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L-Citrulline Vs L-Arginine: Which Is More Effective?

Wondering about the difference between L-Citrulline vs L-Arginine? In this article, we’ll be going over these 2 “vasodilators” so you can decide if either is worthwhile for you.

In short, neither of these supplements appear to have strong vasodilatory properties. However, L-Citrulline does appear to boost exercise performance, while L-Arginine supplementation has little effect.

For this reason, we can’t recommend the use of L-Arginine. However, if you’re interested in trying L-Citrulline, we recommend using a high-quality supplement like Transparent Labs L-Citrulline.

The difference between L-Citrulline vs L-Arginine comes down to their uses for athletes. Both supplements are touted as potential NO-boosters, although only L-Citrulline appears to have vasodilatory effects. While L-Arginine has no reported effect on athletic performance, L-Citrulline does appear to be beneficial for boosting recovery and endurance performance. 

L-Citrulline Vs L-Arginine

L-Citrulline vs L-Arginine

For adults, both L-Citrulline and L-Arginine are nonessential amino acids. This means your body produces adequate amounts of both for regular bodily function. L-Arginine is produced from L-Citrulline, and is then used to form NO in the blood, as well as reforming L-Citrulline. This process is known as the Nitric Oxide Cycle

Because both of these Amino Acids are used in the production of Nitric Oxide, they are frequently marketed as “NO-boosters”. However, only Citrulline appears to be beneficial for vasodilation.

While there’s no basis for supplementation with Arginine, it does appear that L-Citrulline has some benefits for athletic performance, specifically in fatigue and endurance performance. It also may help in improving recovery.

BenefitsL-Citrulline may be beneficial for improving recovery, reducing fatigue, and improving endurance exercise performance. There’s no basis for supplementation with L-Arginine
Recommended DoseL-Citrulline should be taken at a dose of at least 3g for any effects. A higher dose of 6-8g would be more optimal.
For Citrulline Malate, we recommend a higher dose of 8g minimum. 
As there’s no basis for L-Arginine supplementation, there is no generally accepted dose. 

What Is L-Citrulline and What Are Its Potential Benefits?

While acute L-Citrulline supplementation does not appear to have a significant effect on blood flow, it still appears to have positive effects on exercise performance. It’s worth noting that these findings were also found with a suboptimal dose of 6g/day.

It should also be noted that L-Citrulline is commonly sold as Citrulline Malate. While this is the same basic supplement, it is bonded with malate. As a result, more Citrulline Malate will need to be taken to get the same effects as L-Citrulline. It’s also worth noting that the presence of malate may play a role in improving aerobic function!

Below we’ll be going over the main benefits of L-Citrulline supplementation, including its benefits on performance and recovery.

1. Reduced Fatigue & Endurance Exercise

It appears that Citrulline supplementation leads to an increase in post-exercise oxygenation rate. It’s thought that this may lead to shorter rest times being needed in between bouts of exercise, showing a correlation between Citrulline and reduced fatigue.  

This is backed up by a study in women that found acute Citrulline supplementation to reduce fatigue, leading to better exercise performance especially towards the end of the workout. 

Similarly, an increased post-exercise oxygenation rate is also thought to improve endurance performance. As a result Citrulline may be most beneficial as a supplement to assist in endurance exercise where fatigue plays a factor. 

2. Improved Recovery

Finally, Citrulline supplementation is thought to potentially help with recovery after strenuous exercise. This is thought to be caused by Citrulline supplementation either increasing nutrient delivery or improving removal of waste products in the body. However, Citrulline’s effects on muscle recovery are not fully understood. 

How to Take L-Citrulline for Best Results

How to Take L-Citrulline for Best Results?

While L-Arginine supplementation is largely considered useless, L-Citrulline does have some genuine benefits for exercise performance. Still, you may be wondering what the optimal dosage and timing is when taking L-Citrulline. 

In the study mentioned above, athletes were given 6g of L-Citrulline a day. This can be seen as a good standard dose to get some of the benefits of L-Citrulline. It appears effects will be noticeable in doses ranging from 3-10g a day. 

L-Citrulline appears to be best as a daily supplement due to its cumulative effects. However, it appears to have some acute effects as well if you want to take it directly pre-workout. In this case, we recommend taking it about an hour before your workout for optimal effects. 

As mentioned, if you’re taking Citrulline Malate, you will need to take a slightly higher dose to achieve the same effects. We recommend taking at least 8g+ of Citrulline Malate as a minimum dose to achieve noticeable ergogenic effects. 

What Is Arginine and Does It Have Positive Sport-Related Effects?

Like L-Citrulline, Arginine is commonly marketed as a vasodilator or NO-booster. These claims are unsubstantiated, and as we’ll cover below, there’s no additional proof that Arginine has any real benefit for athletes. 

As a result, we will not be including any information on how to take L-Arginine for best results, similar to the section on L-Citrulline above. As there’s no scientific data supporting the use of L-Arginine, it’s impossible to give recommendations on proper dosage and timing. 

What Is Arginine and Does It Have Positive Sport-Related Effects?

1. Does Arginine Help With Muscle Growth?

There is currently no evidence to support the hypothesis that Arginine supplementation helps with muscle growth. While arginine’s role in the Nitric Oxide cycle may be partially responsible for blood flow during exercise performance, and therefore muscle growth, supplementation will not directly help with muscle growth. 

2. Does Arginine Help Increase Training Performance?

Similar to the point above, Arginine does not appear to have any ergogenic benefits for training performance. While its role in the body does play a role in supporting training performance, additional supplementation does not appear to have any real effect. 

Best L-Citrulline Supplement

Transparent Labs L-Citrulline

Transparent Labs L-Citrulline
  • Form: Powder
  • Servings: 120
  • Suitable for Vegans: Yes
  • Servings per Container (3g): 80
  • Package Information: 240g
  • Price per Serving: ~$0.23
  • Company Founded: 2012

While we can’t recommend L-Arginine supplementation, L-Citrulline supplementation does have some notable benefits. If you’re interested in trying L-Citrulline, we recommend checking out Transparent Labs’ L-Citrulline Supplement

It should be noted that this supplement is dosed slightly too low for optimal effects. Each serving is only 2g, with at least 3g being needed for noticeable effects. With 120 servings per container, you could still take a more effective dose of 8g a day and have enough L-Citrulline to last you for a full month. 

If you’re a fan of all-natural supplements, you’ll be happy to hear that Transparent Labs’ L-Citrulline contains no unnecessary artificial ingredients. It should be noted that this supplement only comes unflavored, so it may not be the best option if you prefer flavored supplements. 

In terms of price, Transparent Labs’ L-Citrulline offers great value for money. Each 2g serving will only cost you about ~$0.15. This means a more effective 8g dose will only cost you about $0.60, making it very budget-friendly even at a higher dose. 


Which Is Better: Citrulline or L-Arginine?

In terms of supplementation, there don’t appear to be any real benefits to using Arginine. However, L-Citrulline is beneficial for reducing fatigue and improving endurance performance, making it a very popular supplement. So, in the matter of L-Arginine vs L-Citrulline, L-Citrulline is the clear winner. 

Is L-Citrulline the Same as L-Arginine?

No, while L-Citrulline and L-Arginine both play similar and valuable roles in the body as part of the Nitric Oxide cycle, they are not the same thing. It should be noted that L-Arginine supplementation does not appear to have many benefits, while L-Citrulline has been shown to have genuine ergogenic benefits. 

It should also be noted that there’s no reason to take these supplements together. If you’re planning on pairing L-Arginine and L-Citrulline, benefits will largely come from the use of L-Citrulline. 

Does L-Citrulline Increase Testosterone?

While L-Citrulline does have some benefits for boosting performance, it doesn’t appear there’s any evidence to support its use as a testosterone booster. With that being said, if you want to increase testosterone to improve recovery and support muscle growth, L-Citrulline may be able to help with these goals!

Is It Ok to Take L-Citrulline Every Day?

Yes, as a matter of fact, it appears L-Citrulline is most beneficial when it’s taken every day. It doesn’t appear there are any downsides to taking L-Citrulline every day, but if you’re concerned about potential drawbacks, be sure to consult with your doctor before beginning use. 


Is L-Citrulline better than L-Arginine? In short, yes. 

While L-Citrulline and L-Arginine play similar roles in the body, in terms of supplementation, only one of these amino acids should be considered. If you’re considering taking L-Arginine or Citrulline Malate/L-Citrulline, we strongly recommend going with Citrulline. 

If you’re interested in trying L-Citrulline, we recommend checking out Transparent Labs L-Citrulline.

Were you aware of the difference between L-Arginine and L-Citrulline? Have you ever tried L-Citrulline or L-Arginine? Let us know in the comments below!

Also read:


  1. Jahidur Rashid, et. al, “Therapeutic potential of citrulline as an arginine supplement: a clinical pharmacology review,” Paediatr Drugs. 2020 Jun; 22(3): 279–293. (2021).
  2. Benjamin Wax, et. al, “Acute Ingestion Of L-Arginine Alpha-Ketoglutarate Fails To Improve Muscular Strength And Endurance In ROTC Cadets,” International Journal of Exercise Science: Vol. 6 : Iss. 2. (2013)
  3. L. Wehrman, et. al, “EFFECTS OF L-CITRULLINE SUPPLEMENTATION ON LOCALIZED BLOOD FLOW AND POST-EXERCISE MUSCLE REOXYGENATION RATE,” International Journal of Exercise Science: Conference Proceedings: Vol. 8: Iss. 11, Article 10. (2023)
  4. Gough, L.A, et al, “A critical review of citrulline malate supplementation and exercise performance. Eur J Appl Physiol 121, 3283–3295 (2021).
  5. D. Bendahan, et. al, “Citrulline/malate promotes aerobic energy production in human exercising muscle,” British Journal of Sports Medicine 2002;36: 282-289.

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Jacek Szymanowski

Author: Jacek Szymanowski

Certified Nutritionist,
M.Sc.Eng. Biotechnology
Performance Architect,
Strength and Conditioning Specialist

Experience: 20 years

With over 30 years of fighting experience, specialization in nutrition coaching for athletes, and expertise in metabolic health and dietary strategies, Jacek offers a comprehensive approach to optimizing your performance and well-being. Backed by a Master of Science degree in Biotechnology, Jacek remains at the forefront of scientific advancements, ensuring that his coaching is always evidence-based and up-to-date.

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