings?
There’s also no shortage of fitness blog posts claiming L-Glutamine controls sugar cravings. Although glutamine is easy to convert to glucose to treat hypoglycemia, there’s no scientific evidence to show it has any effect on sugar cravings.
However, as with the benefits to cancer patients, more research is needed to clearly understand glutamine’s role in weight management.
Immune System Benefits
L-Glutamine is a conditionally essential amino acid that’s beneficial for cell growth and repair. Extensive scientific research has found glutamine metabolism to be important in repairing immune system cells after poor health, suffering an injury, or infection.
The high rate of glutamine utilization by cells of the immune system serves to maintain a high intracellular concentration of intermediates of biosynthetic pathways, such that optimal rates of DNA, RNA and protein synthesis can be maintained.
Maintenance of the immune function has also led to lower levels of infection and a shorter stay in hospital for patients supplementing with glutamine. This includes patients undergoing surgery, radiation treatment, bone marrow transportation, or suffering from injury.
By assisting cell hydration, cell volume is enhanced thereby reducing recovery time from sporting activity, injury and wounds. Muscle damage caused by intense workout or injury is repaired more effectively where the cell volume and hydration levels are aided by this very important amino acid.
Metabolism and Growth
Supplementing our intake with l-glutamine can massively increase levels of naturally occurring Human Growth Hormone (HGH). Metabolism is accelerated due to increased levels of HGH which allows the more efficient processing of foods and enhancing the efficient metabolism of fats. This leads to an improvement in fat reduction and the building of lean muscle.
Assisting Muscle Growth
The most common reason for athletes and bodybuilders using glutamine is the perceived increase in muscle growth. But are there any clinical studies to back this up?
Although glutamine is not a steroid, it’s thought that by quickly replenishing your body’s amino acid stores after intense exercise, you can boost how quickly muscles repair. This allows you to train more frequently, leading to a faster increase in strength and muscle size.
Unfortunately there is little evidence to say glutamine alone can increase strength or lean muscle mass more than a placebo. More research is needed, but two studies that disprove this theory are summarized below.
A paper published in the Journal of Strength and Conditioning Research tested the effects of glutamine ingestion pre-workout. The study size was small – just 6 resistance-trained men, where glutamine was consumed at a dose of 0.3 g x bodyweight (kg).
One hour after ingestion, 3 groups performed 4 total sets of exercise to muscular failure. Based on this small sample size, measured after one training session, with just 4 sets of exercise, researchers concluded glutamine does not enhance weightlifting performance.
In our opinion, this should hardly be considered a trustworthy study, due to the small sample size and limited duration.
A second, larger study was performed a year earlier, whereby the strength of 31 subjects consuming glutamine was measured against a placebo group for a period of 6 weeks. Again, researchers concluded that glutamine supplementation during resistance training had no significant effect on muscle performance.
The problem here is that rate of recovery was not measured, and the same training schedule was maintained by the glutamine and placebo groups. Also, as we know, creatine is the supplement to take if you’re looking for strength gains.
What to Look For in a Top Glutamine Supplement
When we review the latest glutamine supplements, there are a few features we’re always looking out for.
Because they’re single-ingredient products, comparisons are much easier than something like a probiotic or protein powder. This means it really comes down to 5 key factors:
- 1. Cost per gram: Calculating the cost per serving is useful, but it has its limits.
What if one product has a serving size of 3 g and the other product a serving size of 5 g. It’s always best to perform a quick calculation to find out the cost per gram, for all container sizes if possible.
- 2. Brand reputation: We always feel more comfortable buying from a well-established nutritional supplement company. This doesn’t mean they need decades of research and hundreds of products, but it helps if you can find a large number of positive reviews from real customers across a number of their supplements.
- 3. Certifications: These can be an indication that the quality and quantity of ingredients on the label are accurate. You should look for the stamp that says a product is NSF certified or cGMP certified, and ideally both.
- 4. Amount of glutamine per serving: We’re usually looking for supplements with 3 g to 5 g of glutamine per serving. This is based on a combination of clinical studies found during our research for this guide, and anecdotal evidence on bodybuilding and fitness forums.
- 5. Container sizes and discounts: Most supplement brands produce glutamine in a range of different sized tubs. But we wouldn’t recommend simply buying the largest tub you can. Try to find a balance between value for money and practicality (how much you will realistically consume in a year, for example).