L-Glutamine Supplement Benefits, Side Effects & Best Powder

After hearing a lot of amazing things about L-Glutamine, I decided to start using it at some point a few years ago. The supposed benefits of this supplement seemed pretty impressive while the potential side effects seemed non-existent.

Well now, years later, I’m finally ready to do a complete and honest review of it and let you know about the REAL benefits, the REAL side effects, and the overall truth about what an l-glutamine supplement does and does not actually do.

Let’s begin…

What Is L-Glutamine?

First let’s start with what it isn’t. No matter what the idiot in the supplement store tells you (or the company itself claims), l-glutamine is not a muscle builder or a fat burner. It won’t make you bigger or stronger or burn fat or do any of those types of things in any way whatsoever.

Instead, l-glutamine is the most abundant inessential amino acid in the human body and makes up the majority of the amino acids in skeletal muscle. Despite being involved in many crucial roles in our daily health and function, it’s considered “inessential” because the body is capable of producing it on its own.

However, there are situations when l-glutamine can become essential… the most notable of which is when intense activity (like weight training, cardio, etc.) is being performed on a regular basis. And this of course is why it became a popular supplement among people who exercise regularly.

What Are The Legitimate Benefits?

First let’s start with the not-so-real benefits that have mostly been proven to not actually exist.

The Fake Benefits

I’m pretty sure the original reason I started taking an l-glutamine supplement back in the day was because of its supposed anti-catabolic effects. Catabolism refers to the breaking down of your muscle tissue, which is something that you don’t want to happen.

Basically, the thought was that since people who were trying to lose fat (and were therefore eating less calories, doing more cardio, etc.) were at a higher risk of muscle loss (which is true), taking an l-glutamine supplement would help maintain muscle thanks to its amazing anti-catabolic muscle preserving effects and benefits.

Sounds pretty awesome, right? I thought so too. Unfortunately, it’s mostly bullshit. The studies people incorrectly got this idea from were hardly relevant to healthy and active adults. So no, these types of benefits don’t actually exist.

Now, while I was busy taking it because I thought it was helping me maintain muscle while losing fat, there were apparently a TON of people taking it because they thought it built muscle. (And yes, a ton of people still take it for this very reason).

Of course, the idea that an l-glutamine supplement builds muscle is complete and utter bullshit. I can only assume this idea came as a result of the fact that l-glutamine is the most abundant amino acid in muscle, so if you took more of it, it would somehow lead to more/bigger/better muscle? Ha, funny stuff.

And let’s not forget the supplement companies and fitness magazines. They are probably the most to blame for this and countless other false benefits of supplements. I’ve seen them claim a multivitamin can build muscle, so I’m sure all kinds of amazing effects were claimed about this one.

But no… NONE of it is true.

The Real Benefits

Now so far it seems like an l-glutamine supplement is completely useless, right? Well, while it’s no where near as amazing as some people used to (and still do) think it is, it still most definitely has some useful benefits and effects on the human body.

Specifically, it…

  • Supports workout and muscle recovery.
  • Enhances immune function.
  • Improves intestinal health.

These are the benefits that are actually legit and proven in both science and the real world (unlike the nonsense I mentioned a minute ago), and the first two benefits on that list are the reason I still take it and would recommend anyone else take it as well.

People taking an l-glutamine supplement often report reduced muscle soreness and enhanced workout recovery. A lot of people also swear by it as a sickness-preventer, basically helping them avoid catching colds and that sort of thing.

What do I think? Well, I mostly agree.

In all the years I’ve been taking it, I have purposely stopped for certain periods of time just to see if I notice any difference in terms of effects or benefits. And honestly, I DO feel like it helps in some way with workout/muscle recovery as well as either reducing the amount of soreness I experience, or just helping that soreness go away sooner.

And regarding improved immune function, I have a feeling it HAS helped me there as well.

It’s harder to say for sure as an overall healthy diet will enhance immune function, but if I had to guess, I’d say yeah… it probably does help. After all, intense exercise actually hinders immune function, so a supplement that helps it would make sense.

So, for both of these reasons, I continue taking (and recommending) an l-glutamine supplement.

Are There Any Side Effects?

Nope, as long as you’re not taking INSANE amounts of it, there are no real side effects. It’s pretty much exactly as safe as any other basic and obviously safe supplement that contains a nutrient you can get naturally from food. You know, like protein powder.

Speaking of which, something a lot of people don’t realize when they’re searching for l-glutamine side effects and benefits is that they’re usually already taking it. How? Well, are you taking any sort of protein supplement? You know, like whey protein powder?

If so, check the ingredients. Nearly every whey protein powder (and protein supplement in general) contains some added amount of l-glutamine. I’m surprised how many people don’t see this, as most protein powder’s go out of their way to mention it on the label as some kind of bonus selling point.

Of course, it takes more than the couple of grams of it they include to get the recovery and immune function related benefits it can provide, but it’s worth mentioning anyway.

How Much Should I Take, And When Should I Take It?

Well, in addition to the couple of grams you may be getting from protein powder and your diet in general, an additional 5-15 grams is probably the amount needed to get the various benefits it provides.

I personally take 10 grams on days I work out, and 5 grams on the days I don’t.

As for when to take it, an l-glutamine supplement is likely most beneficial when taken before and/or after your workout (which is why I always include 5 grams in my post workout meal). On the days you don’t work out, first thing in the morning and maybe right before bed are probably good choices.

Also, it can be mixed just fine with water or any other liquid you want. You can throw it in with your protein shake or creatine or whatever else you might be taking. It’s perfectly fine.

What Brand Is The Best?

As with most supplements, it’s mostly a matter of form, quality and price.

L-glutamine supplements come in both powder and capsule form. However, you definitely want powder. Capsules cost more and you’ll need to take a few to get the same amount 1 spoonful of the powder would provide.

And don’t get any kind of fancy flavored version either. It’s virtually tasteless and odorless, so anything other than plain powder is a waste of money.

As for which brand is best, anything meeting these guidelines should be fine.

But if you want a recommendation, I personally use and highly recommend Optimum Nutrition Glutamine.

Summing It Up

So, will taking an l-glutamine supplement magically make you build muscle, lose fat, or maintain muscle while losing fat? No, these benefits are bullshit.

But, will it improve workout recovery, reduce muscle soreness, and enhance immune function… all without any side effects? Yeah, most likely.

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