Best Glutamine Supplement

Some of the most prevalent health issues today, from obesity and diabetes to GI distress and low immunity, may be related to specific amino acid deficiencies. 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.1

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 investigation.

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:

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 160 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.

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 consider effectiveness and safety as top criteria. While glutamine’s safety and efficacy are largely based on dosage, there are some other factors that may make one choice safer than another.

It’s also 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.

Effectiveness

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.2 Substantial research also 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 many servings, either; even if we compare relatively equal scoop sizes, a dose of Revive contains double the amount of glutamine (10g as opposed to 5g). What’s more, Revive produces a mixture that’s easier to both make and 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. It’s also at the top of our guide to BCAAs for women and is one of our top recommendations for amino acid supplements in general.

Safety

Winner: Transparent Labs

With 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) doesn’t regulate supplements the same way as food and prescription drugs, you must 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. Another thing the company does to demonstrate its commitment to safety and transparency is to list the exact quantities of the supplement’s “other ingredients,” right down to the stabilizers used to extend shelf life. Usually, with nutritional supplements, you only see doses for active ingredients (and if a company uses proprietary blends, you won’t even get that information), so Transparent Labs’ approach to labeling is rather unique.

Cost

Winner: Kaged

Comparing one glutamine supplement’s pricing to another’s requires a little bit of math. That’s because many companies deliver their supplements with varying numbers of servings. 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 only two companies on our list to offer additional discounts for military personnel, teachers, students, and first responders (the other being Revive). Once you verify your status, you’ll be able to get 20% off any Kaged order up to once per day. Revive’s discount is “up to 20%,” with no more specificity as to what criteria qualify you for the full 20% discount and what doesn’t.

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

Kaged edged out its competitors with superior communication (it was the only company to include a final delivery notification among its emails), faster shipping speed (just four days), and the best money-back guarantee among the options in our guide (60 days).

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

The sticker prices for most glutamine supplements appear 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:

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.

Glutamine is an amino acid that aids in synthesizing proteins. Apart from building muscle, proteins help with other things that keep us alive, like keeping the organs functioning and fighting off infection.3 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 from external sources 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’s 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.4 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):24

• Building muscle
• Reducing exercise recovery time and improving feelings of well-being in athletes25
• Supporting immunity
• Enhancing intestinal health (and potentially helping symptoms of IBS and ulcerative colitis)26 27
• Reducing oral inflammation from cancer therapy16
• Inhibiting colon cancer cells when combined with thiosemicarbazide in silver nanoparticles28
• Promoting weight loss

While scientific research has shown glutamine’s importance to immunity and intestinal health, more research must be done to affirm its role in muscle building and weight management.4 Nonetheless, it’s a popular pre- and post-workout supplement ingredient.

Most people can obtain glutamine from a balanced diet, particularly from high-protein foods like:

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

But if you have certain leaky gut symptoms or you want to take your workouts 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.5 Essentially, the amount of glutamine you take daily depends on your desired outcome, the product’s serving suggestions, and your doctor’s recommendations.

Glutamine supplements work by boosting your body’s glutamine levels and helping it synthesize proteins more effectively, which can accelerate muscle and tissue repair and fight illness and infections.6 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.6

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. A wealth of research has been conducted on this potential link. 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.7
• 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.8
• 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.9
• Several animal studies show that glutamine boosts the immunity of animals with viral infections.10
• 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.29

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,11 while others found that glutamine can help with IBS,26 ulcerative colitis,27 and intestinal permeability (the clinical term for leaky gut).12 And a separate study on rodents found that glutamine reduced intestinal permeability after a bile duct blockage.13

Muscles and exercise

Given its role in synthesizing protein, as well as its frequent inclusion in pre- and post-workout supplements, we might easily assume that glutamine facilitates muscle building. But clinical testing doesn't support this assumption. For example, in one trial, participants took glutamine supplements for six weeks while weight training and showed no significant muscle gain or performance changes.5 Similar studies have shown comparable results.

On the other hand, some clinical trials have shown that glutamine supplementation can potentially lead to improved exercise recovery. One trial showed that male participants experienced improved muscle recovery and soreness after supplementing with glutamine and performing knee extensions.14

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. The researchers ultimately suggested that L-glutamine could be beneficial for “the sports performance and recovery of athletes.”25

Weight loss

As with muscle building, glutamine’s effect on weight loss is still inconclusive and requires more testing, but 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.15

Glutamine supplements may be a good choice if you’re interested in boosting your immunity or intestinal health. They 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. It 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.16 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’re interested in building muscle, speeding up exercise recovery, or losing weight. Even though clinical research about glutamine’s impacts is still inconclusive, user testimonials of many glutamine-based products indicate they can be effective as pre- and post-workout supplements.

Who should avoid glutamine supplements?

While glutamine may have several uses, generally healthy individuals without GI symptoms or issues building muscle, losing weight, or recovering from an illness or injury might not need to try a glutamine supplement.

There are also situations where glutamine might not be your best course of action, even if you’re experiencing symptoms that glutamine has resolved in some studies. This is especially true with GI symptoms. The GI system is so complex that you might have far better results trying a probiotic supplement, digestive enzymes, or simply a change in diet.

Your doctor can give you more guidance about your specific needs with the help of some diagnostic testing, and we have an alternatives section below that provides more detail, as well.

Glutamine supplements are generally safe to take for most healthy adults who aren’t pregnant or breastfeeding. Studies have illustrated glutamine’s tolerability in dose 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, discontinue use and seek immediate medical attention.

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 use.

The jury is still out concerning the safety of taking glutamine supplements long-term.19 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 arise if you plan to take glutamine for longer than a few weeks.

Some health conditions may be exacerbated by glutamine supplementation. If you’re 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

A glutamine 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,28 other clinical research shows that it may increase tumor production.17 If you’re living with cancer (or are at risk for cancer), talk to your doctor about whether glutamine is safe for you. In fact, it’s important to talk to a doctor before beginning any new supplement, as qualified healthcare practitioners have the most up-to-date knowledge about potential contraindications.

Although glutamine supplementation has been used to care for infants and children, consult with a pediatrician before giving glutamine to anyone under age 18.18

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

Best overall and best high-dose

While most companies seem content to provide a 5g serving size for their glutamine supplements, Revive doubles that dose without doubling the powder volume. 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. That's not a bad way to get to 10g, but double-dosing will likely result in more clouding and a more intense taste. Revive's higher strength in the same scoop volume as its competitors allows for a better user experience.

Like many glutamine supplements, Revive Glutamine contains nothing but L-glutamine.

Taste and mixability

BCAA and EAA supplements typically taste abhorrent, but we find that Revive Glutamine has a very mild taste you can obscure by adding a splash of fresh lemon juice or mixing it into an electrolyte-rich beverage like Gatorade. Revive also mixes very well into plain water. It turns the water a milky white color but doesn't settle out much once it's mixed in. Our testers found they could dissolve it almost entirely by swirling the glass before taking it the rest of the way with a spoon.

Pricing

We often recommend purchasing products directly from supplement companies to take advantage of unique perks like subscription deals, but Revive doesn’t offer a subscription deal — both one-time purchases and subscriptions cost the exact same. It’s one case where we’d say buying from Amazon could be advantageous for you. In the chart below, we break down the pricing from both Revive and Amazon.

Even if you only want one container, you can still subscribe on Amazon and cancel it right after the product ships. Of course, the pricing on Amazon may not remain favorable.

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. Meanwhile, shipping from Amazon is free on orders over $35, so subscribing quarterly and buying three containers at a time would get you over the threshold.

Revive only gives you 15 days to return a product, and it has to be unopened. 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 Kaged 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. It’s worth noting that Amazon lists Revive Glutamine as non-returnable, too, so going that route for more convenient returns isn’t an option.

Best pre-workout

Transparent Labs BCAA Glutamine Powder is our top pre-workout because it boosts your muscle-building potential by combining the power of glutamine with leucine, isoleucine, and valine — BCAAs that have the potential to 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.

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’s some evidence that amino acid supplementation can negatively impact the kidneys and even lead to the development of kidney stones,20 but coconut water powder has shown potential to work against this.21 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.22

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

Transparent Labs BCAA Glutamine contains BCAAs, so an unflavored version wouldn’t be very pleasant to drink. Luckily, 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 with 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.

Pricing

One tub of Transparent Labs BCAA Glutamine powder (a 30-day supply) costs $39.99. 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:

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 store credit or a product exchange.

Best budget pick and best money-back guarantee

Often, when we set out to review supplements, we find that Bulk Supplements (a little further down our list) 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. Truly, 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.

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 a double serving of Kaged.

As we mentioned, Kaged does subject its product to third-party testing. Unfortunately, it keeps the results to itself. Other companies, like Transparent Labs and Revive, make their third-party testing results readily available on their websites, and we’d prefer similar transparency from Kaged.

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. But 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 for measuring out doses. The scoops that come with most glutamine supplements are sometimes too short to comfortably reach the bottom of the container as it gets close to empty. The scoop that Kaged provides has an elongated handle that makes it easier not only to measure the powder accurately but also to get the last bits of glutamine in the jar.

Pricing and policies

Among the companies we recommend for glutamine, Kaged offers the lowest price per gram. Each container has 500g — one hundred 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 one-time purchases have a standard shipping cost of $6.99 unless you meet a $79 minimum order. However, that $79 threshold is second only to Bulk Supplement’s $59 requirement.

Kaged is the only company here to offer an actual money-back guarantee on its products, as well. The company’s satisfaction guarantee previously had some caveats we weren’t fans of, but its policy has been updated in the past few months to be much more consumer-friendly. Its previous 30-day policy is now a generous 60-day one, and the company will accept returns of both direct purchases and those from authorized sellers in the United States.

No Kaged products are excluded from this updated guarantee, and the company also appears to have removed its previous requirement that customers can’t use half or more of a product they wish to return. 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.”

Bulk Supplements N-Acetyl L-Glutamine Powder could be a better budget pick than Kaged if you’re willing to spend more up front. But that’s more glutamine than most people will need, especially when starting out. Considering the fine print in Bulk Supplements’ return policy (which we’ll discuss below), that higher up-front cost also comes with added risk. 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.4

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 increase your dose, but if you’re calculating your budget based on servings, that could throw you off a bit.

The powder doesn’t 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 and Kaged. And thanks to its high degree of mixability, you can readily add it to just about any beverage you like; depending on the drink you choose, doing so may help improve the taste.

Pricing

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:

If you choose to join the subscription program, your order will auto-ship every 1-6 months depending on the interval 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 more risk to your investment. For any opened product, Bulk Supplements will only refund the price of its smallest available unit. So, if you spent $162 on a 5kg bag of its glutamine, you’d only get $14.96 back as a refund (the cost of the smallest available unit).

Depending on your particular health goals, a glutamine alternative may be a better path forward. The important thing is to identify what your goals are and 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 take them alongside a glutamine supplement: