L Arginine vs L Citrulline: Which Supplement Is Best?



After protein powder and creatine, pre-workout dietary supplements are arguably the preferred class of dietary dietary supplements. Pre-workout dietary supplements are a broad vary of merchandise that may embrace a wide range of pure components, together with creatine and amino acids.

Two of the most typical components utilized in pre-workout dietary dietary supplements are the nonessential amino acids L-citrulline and L-arginine. Citrulline and L-arginine are amino acids accountable for nitric oxide manufacturing, which helps enhance blood circulation.

Nitric oxide boosters are the most typical and efficient pre-workout dietary supplements, so citrulline and L-arginine are the right components. On this article, we are going to dive into analysis to match L-arginine vs. L-citrulline that will help you decide which amino acid is the very best for dietary dietary supplements. 

Desk of Contents:

  • What Is L Citrulline?
  • What Is L Arginine?
  • L Arginine & L Citrulline: What’s The Relationship?
  • What Are The Advantages Of L Arginine & Citrulline Dietary supplements?
  • Aspect Results
  • How A lot L-Arginine And L-Citrulline Ought to I Take?
  • Can You Take L-Arginine And L-Citrulline Collectively?
  • Which Is Higher, L-Arginine Or L-Citrulline?
  • FAQs

What’s L citrulline?

L-citrulline is an amino acid that exists naturally within the physique and is obtained by way of sure meals. Citrulline is a non important amino acid since it’s produced within the physique through the urea cycle. L-citrulline is a often called a precursor to the amino acid L-arginine, which additionally performs an important function within the urea cycle.

The urea cycle is the method within the liver that converts the extremely poisonous chemical ammonia into urea (urine) to take away waste from the physique. Except for the urea cycle, L-citrulline additionally performs a big function in nitric oxide synthesis. Nitric oxide is necessary as a result of it helps blood vessels chill out and widen, which improves blood circulation and circulation. This causes blood stress ranges to drop, which helps enhance athletic efficiency and results in a number of different advantages, which we are going to discover beneath. 

L-citrulline has a variety of makes use of within the dietary supplementation world. Its most typical use is by athletes and gym-goers to extend endurance and scale back fatigue to enhance efficiency. It’s generally utilized in pre-workout supplements to extend nitric oxide manufacturing, which helps improve “the pump.”

Citrulline dietary supplements can be found in varied varieties, however it’s mostly in powder or capsule type. Citrulline dietary supplements are available two varieties: 

  • L-Citrulline: Common citrulline amino acid.
  • Citrulline Malate: Citrulline mixed with malic acid (malate). Malate is significant for ATP manufacturing, which is the physique’s vitality supply. Most pre-workout and sports activities dietary supplements use citrulline malate to offer further vitality. 

It can be present in sure meals, with watermelon containing the very best quantity, significantly within the white rind close to the pores and skin. Different meals that comprise citrulline embrace squash, pumpkins, melons, nuts, legumes, and lots of protein-rich meals corresponding to poultry, beef, and pork. 

What’s L Arginine?

L-arginine is considered one of twenty amino acids which might be the constructing blocks of all of the physique’s proteins. There are 9 important amino acids that the physique doesn’t produce naturally and, due to this fact, must be obtained by way of meals and dietary dietary supplements.

L-arginine is taken into account a semi-essential amino acid or conditionally important as a result of wholesome topics can usually produce it below common circumstances, however there are conditions, like once you’re sick or pressured, when the physique can’t produce it. In the event you’re ever involved about not producing sufficient amino acids, ask your physician a few plasma amino acids check.

Like L-citrulline, arginine performs a big function in nitric oxide manufacturing. As soon as the physique obtains arginine, a household of enzymes referred to as nitric oxide synthase (NOS) converts the arginine into nitric oxide and L-citrulline. The nitric oxide relaxes, or widens, the blood vessels, resulting in a number of well being advantages. Moreover nitric oxide manufacturing, arginine can observe the arginase pathway, which is when arginine is damaged down into urea for the urea cycle. 

Arginine will be obtained in lots of high protein low fat foods, corresponding to hen, seafood, soy, entire grains, and dairy merchandise. Arginine dietary supplements are available varied varieties together with liquid, powder, and capsules. It’s used equally to citrulline, significantly as a pre-workout complement to advertise nitric oxide synthesis.

L Arginine vs L Citrulline: What’s The Relationship?

L-arginine and citrulline have a cyclical relationship with one another and the amino acid ornithine. The first connection between l citrulline and arginine begins with the urea cycle. When amino acids break down, they launch ammonia, which is extremely poisonous to the physique. This course of removes poisonous ammonia from the physique by changing it into urea, which then is excreted in urine. 

Arginine degradation leads to the manufacturing of the amino acid ornithine. Ornithine removes ammonia and detoxes the blood in a response that produces citrulline. The citrulline is then transformed into arginine within the kidneys, then damaged down into urea and excreted as urine. Throughout this course of, the arginine additionally releases ornithine, which causes the cycle to begin over. The method of breaking arginine down into urea and ornithine known as the arginase pathway.

Arginine may also observe the nitric oxide synthase pathway, which is the method for nitric oxide manufacturing. Throughout this course of, nitric oxide synthase catalyzes arginine into nitric oxide and citrulline. This course of demonstrates how arginine will be transformed into citrulline, and citrulline will be transformed into arginine through the urea cycle. 

To summarize, citrulline is fashioned from the amino acid ornithine in the beginning of the urea cycle. Citrulline then converts into arginine, which helps produce urea that’s excreted in urine. Throughout arginine’s conversion to urea, it additionally releases ornithine, triggering the cycle once more. Conversely, the nitric oxide synthase pathway can convert arginine into citrulline. 

What Are The Advantages Of L Arginine Dietary supplements?

As you’ll discover, nearly all of advantages from L-arginine come from its potential to extend nitric oxide manufacturing. Under are a few of the high advantages of L-arginine dietary supplements: 

1) Improve train efficiency:

One of many major causes that folks use L-arginine is to enhance efficiency throughout excessive depth train. L-arginine promotes nitric oxide manufacturing, which helps enhance muscle blood circulation.

Research present that improved blood circulation will help ship vitamins faster and take away waste from the muscle groups, increasing muscular endurance and lowering fatigue. A scientific overview of 18 research concluded that arginine supplementation considerably improved cardio or anaerobic efficiency1.

2) Enhance cardiovascular well being:

One other advantage of arginine associated to the manufacturing of nitric acid is improved cardiovascular well being. Nitric acid causes blood vessels to chill out, bettering blood circulation.

On this case, the rise in blood circulation helps enhance circulation and decrease blood stress. Research present arginine supplementation will help within the therapy of assorted cardiovascular problems and hypertension2.

3) Deal with Erectile Dysfunction:

One of many advantages of each L arginine and citrulline is that it may enhance erectile dysfunction.

A overview of ten trials confirmed oral arginine led to important enhancements in erectile perform, total satisfaction, and orgasmic perform in comparison with the placebo group. They concluded that arginine can successfully deal with delicate to reasonable erectile dysfunction3.

4) Might improve testosterone:

Research have proven that arginine can improve testosterone in animals; nevertheless, it doesn’t in people straight. Though arginine doesn’t straight improve testosterone, it may not directly stimulate testosterone manufacturing by bettering blood circulation and rising nitric oxide manufacturing.

To be taught extra concerning the relationship between L arginine and testosterone, try our article: Does L Arginine Increase Testosterone?

5) Enhance Immune perform:

Arginine has an impact on varied components of the physique, together with the immune system. Analysis means that L-arginine will help enhance immune perform and stop illness.

What Are The Advantages Of Citrulline Dietary supplements?

Citrulline supplementation has practically equivalent advantages to arginine, which is smart, contemplating they’re comparable. The advantages of citrulline barely outweigh these of arginine as a result of it’s extra environment friendly at nitric oxide manufacturing. Advantages of citrulline supplementation embrace:

1) Improve train efficiency:

A overview of eight research discovered that six to eight grams of citrulline supplementation 40-60 minutes earlier than bodily efficiency led to will increase in repetitions in comparison with a placebo.

They concluded that citrulline supplementation can delay fatigue and improve muscle endurance throughout excessive depth train4

2) Scale back muscle soreness:

One other advantage of citrulline that’s helpful to athletes is its potential to assist scale back muscle soreness and help muscle recovery. A scientific overview analyzed the impact that citrulline supplementation has on extra soreness and blood lactate ranges post-exercise.

They discovered that consuming three to 4 grams of L-citrulline, or 8 grams of citrulline malate, one hour earlier than train led to a considerably decrease score of perceived exertion and muscle soreness 24- and 48-hours post-exercise5.

3) Enhance cardiometabolic well being:

Like arginine, citrulline additionally helps enhance cardiovascular well being and associated problems. Diminished ranges of nitric acid can result in a number of age- and lifestyle-related ailments, together with hypertension, sort 2 diabetes, insulin resistance, and heart problems.

Research present {that a} minimal efficient dose of three grams of L-citrulline as much as the utmost efficient dose of 10 grams each day will help scale back the danger of such cardiometabolic problems by rising nitric oxide ranges6.

4) Deal with Erectile Dysfunction:

Additionally, like arginine, citrulline can be utilized as a pure solution to deal with erectile dysfunction. One examine examined the results that 1.5 grams each day of oral L-citrulline supplementation had on bettering signs of erectile dysfunction.

The outcomes confirmed important enhancements in erection hardness and therapy satisfaction with oral L-citrulline7.

5) Enhance insulin sensitivity:

One examine examined the results of citrulline supplementation on bettering insulin sensitivity in rats. The outcomes confirmed that consuming L-citrulline each day for eight weeks improved insulin resistance related to enhanced insulin sensitivity.

There’s a want for extra complete analysis in people, however the outcomes are promising8.

Arginine vs Citrulline: Aspect Results

Most individuals don’t expertise negative effects with arginine or citrulline, and in the event that they do, they’re often delicate. The most typical negative effects are gastrointestinal misery. To keep away from negative effects, keep away from consuming greater than 9 grams each day of L-arginine or 8 grams of L-citrulline. 

Potential negative effects:

  • Bloating
  • Abdomen discomfort
  • Diarrhea
  • Belly ache
  • Nausea
  • Complications
  • Allergic response
  • Gout 

Each amino acids can work together with sure medicines or circumstances. Some medicines and folks that ought to keep away from taking arginine and citrulline embrace:

  • Individuals with low blood stress
  • Erectile dysfunction remedy
  • Nitrates
  • Blood thinners
  • Gastroesophageal reflux illness (GERD) or acid reflux disease
  • Diuretics
  • Diabetes remedy

How A lot L-arginine And L-citrulline Ought to I Take?

The dosage of L-arginine or L-citrulline will rely in your cause for taking it and your required targets. A common rule of thumb is that arginine may have twice the dosage as citrulline since citrulline is roughly twice as potent.

For each 1.75 grams of citrulline malate, there’s 1.0 gram of citrulline and 0.75 grams of malate. Due to this fact, the dosage for citrulline malate is almost double that of L-citrulline. 




Total Well being


2-6 grams each day



1-3 grams each day


Citrulline Malate

8 grams each day

Improved Athletic Efficiency


5-9 grams 40-60 minutes earlier than train



2-6 grams 40-60 minutes earlier than train


Citrulline Malate

6-8 grams 40-60 minutes earlier than train

Erectile Dysfunction


1.5-5 grams each day



3 grams (one gram taken thrice each day)

Blood Stress


6-10+ grams each day



3-6 grams each day

Can You Take L Arginine And L Citrulline Collectively?

Sure, ideally, arginine and l citrulline needs to be taken collectively. Nevertheless, should you solely need to decide one to begin with, you’ll be higher off selecting L-citrulline. However, take into account, analysis reveals that arginine and citrulline have a synergistic impact, working collectively to extend plasma concentrations of nitric oxide far better than they will individually.

A examine utilizing rats and New Zealand white rabbits in contrast oral arginine supplementation, citrulline supplementation, and a mix of each. The outcomes confirmed that taking citrulline and arginine collectively precipitated a extra fast improve in plasma arginine focus and enhanced nitric oxide metabolism9.

Contemplating they work considerably higher when used collectively, it will be greatest to take each, ideally in a single product. It is usually much more cost-efficient to buy a mix product that comprises each arginine and citrulline slightly than the person amino acids.

For instance, a bottle of Nutricost L-Arginine is corresponding to a bottle of Nutricost L-Arginine + L-Citrulline. You do not pay extra for the product that has each in it.

citrulline vs arginine

Citrulline vs Arginine: Which Is Higher?

As I briefly talked about above, L-citrulline is barely higher than L-arginine as a result of it produces extra nitric oxide and will increase arginine availability. One examine in contrast L-citrulline and L-arginine for his or her effectivity in rising arginine availability in mice. The outcomes confirmed that citrulline supplementation led to the next plasma arginine focus than arginine.

Arginine elevated plasma arginine focus from 109 mol/L to 159, whereas citrulline elevated plasma arginine focus from 109 mol/L to 21410. Different analysis confirms that citrulline is roughly twice as potent as arginine in relation to rising plasma focus11

Ideally, it is best to take a product with each arginine and citrulline to maximise advantages, but when it’s a must to select between the 2, decide L-citrulline. The vast majority of probably the most well-known pre-workout merchandise comprise citrulline malate. One of the best L-citrulline complement is Cellucor C4. C4 is a mix of citrulline malate, creatine, caffeine, and CarnoSyn Beta-alanine, designed to enhance your vitality, endurance, and focus.

l arginine vs l citrulline

C4 Authentic is constructed to take your vitality, muscular endurance, and pumps to the following stage. Starting from novices all the way in which as much as the elite opponents, C4 pre-workout merchandise ignite…

One of the best L-arginine complement accessible is NOW Supplements L-Arginine. Every serving comprises 1 gram of high-quality L-arginine from a extremely respected complement producer. 


On this part, we are going to reply a few of the most typical questions associated to L-arginine vs. L-citrulline.

Does L-citrulline improve testosterone?

Citrulline doesn’t straight improve testosterone. Nevertheless, it might not directly assist improve testosterone. In the event you’re concerned about rising your T-levels, try our article: How To Boost Testosterone Naturally.

What ought to I not combine with L-arginine?

Sure medicines don’t combine with L-arginine, together with blood stress medicines, blood thinners, nitroglycerine, and diuretics. 

Is it OK to take L-citrulline daily?

Sure, it’s endorsed to take L-citrulline daily to maximise well being advantages. Ensure that to begin on the lowest efficient dosage. 

Do you want to cycle L-arginine?

Sure, L-arginine needs to be cycled each two months by taking two months off. You may repeat the cycle should you take day without work in between. 

Is citrulline higher than creatine?

Citrulline could also be higher than creatine for pre-workout as a result of it will increase nitric oxide and will increase blood circulation, which will help get a greater pump. Nevertheless, creatine is best for constructing power and mass. 

How briskly does l-arginine work?

It takes roughly thirty to sixty minutes for L-arginine to work, which is why folks use it about an hour previous to train. 

Does citrulline burn fats?

Citrulline will help burn fats not directly. It will increase train efficiency, which permits folks to have extra environment friendly exercises. Citrulline additionally will help enhance insulin sensitivity, which is significant for sustaining blood sugar management and burning fats. 

Why do bodybuilders use L-arginine?

L-arginine gives a number of key advantages to bodybuilders, together with elevated nitric oxide manufacturing, improved efficiency, decreased soreness, and it might assist improve testosterone not directly. 

L Arginine vs l citrulline: Closing Takeaways

When evaluating l-citrulline vs. l-arginine, you’ll discover a number of similarities as a result of the amino acids are so carefully associated. L-citrulline is a precursor to L-arginine as a result of it converts through the urea cycle to assist the physique take away waste. Conversely, arginine can observe the nitric oxide synthase pathway, which is the method of nitric oxide manufacturing.

Throughout this course of, nitric oxide synthase catalyzes arginine into nitric oxide and citrulline. These two processes are very important for sustaining total well being and rising nitric oxide, which is useful for athletic efficiency. Research have proven that citrulline supplementation is extra environment friendly at rising plasma arginine focus than arginine itself. Citrulline is roughly twice as potent as arginine, which is why citrulline is extra generally used for train and located in pre-workout dietary supplements. 

Research have proven a synergistic impact with L-arginine and L-citrulline, as combining each is best than every amino acid. Ideally, it is best to select a product that comprises each to maximise nitric oxide manufacturing and improve blood circulation. Nevertheless, if it’s a must to select between the 2, L-citrulline is the higher complement for bettering efficiency. Pre-workout merchandise usually use citrulline malate for an added vitality enhance, so make sure to take note of the dosages.

To study the very best dietary supplements containing l arginine and l citrulline, try our articles: 7 Best Nitric Oxide Supplements To Pump You Up and 7 Best Pump Pre-Workout Supplements!

l citrulline vs l arginine erectile dysfunction


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