Citrulline Uses and Benefits For Bodybuilding

Citrulline Uses and Benefits For Bodybuilding

How Can Citrulline Improve Athletic Performance? Read on to find out more.

Author: Nicola Joyce is a member of the National Union of Journalists and the Fitness Writers Association.

LAST UPDATED: April 2019 by Ben.

This review of citrulline is supported by scientific studies references at the footer of the page.

Amino Acids and Fitness

The amino acid l-citrulline can help you get better results from your training.

Here’s what you need to know about citrulline…

Go Further

We’re all here for the same reason: because we want to be bigger, better, and stronger.

But are you maximizing how you use simple, natural supplements?

If you’re not using citrulline, you could be missing a trick.

Read on to discover more about this amino acid and how it can boost your training performance so you can make better gains.

What Is Citrulline?

Citrulline is one of the non-essential amino acids. As you may know, amino acids are considered the “building blocks” of protein.

They are crucial for building, maintaining, and repairing all tissue and cells, including muscle.

In the human body, the kidneys convert l-citrulline into the amino acid called l-arginine plus the chemical called nitric oxide (NO).

Arginine is an essential precursor for NO and creatine.

However, citrulline is actually more effective in increasing l-arginine than l-arginine supplementation itself.

Importance of Citrulline?

Citrulline is non-essential, which means we don’t need to get it from food or from supplements.

But that’s not to say that it isn’t beneficial.

It’s no coincidence that l-citrulline is a key ingredient in leading pre-workouts and intra-workout blends.

If you train frequently and intensely, or if you are concerned about your cardiovascular health (or have a family history of poor blood vessel function), citrulline supplements could help your heart, blood, and CV system function more optimally.

For such a cheap supplement, it’s certainly worth a try.

Citrulline vs. Arginine

Supplementing with arginine will increase plasma arginine, but citrulline supplementation increases it for longer.

Arginine is predominantly used by the liver, whereas citrulline can be taken up by the entire body.

You’ve probably heard of nitric oxide (NO) as a performance enhancing ingredient in many pre-workouts.

Citrulline’s role in NO production should tell you why it’s important to training performance.

You’ll find citrulline supplements referred to as l-citrulline (which is the free form version of the amino acid) or citrulline malate (which is the amino acid, attached to a magic acid molecule).

What Foods Contain Citrulline?

Fun fact: the name citrulline comes from the Latin word “citrullus”, meaning watermelon.

Go to the top of the class if you deduced that watermelon is naturally high in citrulline.

In fact, watermelon is the only food source significantly high in citrulline.

So unless you’re a watermelon super-fan (and prepared to eat a lot of it all year round), you’ll need to supplement with a citrulline product.

You’d need to eat around 3.3kg watermelon to get the equivalent of 10g supplemental l-arginine. [1]

How Much Citrulline For Athletic Performance Benefit?

There have been plenty of studies into the effects on citrulline on athletic performance, but none of them give a standardized recommendation for intake.

For example, this is an old study (1985) but it looked at the role of citrulline and arginine in stimulating nitric oxide synthesis during intense exercise.

The dose was done on bodyweight, but translated to around 0.08g/kg bodyweight of citrulline.

This study showed that citrulline supplementation improved the athletes’ tolerance to intense exercise, and helped them do more work.

It concluded that short-term citrulline supplementation may have a positive impact on blood pressure, and improve training performance. [2]

Another study found that supplementing with 8g citrulline one hour before training resulted in an increase in resistance training performance, lowered RPE during upper body training, and seemed to decrease DOMS after the training session. [3]

Citrulline And Weight Training

Various studies suggest that supplementing with citrulline may reduce muscle soreness or DOMS during the 24-48 period after training.

Furthermore, it can delay fatigue and RPE so you can increase the load, volume, or intensity of your sessions.

How Does Citrulline Impact Bodybuilding?

Citrulline plays an important role in heart health, blood vessel health, and immune system strength.

Its cardiovascular effects help optimize blood flow, meaning you’ll be able to train harder, offset fatigue, and fill muscle cells with more blood.

This doesn’t just mean a good pump (although that’s important!) Cell swelling is key for hypertrophy and muscle gain over time.

Citrulline produces nitric oxide in the body, and this dilates blood vessels to boost oxygen and nutrients to your working muscles, and help with the removal of metabolic waste.

Think of citrulline as the amino acid which kickstarts a series of performance-boosting functions which help your muscles work better, grow more, and recover faster.

Effective Dose Of Citrulline

As we’ve said, there’s no single accepted recommendation for dosing citrulline.

All the studies so far base their doses on individual body weight, rather than on a blanket amount.

The current thinking is 0.08-18g citrulline per kg bodyweight per day (but the cycling study, referenced above, suggests a general dose of 6g citrulline per day).

This is a really wide spectrum, so we suggest that you experiment with dosing your own citrulline (starting at the low end to assess tolerance and effectiveness).

Citrulline supplements are available as citrulline powder, which you can mix with your own pre workout, or as citrulline capsules or tablets.

Citrulline is also present in a lot of popular pre workouts, alone or in conjunction with arginine.

Is Timing Key To Taking Citrulline?

Timing is likely to be important for taking citrulline supplements.

When you take citrulline before a weights workout, the lowering effect on your blood pressure will lead to a better pump, because more blood will l get to your muscles.

And, since the main benefit is boosting circulation and increasing training endurance, the best time to take your citrulline is probably 60-30 minutes before training.

Using it as a pre-workout, or within a pre-workout blend, is the most obvious way to use this cheap and effective amino acid supplement.

Make Your Own Pre-Workout

Citrulline is a popular ingredient for homemade pre-workout drinks. Here are a few combinations which will boost energy, sharpen your focus, and open up those blood vessels for a better pump, good nutrient uptake, and faster recovery.

Option 1

5g caffeine monohydrate

200mg caffeine

6g citrulline malate

2g beta alanine

Option 2

100-300mg caffeine

5g creatine

4g beta alanine

6g citrulline malate

Option 3

20g-40g carbs in liquid or high GI form

A cup of strong black coffee

2g beta alanine

BCAAs containing 4g leucine

5g creatine

6g citrulline malate


Citrulline is not an essential nutrients, however, if you want to get the most from your training, it is not to be ignored.

It can increase nitric oxide production which dilates the blood vessels meaning more oxygen and other nutrients can replenish your muscles and organs so they can work more effectively.

As a cheap supplement, or if you fancy eating masses of watermelon, it is a nutrient that can improve your overall performance.


[1] Elevated plasma citrulline and arginine due to consumption of Citrullus vulgaris (watermelon). Mandel H, Levy N, Izkovitch S, Korman SH. J Inherit Metab Dis. 005;28(4):467-72. PMID: 15902549

[2] l-Citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans. Bailey SJ, Blackwell JR, Lord T, Vanhatalo A, Winyard PG, Jones AM. J Appl Physiol (1985). 2015 Aug 15;119(4):385-95. doi: 10.1152/japplphysiol.00192.2014. Epub 2015 May 28. PMID: 26023227

[3] Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. Pérez-Guisado J, Jakeman PM. J Strength Cond Res. 2010 May;24(5):1215-22. doi: 10.1519/JSC.0b013e3181cb28e0. PMID: 20386132

Article by:

Nicola Joyce (aka “the fit writer”) is a fitness industry copywriter who has been writing for and about sport and fitness since 2004. Nicola is a competitive drug-free bodybuilder (with two World titles at amateur level) and has also competed in powerlifting and a couple of strongman comps. Prior to her strength training days, Nicola was an endurance athlete and has even swum the English Channel twice. She can be found on all social media at: thefitwriter.


Citrulline benefits and uses
Article Name
Citrulline benefits and uses
This article looks at the benefits and uses for athletic performance.

Ben BA(Hons), PGCert

Ben established this site to be a free resource in 2015. Since then it has gained over half a million visits. He has always been interested in sport and he started playing rugby at the age of 6 represented his town, county and school. Ben also enjoys cycling, has started skiing and is in the Army Reserve representing his Regiment as part of the 150 Regimental Shooting Team. He holds a bachelor's and postgraduate degree in sport exercise & nutrition.

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