Best Glutamine Supplement

Discover if a supplement of the body’s most abundant amino acid can improve exercise, immunity, gut health, or weight loss.

Medically reviewed by:
Last updated: Feb 29th, 2024
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Best Glutamine Supplement

Amino acids, the building blocks of proteins, play a role in several of the most prominent enzymatic reactions in the body. As such, proper intake of amino acids, or lack thereof, is associated with major health issues in our society, including obesity, insulin resistance and diabetes, gut health, and immunity. If you’re trying to address any of these concerns, supplementing with certain amino acids may help. One particular amino acid — glutamine — seems to play a role in many of these areas.

Glutamine helps your body synthesize proteins and may help you build muscle, recover faster from exercise, boost your immune system, improve your gut health, and speed up weight loss. Scientific research shows that many of these claims have promise, while some still require more research.

Our guide breaks down the features of glutamine supplements and provides our top picks based on cost, quality, and effectiveness. Keep reading to discover if a glutamine supplement is right for your health journey. If you’re in a hurry, check out our top recommendations:

Summary of recommendations

Our Top Choice

Revive's glutamine supplement offers a higher strength, allowing for a 10g dose with the same amount of powder used for 5g in other brands.

Revive is gluten free, third-party tested, and mixes extremely well into plain water. The company is also transparent about their testing results, which are publicly available. Take up to 15% off when you select a subscription on Amazon.

Table of Contents

In this Review

Why you should trust us

At Innerbody Research, we extensively test each health service or product we review, including glutamine supplements. It starts with research, and our team has devoted several hundred hours of research to amino acid supplements and their potential benefits for health, from improving gut linings to bolstering cognition and building muscle. All told, we’ve read more than 100 scholarly articles on the topic, many of which dealt with glutamine, in particular.

After the research phase, we found what we thought were the best glutamine products on the market and tried them for ourselves. A small testing team isn’t a scientific study, but it allows us to give you an honest accounting of these products’ taste, mixability, and apparent efficacy. It also lets us report on these companies’ support systems, their shipping logistics, and the overall customer experience.

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy. We’ll continue monitoring glutamine supplement developments for new products and science to keep this guide up-to-date.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

How we evaluated glutamine supplements

Best glutamine supplements

Photo by Innerbody Research

To evaluate glutamine supplements, we focused on several criteria that get to the heart of what a consumer might need or want from them. We place effectiveness at the top of this list, and it carries the most weight in our considerations for nearly every supplement category we review. Safety is a close second to efficacy; while glutamine as an ingredient typically presents the same degree of safety across brands, there are several other factors that may make one choice safer than another.

Finally, it’s important to look at cost and customer service, the latter of which encompasses things like support infrastructure and shipping logistics. These factors have less of an impact on our final regard for a given company, but they can be what sways your decision one way or the other.

Let’s take a closer look at each for more clarity.


Winner: Revive Glutamine

Glutamine supplements present an interesting situation for evaluating efficacy. In some cases, more glutamine is better. Studies have shown that it’s tolerable in doses of up to 30g/day. There has also been substantial research that illustrates glutamine’s effectiveness at bolstering the intestinal lining against leaky gut syndrome for individuals who need to undergo major surgeries — which typically weaken tight endothelial junctions integral to gut health.

From a gut health and immunity standpoint, Revive easily takes the win for effectiveness, thanks to the fact that its dose is double that of its competitors. It’s not just a matter of the company telling you to take twice as much as those competitors, either; scoops of Revive that are relatively equal in size to those from competitors contain double the amount (10g as opposed to 5g). Revive produces a mixture that’s easier to make and easier to drink despite using a similar quantity of powder.

We consider Transparent Labs a solid runner-up in this category, particularly for those hoping that glutamine will help as a workout supplement. Transparent Labs BCAA Glutamine may only contain the same 5g of glutamine found in many other brands, but it also has 8g of branched-chain amino acids (BCAAs), which can improve exercise performance, reduce muscle soreness, and positively impact muscle protein synthesis. This product from Transparent Labs is at the top of our guide to BCAAs for women and is one of our top recommendations for amino acid supplements in general.


Winner: Transparent Labs

When taking any dietary supplement, it’s essential to pay attention to the steps the company takes to ensure its product is safe. Since the Food and Drug Administration (FDA) does not regulate supplements the same way as food and prescription drugs, it’s important to consider a company’s manufacturing, storage, testing, and shipping practices to ensure you’re buying a pure product. Most supplement companies are transparent about these processes and include details on their websites.

Our winner in this category is Transparent Labs. Its glutamine supplement is third-party tested (like all our other top picks), vegan-friendly, and free of most allergens. In comparison, Revive Glutamine is vegan-friendly, soy-free, gluten-free, and contains no artificial colors.

Transparent Labs makes its third-party testing results available on its website, so you can see how your specific batch performed. And another thing the company does to illustrate its commitment to safety and transparency is list the exact quantities of the supplement’s “other ingredients.” You’ll usually only see doses for active ingredients in nutritional supplements (and if a company uses proprietary blends, you won’t even get that information). But, uniquely, Transparent Labs lists the doses of each component, right down to the stabilizers it uses to extend a product’s shelf life.


Winner: Kaged

Comparing one glutamine supplement’s pricing to another’s requires a little bit of math. That’s because many of these companies deliver their supplements with varying numbers of servings. Most offer 5g doses, but you could get as few as 30 and as many as 100 servings from a single container, depending on who’s selling it.

We consider Kaged to be the winner for cost because its container offers 100 servings at a better price per gram than anyone else. And that’s before taking its potential subscription savings into account. If you sign up for automatic shipments, you’ll pay around $0.22 for each 5g serving.

Kaged is also one of three companies on our list to offer additional discounts for military personnel, teachers, students, and first responders (the other two companies being Onnit and Revive). Once you verify your status, you’ll be able to get 20% off any Kaged order up to once per day. Onnit’s discount, in comparison, is 15% and Revive’s is “up to 20%.”

Customer service

Winner: Kaged

Our customer service evaluation takes a handful of things into account, including:

  • Website design
  • Shipping times and tracking
  • Customer support contact options
  • Free programs and advice

Considering all of these, Kaged edged out its competitors. Its shipping speed was matched only by Onnit’s, and while both companies provided order confirmation, shipment confirmation, and out-for-delivery notifications, only Kaged added the final delivery notification to its communications.

Kaged also provides free workout guidance on its website, including 12-week workout programs designed for various goals that take you through proper form and provide motivation to use its supplements to the fullest.

How our top recommendations compare

The sticker price for most glutamine supplements appears pretty similar at first glance, but subtle differences in serving size and serving count can make a big difference in long-term costs. And with so many other factors to consider, from return policies to available flavors, we thought a handy chart would be helpful:

Transparent Labs
Bulk Supplements
Kaged Glutamine
Single purchase cost
$22 (for 250g)
Number of servings
Serving of glutamine
Price per gram of glutamine
Return policy length
15 days (but you get a Revive gift card, not money back)
90 days
30 days (items must be unopened for refund; store credit will be issued for opened products)
30 days
60 days
Money-back guarantee?
Free shipping threshold
Sour green apple, tropical punch, strawberry lemonade, and blue raspberry

Note: Transparent Labs also includes an 8g serving of vegan BCAAs in a 2:1:1 ratio, and it tops our rankings for BCAA supplementation.

Special Offer: Take 15% of Revive with a Subscription

What is glutamine?

Glutamine is an amino acid that aids in synthesizing proteins. In addition to building muscle, proteins help keep organs functioning and help the body fight off infection, among other things that keep us alive. The body naturally produces glutamine, which makes it a nonessential amino acid (compared to the nine essential amino acids that the body can only get from dietary sources). But glutamine is also considered to be within a subgroup of nonessential amino acids that the body sometimes needs to consume in order to maintain sufficient quantities. These are considered conditionally essential amino acids and, in the case of glutamine, may be prescribed for those undergoing chemotherapy or recovering from surgery.

There are two forms of glutamine: L-glutamine and D-glutamine. D-glutamine is not essential to body processes, so you’ll often see supplements that include L-glutamine, the form humans need for overall health. L-glutamine is the bioavailable form, meaning that it’s the kind that you can digest and use most easily. Often it is just referred to as glutamine. (All of our top picks are in the form of L-glutamine.)

There’s also an acetylated form of glutamine called N-acetyl L-glutamine (NAG). This is a more stable form of glutamine that boasts superior solubility in water, but research is conflicting as to whether it's more or less effective than L-glutamine. Some NAG studies show increased absorption, while others see only an increase in the output of urinary metabolites that indicate malabsorption. For now, we prefer L-glutamine, but we would recommend Bulk Supplements as a source of NAG if you’re more interested in that.

In addition to helping with recovery from illness or injury, such as by potentially reducing the length of hospital stays for cancer patients, glutamine may also help in other ways, including (but not limited to):

  • Building muscle
  • Reducing exercise recovery time and improving feelings of well-being in athletes
  • Supporting immunity
  • Enhancing intestinal health (and potentially helping symptoms of IBS and ulcerative colitis)
  • Reducing oral inflammation from cancer therapy
  • Inhibiting colon cancer cells when combined with thiosemicarbazide in silver nanoparticles
  • Promoting weight loss

While glutamine’s importance to immunity and intestinal health has been shown through scientific research, more research must be done to affirm its role in muscle building and weight management. Nonetheless, it’s a popular pre- and post-workout supplement ingredient.

Most people can obtain glutamine from a balanced diet, with particularly good sources being foods high in protein. Here are some foods that contain glutamine:

  • Eggs
  • Beef
  • Skim milk
  • Tofu
  • White rice
  • Corn

But if you have certain leaky gut symptoms or you want to try taking your work in the gym to another level, you may benefit from supplementing with glutamine. There is no specific amount of glutamine that you should ingest per day, mainly because it’s an amino acid that your body already naturally produces. However, some clinical studies have noted doses between 5 and 45g per day without severe side effects. Essentially, the amount of glutamine you take daily depends on your desired outcome, the product’s serving suggestions, and your doctor’s recommendations.

Insider Tip: Glutamine has nothing to do with gluten, so those who live with celiac disease or maintain a gluten-free diet are in the clear. Just be sure to make sure the supplement you choose is completely gluten-free, as there may be ingredients in addition to glutamine that do contain gluten.

How glutamine supplements work

Glutamine supplements work by boosting your body’s glutamine levels and helping it synthesize proteins more effectively. This can accelerate muscle and tissue repair and fight illness and infections. Other fitness-related uses for glutamine include muscle building, exercise recovery, and weight loss. While these claims require more clinical research, preliminary studies reveal promising results.

Read on to discover how glutamine supplements may be able to improve your health.

Immunity and recovery

Glutamine appears to help boost the immune system. There is a wealth of research that’s been conducted on this potential link, but we’ve highlighted some important studies below:

  • One review found that glutamine is a crucial immunonutrient that can help people recover from illness or injury faster.
  • Another review found that patients recovering from bone marrow transplants who were given glutamine-supplemented diets experienced lower levels of infection than patients who ate a standard diet.
  • An older clinical trial from 2009 found that administering a glutamine-enriched diet to patients after abdominal surgery lowered incidences of infection and shortened hospital stays.
  • Several animal studies show that glutamine boosts the immunity of animals with viral infections.
  • Unfortunately, a 2023 systematic review found that glutamine supplementation did not lead to improved healing or clinical outcomes in adult patients suffering from severe burns.

Intestinal health

Glutamine can help boost intestinal health, particularly by addressing issues stemming from a leaky gut. Since intestinal health is linked to immunity, quieting a leaky gut is another way that glutamine can support immune health.

One review found that glutamine may help protect and repair the gut when it's under stress, while others found that glutamine can help with IBS, ulcerative colitis, and intestinal permeability (the clinical term for leaky gut). And another separate study on rodents found that glutamine reduced intestinal permeability after a bile duct blockage.

Muscles and exercise

Glutamine is a popular ingredient in pre- and post-workout supplements. It’s easy to assume that glutamine facilitates muscle building because it helps synthesize protein. However, clinical testing of this hypothesis has not supported it. For example, in one trial, participants took glutamine supplements for six weeks while weight training and showed no significant muscle gain or performance changes. Other similar studies have shown comparable results.

On the other hand, some clinical trials have shown that glutamine supplementation can help reduce muscle soreness after exercise, potentially leading to improved exercise recovery. For example, one trial showed that male participants experienced improved muscle recovery and soreness after supplementing with glutamine and performing knee extensions.

Additionally, a small 2024 study on 21 combat-sport athletes found that supplementation of L-glutamine after intensive training led to an increased testosterone and cortisol ratio, as well as a reduction in upper respiratory tract infections. Researchers ultimately suggested that L-glutamine could be beneficial for “the sports performance and recovery of athletes.”

Weight loss

As with muscle building, glutamine’s effect on weight loss is still inconclusive and requires more testing. However, some studies have shown encouraging results. One trial involving female patients with overweight or obesity found that supplementing with glutamine for four weeks led to lower waist circumference and body weight.

Are glutamine supplements a good choice for you?

Glutamine supplements - Kaged, Revive, and Transparent Labs

Photo by Innerbody Research

Glutamine supplements may be a good choice if you’re interested in boosting your immunity or intestinal health. It could also be a good option if you’re recovering from an injury, illness, infection, or other condition that depletes your body’s natural ability to produce glutamine.

For example, glutamine supplementation is often used to help those living with cancer. Glutamine supplementation can lessen one of the severe side effects of chemotherapy called mucositis, which affects the intestines and causes inflammation and sores in the throat and mouth. If you’re experiencing these symptoms during cancer treatment, speaking with your doctor about glutamine supplementation would be a good idea.

Glutamine supplements may also be a good choice if you are interested in building muscle, speeding up exercise recovery, or losing weight. And even though clinical research about glutamine’s impacts is still inconclusive, user testimonials of many glutamine-based products indicate that they can be effective as pre- and post-workout supplements.

Who should avoid glutamine supplements?

Some health conditions may be exacerbated by glutamine supplementation. It’s important to talk to your doctor before beginning any new supplement, as qualified healthcare practitioners have the best knowledge of any potential contraindications. Still, if you are living with any of the following conditions, it’s best to avoid added glutamine:

  • Kidney disease
  • Liver disease
  • Reye’s syndrome
  • Seizure disorder
  • Psychiatric disorders

This supplement can also interact with some medications, like lactulose. Even though some trials have shown that glutamine supplementation can help with chemotherapy side effects or possibly work with other ingredients to inhibit certain cancer cells, other clinical research shows that it may increase tumor production. If you’re living with cancer (or are at risk for cancer), talk to your doctor about whether glutamine is safe for you.

If you are elderly, you should actually reduce your intake of daily glutamine. And you should also avoid glutamine supplements if you are pregnant or breastfeeding. Although glutamine supplementation has been used to care for infants and children, consult with a pediatrician before giving them to anyone under age 18.

Are glutamine supplements safe?

Glutamine supplements are generally safe to take for most healthy adults who aren’t pregnant or breastfeeding. Studies have illustrated glutamine’s tolerability in doses with strengths up to 45g/day, and most supplements contain 10g per dose or less.

Be aware that some people are allergic to glutamine and may experience side effects, like:

  • Nausea
  • Vomiting
  • Joint pain
  • Hives

If you experience these symptoms after taking a glutamine supplement, seek immediate medical attention and discontinue use.

Daily intake of a glutamine supplement can also result in some mild side effects like bloating, dizziness, upset stomach, or heartburn. If you experience these, lower your dosage or consider stopping supplement use.

The jury is still out concerning the safety of taking glutamine supplements long-term. Most clinical studies administer the supplement for only a few weeks, so we do know that short-term use is considered safe up to about 45g per day, with 5g per day being a more sustainable amount. Since more research needs to be done about the long-term effects, it’s important to stay informed about scientific developments as they happen if you plan to take glutamine for longer than a few weeks.

And, as always, we recommend speaking with your doctor before starting any new supplement, including generally safe ones like glutamine.

Revive Glutamine

Best overall and best high-dose

Revive Glutamine

Photo by Innerbody Research


  • High 10g dose of glutamine per serving
  • Third-party tested for purity, safety, and dosing accuracy
  • Testing results are publicly available
  • Formula is gluten-free, soy-free, and vegan-friendly
  • Up to 15% off with a subscription from Amazon


  • Third-party test results are available, but the upload is blurry and hard to read
  • No money-back guarantee
  • Strict 15-day return policy
  • Subscriptions when buying direct offer no savings

While most companies seem content to provide a 5g serving size for their glutamine supplements, Revive doubles that dose. In most studies we’ve reviewed, 5g is the low end of what scientists investigate as a potentially effective dose. There are some benefits to be had there, but a 10mg dose is closer to those that have been shown to be most effective.

You might ask yourself whether it would be smarter or more economical to just buy a budget supplement with a 5g serving size and double the dose yourself. And that’s not a bad way to get to 10g. But when you look at the scoops that come with these supplements and compare their actual volume, you’ll see that Revive gets a 10g dose out of a nearly identical amount of glutamine powder you need for 5g of its competitors’ products. That becomes important when it comes to the practicality of mixing; a higher strength at the same powder volume allows you to mix Revive’s glutamine powder into something like plain water without as much clouding or as intense of a taste at the 10g dose.

Like many glutamine supplements, L-glutamine is Revive Glutamine’s only ingredient.

Taste and mixability

Revive Glutamine mixed

Photo by Innerbody Research

Revive Glutamine mixes very well into plain water, though it will turn the water a milky white color. It doesn’t settle out much once you’ve mixed it in, and our testers found they could almost entirely mix it with water just by swirling the glass, taking it the rest of the way with a spoon. Considering that milkiness and the typically abhorrent taste of BCAA and EAA supplements, you may not have high hopes for glutamine in general. But we find that this product has a very mild taste that you can obscure with something like a splash of fresh lemon juice or by mixing it into an electrolyte-rich beverage like Gatorade.


We often recommend purchasing products directly from supplement companies to take advantage of unique perks like subscription deals, but Revive is one of the cases where we’d say buying from Amazon is definitely your best bet. Unfortunately, Revive doesn’t offer a subscription deal — both one-time purchases and subscriptions cost the exact same. In the chart below, we break down the pricing from both Revive and Amazon.

One-time purchaseSubscription
Purchasing direct$19.99 ($0.67 per serving)$19.99 ($0.67 per serving)
Amazon$19.99 ($0.67 per serving)$17.99 ($0.60 per serving)

Even if you only want one container, you can still subscribe on Amazon and cancel it right after the product ships.

Shipping from Revive directly is only free for orders of $150 or more; for orders under $150, UPS Ground is your only option, and it’s calculated at checkout. And shipping from Amazon is free on orders over $35 (so subscribing and buying two containers would get you over the threshold).

Revive only gives you 15 days to return a product, and it has to be unopened. No matter the situation, if Revive approves a return, your refund is only given as a gift card to use on its site. This is the weakest aspect of Revive’s service, as competitors like Onnit offer actual money-back guarantees that give you a chance to try the product before sending it back. We hope to see Revive improve its customer service in the future to meet the standards set by competitors.

Transparent Labs BCAA Glutamine Powder

Best pre-workout

Transparent Labs BCAA Glutamine mixed

Photo by Innerbody Research


  • Contains 8g of vegan BCAAs for improved exercise performance
  • Includes vitamin C for immunity and gut support
  • Coconut water powder may boost hydration and help with renal health
  • Four flavor options
  • No artificial sweeteners or colors
  • Subscribing can unlock free shipping and save 10%


  • Pricier than other options
  • No money-back guarantee
  • Flavors limit mixing options

Transparent Labs BCAA Glutamine Powder is our top pre-workout because it boosts your muscle-building potential by combining the power of glutamine with BCAAs. Those specific amino acids — leucine, isoleucine, and valine — have been shown to potentially reduce muscle soreness after a workout and balance muscle protein synthesis against protein breakdown to ensure you maintain the muscle you have and increase the odds of building more.

In addition to glutamine and BCAAs, the supplement also includes coconut water powder, which can help with hydration and electrolyte balance and may also play a role in kidney health. There is some evidence that amino acid supplementation can negatively impact the kidneys and even lead to the development of kidney stones. But coconut water powder has shown potential in working against this. Rounding out the formula is vitamin C, which works hand-in-glove with glutamine’s gut support. While glutamine works to bolster and repair gut linings, vitamin C can help balance out the gut’s microbiome.

Transparent Labs provides comprehensive ingredient lists to consumers. That’s why its ingredient breakdown includes specific measurements for its “other ingredients,” something we’ve yet to see from any competitor.

Active ingredients

  • L-Leucine: 4,000mg
  • L-Isoleucine: 2,000mg
  • L-Valine: 2,000mg
  • L-Glutamine: 5,000mg
  • Vitamin C: 1,535mg
  • Coconut water powder: 1,000mg

Other ingredients

  • Citric acid: 2,000mg
  • Natural flavor: 1,600mg
  • Stevia: 515mg
  • Calcium silicate: 257.5mg
  • Silicon dioxide: 257.5mg

Taste and mixability

Because it contains BCAAs, an unflavored version of Transparent Labs BCAA Glutamine would not be very pleasant to drink, so the company provides four flavor options, more than any other product on this list:

  • Sour green apple
  • Tropical punch
  • Strawberry lemonade
  • Blue raspberry

Our testers tried the tropical punch flavor, and it scored around the middle of the pack among other BCAA supplements. Compared to unflavored glutamine supplements, the added taste is a double-edged sword. On the one hand, you get a product that you can easily mix with water and enjoy before, during, or after a workout. On the other hand, your mixing options are more limited than they would be with unflavored glutamine. As for mixability, BCAA Glutamine blends well enough with water, though there is some slight settling out at the bottom of the glass after a while. This is mostly a result of its other ingredients; plain, unflavored glutamine tends to mix better with water, as our testers experienced with Revive’s glutamine, for example.


One tub of powder costs $39.99, which includes a 30-day supply. You can earn free shipping by placing an order over $99 or by subscribing for repeat deliveries. Unlike buying directly from Revive, joining Transparent Labs’ subscription program saves you 10% on each order ($35.99/tub). Here’s what those subscription savings can look like:

CostCost per servingShipping
One-time purchase$39.99$1.33$9

You can choose to have your order auto-shipped every 30, 45, or 60 days.

Transparent Labs offers a 30-day return policy on unopened products for a full refund. If your product is opened, you can still return it within 30 days for a store credit or product exchange.

Kaged Glutamine

Best budget pick

Kaged Glutamine mixed

Photo by Innerbody Research


  • Lowest cost per gram of glutamine on our list
  • 100 servings per container
  • Third-party tested
  • Informed-Sport certified
  • Flexible delivery schedule for subscriptions
  • 60-day satisfaction guarantee and return policy
  • Subscribing gets you free shipping and 10% off


  • Frequently sold out
  • Testing results are not readily available
  • Doesn’t taste or mix as well as other unflavored options

Often, when we set out to review supplements, we find that Bulk Supplements (a little further down our list) often comes out ahead of the pack in terms of cost. But in the case of glutamine, Kaged managed to edge it out by delivering its product at a lower one-time cost and offering a deeper discount to subscribers.

From a dosage perspective, you could easily titrate up from 5g if you feel you’re not getting results at that level, and the process wouldn’t become prohibitively expensive. The only issue there, compared to a product like Revive’s glutamine, is that you’re adding a lot of powder to a glass of water or a smoothie. Revive’s more concentrated 10g formula is a little easier to work with and quite a bit easier to drink than Kaged at a 10g (double serving) amount.

If budget is your primary concern, you likely can’t do better for a product that costs only $0.25 per serving and boasts vegan ingredients, Informed-Sport certification, and third-party testing. Some other companies, like Transparent Labs and Revive, make their third-party testing results readily available on their websites. Kaged subjects its product to third-party testing but keeps those results to itself. (We prefer more transparency.)

Taste and mixability

As we alluded to earlier, a dose-for-dose comparison with Revive Glutamine reveals that Kaged doesn’t mix as well or taste as good as some of the competition. It’s fine for an unflavored option, and it only settles out a little bit into a glass of water. In a thicker drink like a protein shake, you’ll likely never know it was there.

One aspect of the preparation process we appreciated was the length of the Kaged scoop. Most glutamine supplements come with scoops to measure out doses, but these can sometimes be too short to reach the bottom of the container comfortably as it gets close to empty. The scoop that Kaged provides has an elongated handle that makes getting the last bits of glutamine and measuring them accurately easier than with many others.

Pricing and policies

Among the companies we recommend for glutamine, Kaged Glutamine’s price is the lowest per gram of glutamine. Each container has 500g — 100 5g servings of glutamine — for $24.99 ($0.25 per serving). If you subscribe, that cost comes down to $22.49 ($0.23 per serving), and you can choose a four- six- or eight-week delivery schedule.

Like the other companies we mention, Kaged requires you to hit a certain threshold before free shipping kicks in. Subscriptions ship for free, but Kaged’s requirement is $79 for one-time purchases, with standard shipping costing $6.99. However, that $79 makes it the second-lowest threshold, only beaten by Bulk Supplement’s $59 requirement. Every other company mentioned has a threshold of $100 or more.

Kaged is the only company here other than Onnit to offer an actual money-back guarantee on its products. Kaged’s satisfaction guarantee previously had some caveats we weren’t fans of, but the company’s policy has been updated in the past few months to be much more consumer-friendly. Kaged’s 30-day policy is now a generous 60-day one (but Onnit’s 90-day policy still beats it), and the company will accept returns of products from direct purchases and from authorized sellers in the United States.

There are no longer products excluded from this guarantee, and the company also appears to have removed its previous requirement that customers can’t use half or more of a product if they want to return it. Kaged only states that it “reserves the right to verify information, require a valid proof of purchase, and to deny Guarantee requests in its discretion in cases of suspected fraud or where Kaged concludes that the purchaser has abused the Guarantee.”

Onnit L-Glutamine Amino Acid

Best money-back guarantee


  • Affordably priced
  • Informed Sport-certified
  • 90-day “Keep-It” money-back guarantee
  • Generous discounts for first responders, military, medical workers, and teachers
  • Subscribe and save 15%


  • Unflavored option only
  • You must spend $100 to earn free shipping

Onnit offers a wide array of health and wellness supplements, many of which focus on cognitive and exercise performance. The company’s central product is Alpha Brain, a nootropic designed to support memory, cognition, and learning.

Onnit’s L-Glutamine Amino Acid is listed among the company’s gut health supplements and contains L-glutamine with no other active ingredients, ensuring you get a pure dose of this potent amino acid. Onnit’s supplement is also Informed-Sport certified, meaning that it’s free from banned substances and not a problem for competitive athletes to use.

Taste and mixability

Onnit performs on par with most unflavored glutamine supplements, dissolving well into water and not tasting like much. Like most other unflavored options offering 5g serving sizes, Onnit’s mix couldn’t quite compete with Revive’s in terms of mix or taste when the doses were equal.


A 60-serving tub of Onnit’s glutamine supplement costs $21.99 to purchase once. You can opt for a subscription to save 15% ($18.69/tub).

Your order will auto-ship every 7-90 days, depending on your preference. Onnit offers free shipping on orders over $100, which is $1 more than Transparent Labs, but $50 less than if you buy directly from Revive. Only Kaged and Bulk Supplements have superior shipping policies.

Onnit’s Keep-It guarantee is one of the main reasons we feel people would gravitate toward this company over another for glutamine. Onnit doesn’t exactly have the best price, but its guarantee covers all first-time orders. This guarantee gives you 90 days (about three months) to initiate a potential refund if you’re unsatisfied with the product.

However, you’ll need to try out the product (or at least hold onto it) for at least 30 days before initiating a refund. Some Onnit products only require a 2-week trial period, but its glutamine falls under the 30-day category. And, similar to Kaged’s old policy, Onnit has a list of products that are eligible for the Keep-It guarantee. Fortunately, glutamine is on that list, but we recommend checking that list if you plan on purchasing other products with your glutamine. But the length of the policy and the ability to keep the product still make Onnit our choice for the best money-back guarantee.

Bulk Supplements N-Acetyl L-Glutamine Powder


  • Pay as little as $0.03 per gram of glutamine
  • Choose from six product sizes — up to 25kg (55lb) of powder
  • Free shipping on orders over $59 in the contiguous U.S.
  • Gluten-free formula
  • 30-day return policy
  • Subscribe and save 10% or use code INNERBODY5 to save 5% without subscribing


  • Specific form of glutamine may be less well absorbed
  • Subscribers don’t automatically get free shipping
  • Bags don’t come with scoops (you have to measure with a scale)

Bulk Supplements N-Acetyl L-Glutamine Powder could be a better budget pick than what Kaged offers if you’re willing to spend more up-front. But that minimum investment, which gets you more than 2lb of glutamine, is likely more than most people need when they’re first starting out. It’s possible that you might end up taking an especially high dose with sufficient regularity (multiple times daily) that Bulk Supplements becomes your go-to pick for savings. We just feel that the average person would be better off starting with the kind of savings Kaged offers with a more modest investment.

One sticking point for Bulk Supplements is that it uses an acetylated form of glutamine (N-acetyl L-glutamine, sometimes called NAG). NAG has a better shelf-life than L-glutamine and is more soluble in water, but some research suggests that it doesn’t absorb into the bloodstream as well as L-glutamine, so dosing may not be equivalent.

Bulk Supplements lists its serving size as 750mg (or “about 1/3 tsp”), which is significantly lower than other companies and a lot lower than what we often see used in research. You can easily get a higher dose than this, but if you’re calculating your budget based on servings, this could throw you off a bit. The powder does not contain added sugar, soy, dairy, yeast, gluten, or other additives.

Taste and mixability

As you might have guessed from the brief mention of NAG above, Bulk Supplements N-Acetyl L-Glutamine mixes very well in water. The taste is on par with L-glutamine delivered by other unflavored options from Revive, Kaged, and Onnit. And thanks to its high degree of mixability, you can readily add it to just about any beverage you like to improve the taste.


A one-time purchase of a 100g bag of powder (the smallest option) costs $14.96. You can also opt for a subscription purchase and save 10% (or take 5% off without subscribing using code INNERBODY5).

Here’s a look at each bulk level and price for one-time and subscription purchases:

One-time purchaseSubscription price
100g (3.5oz)$14.96$13.46
250g (8.8oz)$21.96$19.76
500g (1.1lbs)$31.96$28.76
1kg (2.2lbs)$50.96$45.86
5kg (11lbs)$229.96$206.96
25kg (55lbs)$818.75$736.88

If you choose to join the subscription program, your order will auto-ship every 1-6 months based on what you choose. Bulk Supplements provides free shipping on orders over $59 placed in the contiguous U.S. and covers orders with a 30-day return policy. Unopened products are eligible for a full refund, but opened products pose some more risk to your investment. Bulk Supplements will only refund the price of its smallest available unit for any opened product. So, if you spent $51 on a 1kg bag of its glutamine, you’d only get $14.96 back as a refund (the cost of the smallest available unit).

Glutamine supplement FAQ

Alternatives to glutamine supplements

Potential alternatives to glutamine supplements may be a better path forward, depending on your particular health goals. The important thing is to identify what those goals are or possibly consult with your physician to decide which route is best for you, given any potential conditions or contraindications for current medications.

Let’s take a quick look at some alternatives to glutamine supplements and discuss their potential uses. None of these are mutually exclusive to glutamine, so you could also take them alongside a glutamine supplement:

Amino acids

There’s a good chance you’re getting enough glutamine in your diet to maintain good health if you’re already eating relatively healthy. But if you’re looking for a boost in essential amino acids, these supplements may be a superior option to glutamine alone. Some may even contain conditionally essential amino acids like glutamine. We have a guide to the best amino acid supplements with more information.


If you’re looking to use glutamine as a means to address your gut health, taking a probiotic might be equally effective. You may also want to get your microbiome tested and pay a visit to a gastroenterologist.

Protein powders

For those seeking a way to build more muscle, glutamine and BCAAs have a role to play, but if you have a hard time putting on any kind of weight — fat or muscle — you’ll need more calories in conjunction with protein. Protein powders and mass gainers are great for this, and many contain large amounts of all 20 amino acids, including glutamine. You can learn more about adding muscle in our guide to the best muscle-building stacks.



Innerbody uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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