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The Best Glutamine Supplement – UK Reviews

If you’re a serious bodybuilder, you’re going to hit a plateau at some point in your lifting career. In the beginning, the gains come easy even if you’re slacking on your nutrition and supplements. But as you reach your genetic potential, you’ll have to work progressively harder to make smaller and smaller gains.

Once you have your basic protein and supplement regime in place, you’re going to have to look for ways to increase your recovery and overall work capacity.

Tub of Glutamine powder

Glutamine is an interesting supplement because its benefits aren’t as direct as supplements like whey or creatine. It plays a supportive role to help keep your body healthy despite the consent stress of heavy lifting.

Keep reading to find out specifically how taking a glutamine supplement can increase the quality of your training sessions. We’ll also review some of the best supplements on the market to help you find the one that best fits your need. Let’s get started.

What is Glutamine?

Glutamine is the most common of the 21 amino acids that make up every protein in your body. It’s considered a conditionally essential amino acid. Although your body can usually create it, at certain times your body’s requirement is higher than the amount it can produce.

When you’re short on glutamine, your body looks for tissues it can break down to get more of it. Your body will start by dismantling unessential tissue before breaking down the structures of your organs. Unfortunately, your body doesn’t consider the muscles you’ve been sculpting in the gym for months essential.

The primary role of glutamine in your supplement stack is to preserve muscle tissue during periods of increased need. We’ll explain specifically when your body needs more glutamine in the benefits section below.

Glutamine comes in two forms: L-glutamine and D-glutamine.

As far as scientists know, D-glutamine doesn’t play a role in your health. L-glutamine is the form your body uses to create protein. It’s worth noting that many supplements refer to L-glutamine as simply glutamine.

Types of L-Glutamine

As we mentioned, D-Glutamine doesn’t seem to play a role in human health, and you’ll never find a D-Glutamine supplement.

You’ll find L-glutamine in several different forms including powders, capsules, and tablets.

L-Glutamine also comes in the form of glutamine peptides. Glutamine peptides are strands of glutamine bound to other amino acids to make them more stable. However, free glutamine is the form most often used in research and is thought to be more bioavailable.

Glutamine Benefits

As we touched on, your body can usually produce L-glutamine, but at times, your body’s need for this amino acid is higher than the amount it can create. Your body may rely on dietary glutamine during periods of stress such as during an intense workout, when fighting illness or infection, or after periods of physical trauma.

Glutamine May Increase Immune Function

Glutamine is essential for the formation of white blood cells and other immune cells. If you’re low on glutamine, your body’s ability to defend itself from bacteria and viruses becomes compromised.

If your primary goal is to increase the size of your muscles, supporting your immune system may not seem like your top priority. However, more sick days means more days off from training.

For the average lifter, a few extra rest days won’t derail your progress entirely. However, if you’re a competitive bodybuilder, the last thing you want is a flu disrupting a training block, especially if it’s close to your competition prep.

Much of the research on glutamine at this time has been performed on animals. However, there have been a few studies performed specifically on athletes.

In a double-blind study published in 2015, researchers gave a group of 24 athletes 10 g of glutamine daily for six weeks. They found that athletes who took glutamine had increased levels of several immunity markers.

Glutamine May Decrease Muscle Soreness

If you want to experience muscle growth, you have to stress them by lifting heavy and lifting often. Glutamine may decrease muscle soreness after exercise, which can help get you back in the gym faster after a particularly hard session.

A study published in Canada in 2015 looked at the effect of taking glutamine on muscle soreness 72 hours after a workout.

They found that participants who took glutamine had significantly lower reported amounts of muscle soreness and faster muscle recovery times (measured by single-legged knee extension force). Interesting enough, they found that men responded more than women (although the sample size was relatively small).

Glutamine Supplementation May Help Digestion

If you have a sensitive stomach, you may benefit from adding glutamine to your supplement stack. Research is still fairly new on the effect of glutamine on your digestive health, but early results look promising.

The cells in your intestines use glutamine as a source of energy. They also need glutamine to grow and develop. It’s thought that taking a glutamine supplement can help with conditions like leaky gut and irritable bowel syndrome (IBS).

In one study published in 2019, researchers gave participants with IBS 5 g of glutamine per day. They found that participants who took glutamine had reduced IBS symptoms with no side-effects reported.

How Much Glutamine Do You Need to Take?

You already get roughly 3-6 g of glutamine in your diet without thinking about it. Glutamine is found in all your protein-dense foods such as red meat, eggs, fish, and whey powder.

Most of the research on glutamine uses a daily serving around 5 g per day. However, in the study that found that taking glutamine may boost the immune system of athletes, the researchers used 10 g per day.

We recommend that you stick to a 5 g serving per day because it’s isn’t clear at this time if taking a higher dose leads to more benefits. Containers of glutamine come in sizes up to about 1 kg. If you take 5 g per day, that gives you more than a six-month supply.

Are There Any Side Effects?

If you’re like most lifters, you’re probably already consuming a high-protein and high glutamine diet. Taking glutamine is generally considered safe and the only people who seem to react to it are people with an allergy. If you’re allergic, the most likely side effects are stomach pain, bloating, and nausea.

Even extremely high doses of glutamine appear to be safe. One study looked at the effect of 0.9 g/kg of body weight (90 g per day for a 100 kg person) and the researchers didn’t report any side-effects.

When is the Best Time to Take Glutamine?

The best time to take glutamine is after your workout to help preserve muscle tissue. If you have a particularly long workout, over two hours, you may want to take it during your workout as well.

It’s thought that glutamine supplementation also causes a small spike in your insulin levels. As you may already know, insulin helps shuttle carbohydrates and protein into your muscles after your workout.

If you’re recovering from an injury or illness, you should definitely consider adding glutamine to your supplement stack. You may even want to double up your daily dose to 10 per day.

A Detailed Look at the Best Glutamine Supplements

There’s no shortage of glutamine supplements on the UK market. We’ve broken down some of the more common types below to help you find one that best fits your needs.

Keep these three points in mind when looking for a supplement:

  • The general dose of glutamine per day is 5 g. An easy way to determine how many servings are in a container is to divide the total weight by five.
  • L-glutamine is the preferred form of glutamine used in research and seems to be more effective than glutamine peptides.
  • If you plan on mixing your glutamine with other supplements, you might want to go with an unflavoured supplement.

Editor’s Choice: BULK Pure Glutamine Powder

Bulk has a reputation for providing high-quality supplements at great prices. Their L-glutamine powder is one of the cheapest on the market, and you can order it in bags up to 1 kg to get the best per scoop price.

As we mentioned before, L-glutamine is conditionally essential, and your need rises during injury or illness. If you buy a Bulk 1 kg container, you get more than a 6-month supply to make sure that you don’t run out when you need it the most.

Things We Like
  • Flavoured and unflavoured options
  • Great per serving price
  • 1kg bag option
Things we don’t like
  • Not clear if it’s vegetarian-friendly
  • A few customers have reported the scoop missing


Bulk is one of the leading supplement brands on the market. Their L-glutamine supplement comes at an excellent per serving price. If you want to get the best price, you can buy the 1 kg bag. However, if you want to see how your body reacts before committing to a full kilogram, you can try the 100 g bag.

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Grenade Essentials Glutamine

Grenade Essentials Glutamine is a 100% L-glutamine supplement. It doesn’t contain any artificial sweeteners or fluff ingredients. It only comes in one flavour, unflavoured, so it makes a perfect choice for anybody looking to stack it with other supplements.

This L-glutamine supplement can help you support your immune system even when you’re going through a heavy training block. If you’re on a vegan or vegetarian diet, you can take this supplement without worry.

Things We Like
  • Large container size (1.8kg)
  • Good flavour selection
  • Contains a mix of whey isolate and micellar casein
Things we don’t like
  • No flavoured options
  • No 1kg option


Grenade Essentials Glutamine makes a great option if you like to stack your supplements because it’s unflavoured. You can easily mix it with other powders without changing the taste. However, because there are no favoured options, you may want to go with a different brand if you plan on taking it by itself and if taste is important to you.

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Iron Labs Nutrition Vegetarian Glutamine

Iron Labs Nutrition Vegetarian Glutamine comes in tablets, unlike most glutamine supplements that come in powdered form. Each serving provides you with 3 g of glutamine to help support your immune system and muscles during hard blocks of training.

If you prefer tablets over powder, this L-glutamine makes a great choice. You can easily throw it in your bag and take it at the gym.

Things We Like
  • Tablets are convenient
  • Vegetarian-friendly
  • Made in the UK
Things we don’t like
  • Relatively expensive per serving
  • Only 3g of glutamine per serving
  • Have to take 6 tablets per serving


If you prefer tablets over powder, you might like this glutamine supplement. It’s a little more expensive per serving than many of the powders we’ve looked at because there are only 40 servings per container. However, if you’re looking for something no-hassle to throw in your bag, this is a good option.

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The Protein Works Glutamine Supplement Powder

The Protein Works is another well-known supplement brand that offers a great price on their glutamine supplement. You can order this supplement in one of three sizes (250 g, 500 g, and 1 kg). The larger the container you order, the better the price per scoop.

You can enjoy this product no matter whether you want something flavoured to take by itself or something unflavoured to mix with your other supplements.

Things We Like
  • Flavoured and unflavoured options
  • Three size options
  • Vegetarian-friendly
Things we don’t like
  • Around market average price
  • Only one flavoured option


It’s hard to find much wrong with this glutamine supplement. Price-wise, it’s around the market average, but it provides you with a high-quality product form a brand with a good reputation. This powder makes a great choice no matter whether you’re looking for something flavoured or unflavoured.

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Reflex Nutrition L-Glutamine

Reflex Nutrition’s L-Glutamine supplement contains 5g of unflavoured glutamine per serving. Like many of the supplements we’ve reviewed, it comes unflavoured so you can easily mix it with other supplements without changing the flavour.

If you’re looking for an L-glutamine supplement made in the UK without any filler ingredients, there’s a good chance you’ll like this supplement.

Things We Like
  • No artificial sweeteners
  • Made in the UK
  • About average price
Things we don’t like
  • Only one container option
  • Not clear where the glutamine is sourced from


Overall, this glutamine supplement is a fairly basic L-glutamine supplement that has an average price. It comes in one container size (500 g) and one flavour (unflavoured). The biggest selling point of this supplement is that it’s made in the UK.

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MyProtein Unflavoured L Glutamine

MyProtein’s L-Glutamine is an unflavoured supplement that provides a solid 5g of L-glutamine per serving at a great price. If you’re looking for a simple glutamine supplement that will help boost your immune system, this makes a great option.

MyProtein L-glutamine offers one of the best prices we’ve seen to help you keep your immune system strong full without hurting your wallet.

Things We Like
  • Great price
  • No artificial sweeteners
  • 5g of L-glutamine per scoop
Things we don’t like
  • Only one flavour option (unflavoured)
  • Some customers report a funny aftertaste


Overall, this glutamine supplement offers great value at a solid price. If you’re looking for an unflavoured powdered glutamine supplement, this makes a great option. It’s also a great choice if you have any dietary restrictions because it’s vegan and vegetarian-friendly being dairy, animal product, and gluten-free.

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Optimum Nutrition ON Glutamine Powder

Optimum Nutrition is one of the more well-known brands in the supplement world. Their unflavoured L-glutamine powder comes in a 1050 g container size.

They have a good reputation for delivering high-quality supplements, and this supplement offers you 205 servings of glutamine at a solid price. If you’re looking for a L-glutamine supplement from a well-known brand, this might be the product for you.

Things We Like
  • Well-known brand
  • Large container size
  • Slightly better than average price
Things we don’t like
  • Not 100% L-Glutamine
  • Filler ingredients
  • Not clear if it’s vegetarian-friendly


Optimum Nutrition’s glutamine supplement provides you with a solid 5g of glutamine per serving. It also comes in a relatively large container size that should last well over 6 months if you take it once per day.

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Bodybuilding Warehouse Pure L-Glutamine Powder

Bodybuilding Warehouse’s L-glutamine supply is designed to help support your body through hard periods of training. As we’ve mentioned, when you’re in a particularly intense block of training, your body’s immune system can be compromised. This supplement helps prevent that.

If you’re looking for a cheap glutamine supplement that can support your training, this is a great option.

Things We Like
  • Three container size options
  • No artificial sweeteners
  • Excellent price
Things we don’t like
  • Scoop is bigger than 5 g
  • Only one flavour option


This glutamine supply provides you with excellent value per scoop. If you want the best price, go with the 1 kg container. The only thing that’s a little annoying about this supplement is the standard serving size is 2/3rds of a scoop, which means it’s a little harder to measure. If that doesn’t bother you, it makes a great option.

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USN Glutamine Pure Micronised Powder

USN’s Glutamine powder is micronised to increase its mixability. This makes it a great choice if you hate the gritty feeling that some supplements leave in your mouth.

It’s a little more expensive than most glutamine supplements. But if you don’t mind paying a little extra for a smoother product, this supplement can make your shakes a little easier to drink.

Things We Like
  • Large container size
  • Micronised for improved mixability
  • No artificial sweeteners
Things we don’t like
  • No flavour options
  • A little expensive


If you’re looking for a supplement that mixes very well in water, this might be a great choice for you. It’s a little more expensive than the average glutamine supplement, but if you prioritize texture, you may still prefer this supplement.

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Glutamine helps support your muscles and immune system when you’re training hard. The last thing you want to do when you’re in an intense block of training is to have to deload because of illness. The further along you get in your lifting career, the more important it is to minimize the number of days of training you miss.

There are plenty of great L-glutamine supplements available, but there are a few that jump out at us.

If you’re looking for a great per serving price, it’s difficult to beat Bulk Powders’ L-glutamine supplement. It comes in bags up to 1 kg so you can buy more than a six-month supply at a time.

Most of the supplements we looked at are unflavoured. If you want a flavoured option, you may like The Protein Works glutamine supplement. It comes in both unflavoured and orange-burst. You can also buy it containers up to 1 kg to get the best price per scoop.

If you prefer taking tablets over a powder, you may want to try Iron Labs Nutrition’s glutamine supplement. Instead of taking a scoop of powder like with most glutamine products, you can take six tablets daily.

Photo of author

Jason Barnham

Jason started lifting weights back in 1990 which sparked his interest in Nutrition. He went back to college in 1993 then started at the University of Surrey in 1994, graduating in Nutrition and Dietetics in 1998.

Having worked in both the NHS and running his own dietetic clinic, he has now settled into the web publishing world.

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