As fitness lovers, we’re always looking for new ways to increase the pump. It’s about boosting blood flow, maximizing reps and volume, and pushing through a training session harder than you ever have before.

For a lot of athletes and fitness enthusiasts, the pump is something they chase. It’s a sign that whatever supplement they’ve taken is working, and they’re about to have a workout of a lifetime—but it takes a careful combination of supplements to achieve it.

The thing about the pump is that it may look great from an aesthetic point of view—yeah, everyone is definitely noticing the biceps—but it’s also the secret ingredient needed to trigger muscle growth.

So, while getting swole can be great for the mirror and your confidence, it’s not all cosmetic. You need the pump to increase blood flow to your hard-working muscles and deliver nutrients required to fuel muscle contraction.

Better blood flow also means increased cell volume, which, along with the mechanical tension created from lifting weights, is also a big thing that gives the green light for muscle adaptation.

And what’s the best way to get that pump?

The ultimate performance blend: Glutathione + L-citrulline—and it’s what we’re diving into now.

What Is Glutathione?

You’ve probably heard endless amounts of information on antioxidants. They’re needed to protect cells against oxidative stress and free radicals generated as a natural byproduct of metabolism, environmental exposures, and everything else under the sun.

But if there’s one antioxidant we want to rave about, it’s glutathione (GSH)—also called the “master antioxidant” for a good reason. It’s one of the most important hydrophilic antioxidants in the human body that protects cells against exogenous and endogenous toxins, including reactive oxygen (ROS or free radicals) and nitrogen (RNS) species 1.

While free radicals are generated through several things, including normal metabolic processes, strenuous physical activity also induces oxidative stress, whereby the production of free radicals can exceed the capabilities of the antioxidant system to combat them 2.

Research shows that even 30 minutes of sub-maximal activity is enough to increase oxidative stress and free radical formation, making boosting antioxidant defenses even more critical.

What Is L-Citrulline?

L-citrulline, on the other hand, is a non-protein amino acid native to one of the sweetest and juiciest fruits around—watermelon.

It can be synthesized in the body and plays an important role in the urea cycle in the liver and kidneys, but interestingly is rarely found in foods besides watermelon, which is the primary reason it’s so often supplemented 3. But it’s not for its amino acid protein-building qualities that people crave this stuff.

Instead, it’s for its ability to boost nitric oxide production and leave you with that killer pump every lifter looks for before hitting the gym.

That pump that leaves you pushing for longer and harder than you ever have before. It’s essentially what you need to stimulate muscle growth, so it’s no question that L-citrulline should be in any fitness enthusiasts’ stack.

Aside from that, it’s also gained a fair bit of attention for its beneficial role in cardiovascular health, as well as its direct and indirect effects on skeletal muscle and adipose tissue metabolism 3.

The Role Of Glutathione And L-Citrulline

So, why do we love this power couple?

As we mentioned, L-citrulline is an awesome supplement for boosting nitric oxide production. While your endothelial cells can synthesize some NO, when we’re grinding hard at the gym, we want to ensure sufficient amounts are being produced to keep blood flowing and oxygen and nutrient delivery strong.

And because intense exercise increases the generation of free radicals and elevations in reactive oxygen species (ROS) reduce the bioavailability of NO, we want to add in supplements to enhance production 3.

However, oral supplementation of L-arginine, the precursor for NO synthesis, has been shown to be largely ineffective at increasing NO synthesis and/or bioavailability for several reasons, which makes L-citrulline much more ideal for boosting levels of L-arginine and subsequently NO.

L-citrulline serves as a reservoir of arginine in the body and is directly converted to arginine, thus indirectly boosting nitric oxide levels.

And how does glutathione fit into this equation?

As one of the most important endogenous antioxidants in the body, glutathione plays a significant role in the detoxification of endogenous metabolic products but also in stabilizing NO.

The problem with nitric oxide is that while it’s really good for vasodilation, it breaks down quickly in the bloodstream, so extending its life becomes important for getting its benefits. And research suggests that supplementing L-citrulline alongside GSH may do just that.

Studies suggest that GSH stimulates L-arginine turnover and, in the presence of GSH, nitric-oxide synthase (NOS) activity and the subsequent production of NO is increased 4.

This suggests that glutathione may be important for protecting NO against oxidation, allowing for sustained NO release. Therefore, combining L-citrulline with GSH may augment the production of nitric oxide for better overall performance.

Setria Glutathione + L-Citrulline—The Power Duo

There’s no doubt that raising nitric oxide levels can boost athletic performance, but because the stability of NO is questionable, supplementing with GSH can safeguard against breakdown due to its fundamental role in buffering nitric oxide (NO).

Skeletal muscle is a tissue that actively produces high levels of ROS and nitric oxide under certain physiological conditions, especially during exercise, which increases the need for antioxidants to neutralize radicals and prevent damage, as well as maintain levels of NO in the bloodstream.

A 2015 study published in the Journal of the International Society of Sports Nutrition looked at the effects of L-citrulline + GSH supplementation on NO levels 4.

Researchers sought to investigate the efficacy of L-citrulline and/or GSH on markers indicative of NO synthesis and found that daily oral supplementation with 200mg of Setria® Glutathione and 2g of L-citrulline enhanced levels of nitric oxide, concluding that Setria® Glutathione not only enhanced blood levels of NO, but may sustain levels by preventing its oxidative reaction when ingested in combination with L-citrulline.

And in Pre Lab Pro®, that’s precisely what you’re getting. It’s a patented formula of 7 powerful ingredients to maximize circulation for a stronger, longer-lasting nitric oxide boost and performance like you’ve never experienced before.

With every scoop you’re getting:

  • Patent-pending, research-backed 2-in-1 stack: Setria® Glutathione + L-Citrulline
  • Shown to promote an NOx boost that extends into the post-workout window
  • Sustains NOx levels in blood 2X than equivalent doses of L-Arginine or L-Citrulline alone
  • Clinically shown to reduce fatigue and accelerate recovery in resistance-trained athletes
  • Clinically shown to boost and maintain lean muscle mass when used in conjunction with resistance training
  • Clean, premium Kyowa Quality from an international world leader in supplement ingredients

It’s an ultra-modern pre-workout formula for bigger and better results.

Final Thoughts

When it comes to choosing a nitric oxide booster, you can’t go wrong with Glutathione and L-Citrulline. They’re a power duo that function to boost NO levels and sustain them for a stronger, bigger, and more powerful pump than any other supplements out there.

And in Pre Lab Pro®, you’re getting Setria® Performance Blend combined with other potent NO boosters and balancers for a cleaner, longer-lasting NO turbocharge than anything you’ve felt before.


  1. K Aquilano, S Baldelli, MR Glutathione: new roles in redox signaling for an old antioxidant.Front Pharmacol. 2014;5:196.
  2. CK Sen, M Atalay, O Hänninen. Exercise-induced oxidative stress: glutathione supplementation and deficiency. J Appl Physiol (1985). 1994;77(5):2177-2187.
  3. TD Allerton, DN Proctor, JM Stephens, TR Dugas, G Spielmann, BA Irving. l-Citrulline Supplementation: Impact on Cardiometabolic Health. 2018;10(7):921.
  4. S McKinley-Barnard, T Andre, M Morita, DS Willoughby. Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis.J Int Soc Sports Nutr. 2015;12:27.