L-Glutamine Pre-Workout – Is it Necessary Before a Workout?

In the world of fitness and bodybuilding, countless supplements vie for attention, each claiming to be the key to optimal performance. 

One such supplement or, better yet, an ingredient in pre-workouts is L-glutamine. 

So here’s the million-dollar question – is L-glutamine pre-workout really necessary, and does it offer tangible benefits?

Let’s delve into this topic and find out.

What is L-Glutamine?

L-Glutamine is the most abundant amino acid in the human body, playing a crucial role in numerous physiological processes.

Naturally found in foods like meat, dairy, and some vegetables, L-glutamine can also be consumed as a supplement to boost its levels in the body.

But why?

It acts as a building block for protein synthesis, supports immune function, and aids in gut health. [1]

Now, the first portion is where it gets interesting because when an average Joe hears those “muscle protein synthesis”, their mind jumps straight into “bigger muscles”.

However, as you’ll see soon enough, that’s not really the case.

Why Do Some People Recommend Taking L-Glutamine Pre-Workout?

Supporters of L-glutamine pre-workout supplementation argue that it can potentially enhance endurance and promote muscle recovery. 

And sure, there has been some research on the topic, and there may be a reason for someone to believe glutamine could be advantageous because intense exercise can cause a temporary drop in L-glutamine levels.

Therefore, supplementing with it before a workout may help maintain a stable supply, thus preventing muscle breakdown and promoting faster recovery.

In theory, that kind of makes sense.

However, from what we know so far, there’s almost no evidence supporting the theory that glutamine can help with either endurance or recovery.

There have been some semi-positive results when it comes to ammonia build-up during long cardio sessions, but that’s about it. [2]

There’s also talk about glutamine supporting the production of citrulline (which is true and would definitely boost NO production). [3]

But, as long as you get a potent enough dose of L-citrulline in your pre-workout, any additional glutamine shouldn’t have any significant effect on the potency of the product.

Will L-Glutamine Actually Have Any Benefits When Taken Before a Workout?

The benefits of L-glutamine pre-workout supplementation remain somewhat contested.

And that’s a nice way of putting it. 

While some studies (like the one with ammonia we mentioned) suggest it could be mildly beneficial, most of the other research has found no significant performance or endurance enhancements, or recovery benefits.

In other words, the effectiveness of L-glutamine as a pre-workout supplement is pretty much non-existent. 

For those undergoing prolonged workouts, like, for example, hours-long cycling sessions, it could potentially be helpful. 

However, the average gym-goer most likely will not experience any noticeable benefits.

When is the Best Time to Take an L-Glutamine Supplement?

There isn’t a one-size-fits-all answer to this question. Mostly because it doesn’t matter because it’s not really effective from what we know so far, but also because people just can’t seem to agree on this issue (wonder why that is?).

That said, some people prefer taking it pre-workout, while others find it more beneficial post-workout or even before bed to “support recovery”. Some even claim it’s best you take it 10-15 minutes before every meal.

Ultimately, we’d argue that the best time to take an L-glutamine supplement (at least for muscle-building or performance-enhancing purposes) is never.

What’s a Good Dosage of L-Glutamine?

L-glutamine dosages can range from 5 to 50 grams per day, depending on individual needs. For most people, a good dosage of L-glutamine is 5 to 10 grams, split into 2 or 3 smaller doses.

However, if we’re talking about a dose that would help you with your gains – there isn’t one.

We can’t say such-and-such is an optimal dose of L-glutamine, seeing how there’s no concrete or consistent evidence suggesting it’s actually beneficial for gym-goers.

Is Supplementing With L-Glutamine Really Worth It for Bodybuilding?

In our opinion, supplementing with L-glutamine isn’t really worth it for bodybuilding.

That said, this amino acid could do a thing or two about your gut health and immune system, so if that’s something that may be keeping you out of the gym – it could be worth it for you.

In the end, it’s crucial to weigh the potential benefits against the costs and consider your unique situation before deciding whether to incorporate L-glutamine into your supplement regimen.


Regardless of its several applications and prevalent role in the body, L-glutamine’s effectiveness in the gym remains unproven and it is safe to say that it is not necessary for the average gym-goer.

Sure, L-glutamine supplementation may offer some benefits for specific individuals, particularly those with gut or immune issues, but that’s about it.

All things considered, it’s really hard to make a case for L-glutamine and if prefer not to waste money – we suggest you look for something else.

What to Read Next

L-Glutamine vs. BCAA – What’s the Difference?
L-Glutamine vs. BCAA
Can I Take L-Glutamine Before Bed? – How it Affects Sleep
L-Glutamine Before Bed
Share This Post

Providing you with the resources to build your best life and physique.

Articles: 125

Leave a Reply

Your email address will not be published. Required fields are marked *