Citrulline: an essential dietary supplement for athletes?

Highly prized by power sports enthusiasts 🏋️ and endurance athletes 🏃, citrulline is an essential amino acid with multiple benefits. Improved muscular growthThe benefits of this dietary supplement include reducing fatigue, protecting the immune system and preserving cardiovascular health. 

How it works, dosage, side effects... Find out everything you need to know before taking the plunge. supplement with citrulline.

What is citrulline?

Citrulline is a non-essential amino acidas Creatinearginine, alanine or glutamine. Unlike essential amino acids, this means it is naturally produced by the human body.

This production in the body takes place during the urea cycle. 

Citrulline is a non-protein amino acid. In other words, it is excluded from the composition of proteins. 🧬 However, this doesn't mean that it doesn't play a part in their synthesis.

Indeed, it is considered a arginine precursor. In particular, it provides the material needed to synthesize nitric oxide.¹ We'll come back to this later.

Lastly, it takes its name from a fruit, the watermelon (also known as "watermelon"). citrullus vulgaris "in Latin), a 0-calorie food particularly appreciated in summer. 🍉

In fact, watermelon is one of the citrulline-rich foodswith 0.7 to 3 grams per kilo. Cucumbers, squash, melons and pumpkins also contain less.

Given its many benefits, citrulline is present in the vast majority of food products. pre-workout on the market.

What are the benefits of citrulline?

Let's now turn our attention to benefits of this substance. 🙏

Improved resistance to stress

Citrulline boosts resistance to effort and energy.endurance.^{2 3}

By being a precursor of arginine, it promotes the blood flow 🩸 and helps muscles oxygenate better.

It strengthens the cardiovascular systemby helping to synthesize nitrogen nitrites (NO). The latter play an important role in determining the volume of blood ejected into the arteries.

This set of reactions helps to delay the onset of muscle fatigue 😫 and, by extension, to improve physical performance.

In power sports such as strength trainingA greater resistance to effort is ideal for better muscle development.

Accelerated post-workout recovery

This amino acid is also involved in the transformation of excess ammonia into urea (which is then excreted in the urine), freeing the body of ammonia. toxins.

For athletes, this means muscle recovery faster and less painful after training.^{4 5}

Improved muscle anabolism

Citrulline supplementation helps to stimulate the protein synthesisand therefore promotes anabolism.^{6 7}

As a reminder, muscle anabolism refers to the phase during which muscle building occurs. 💪

It would also increase growth hormone production.

Preventing sarcopenia in the elderly

In addition to its effects on endurance and muscle gain, citrulline also helps the body delay the onset of sarcopenia. This pathology results in a progressive loss of strength and muscle mass. It mainly affects people over 50.

This is made possible by its intervention in protein synthesis in skeletal muscle.^{8 9}

Boosting the immune system

Last but not least, citrulline helps to improve the body's immune system. health. 🫀

Its action strengthens the immune system and reduces blood pressure.

Citrulline dietary supplements

As you can see, citrulline exists in the form of food supplements. Let's take a closer look.

Which citrulline to choose?

There are 2 types of citrulline supplements: 

• The L-citrullinewhich is the purest form of citrulline.
• The citrulline malatein which citrulline is combined with malic acid, a substance found in certain fruits.

🤔 But then, what's the most effective form for improving your endurance and promoting muscle mass gain?

While some studies have suggested that citrulline malate provides a better absorption others believe that its contribution is more limited.

More research is needed to find out which version is really the best.

When to take it and at what dosage?

With regard to the dosage L-citrulline or citrulline malate, it is recommended to consume between 3 and 6 grams a day, a sufficient quantity to benefit from its advantages.

You can divide this intake into 2 doses, making sure you take one approximately 1 hour before your workout.

The first effects of citrulline will be felt after just a few days. Available in powder or in capsules 💊, this dietary supplement must be consumed over time to be truly effective.

What are the side effects?

Citrulline is safe. ✅

No side effect no adverse effects have been observed, not even digestive disorders or headaches.

Citrulline or arginine: how to choose?

Arginine is also available in supplement form, how do you choose between these two substances with similar properties?

Most experts in sports nutrition agree that the benefits of citrulline are more pronounced than those of arginine.

In fact, the liver tends to degrade arginine more than citrulline during its passage, which limits its effects on the body.¹⁰

Conclusion

Although citrulline is not directly involved in protein construction, it is nonetheless interesting for its role as an arginine precursor. By improving endurance and recovery, citrulline helps to optimize physical performance athletes. 🙌

Notes and references

1. Arginine and the innate immune response - Beyond nitric oxide production. Virginie Mieulet, Richard F. Lamb. Med Sci (Paris) 27 (5) 461-463 (2011). DOI: 10.1051/medsci/2011275005 ︎
2. Suzuki T, Morita M, Kobayashi Y, Kamimura A. Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study. J Int Soc Sports Nutr. 2016 Feb 19;13:6. doi: 10.1186/s12970-016-0117-z. PMID: 26900386; PMCID: PMC4759860. ︎
3. Figueroa A, Wong A, Jaime SJ, Gonzales JU. Influence of L-citrulline and watermelon supplementation on vascular function and exercise performance. Curr Opin Clin Nutr Metab Care. 2017 Jan;20(1):92-98. doi: 10.1097/MCO.0000000000000340. PMID: 27749691. ︎
4. Callis A, Magnan de Bornier B, Serrano JJ, Bellet H, Saumade R. Activity of citrulline malate on acid-base balance and blood ammonia and amino acid levels. Study in the animal and in man. Arzneimittelforschung. 1991 Jun;41(6):660-3. PMID: 1930358. ︎
5. Rhim HC, Kim SJ, Park J, Jang KM. Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis. J Sport Health Sci. 2020 Dec;9(6):553-561. doi: 10.1016/j.jshs.2020.02.003. Epub 2020 Feb 8. PMID: 33308806; PMCID: PMC7749242. ︎
6. Jourdan M, Nair KS, Carter RE, Schimke J, Ford GC, Marc J, Aussel C, Cynober L. Citrulline stimulates muscle protein synthesis in the post-absorptive state in healthy people fed a low-protein diet - A pilot study. Clin Nutr. 2015 Jun;34(3):449-56. doi: 10.1016/j.clnu.2014.04.019. Epub 2014 May 4. PMID: 24972455; PMCID: PMC4309748. ︎
7. C. Moinard, M. Jourdan, S. Walrand, S. Le Plenier, Y. Boirie, L. Cynober. Citrulline has a direct effect on muscle protein synthesis. Nutrition Clinique et Métabolisme, volume 21, Supplement 2, 2007, Pages 31-32, ISSN 0985-0562. ︎
8. Luc Cynober. Citrulline supplementation in sarcopeniaVolume 5989, Issue 55, 07/2018, Pages 1-48, ISSN 1766-7305. ︎
9. Bahri S, Zerrouk N, Aussel C, Moinard C, Crenn P, Curis E, Chaumeil JC, Cynober L, Sfar S. Citrulline: from metabolism to therapeutic use. Nutrition. 2013 Mar;29(3):479-84. doi: 10.1016/j.nut.2012.07.002. Epub 2012 Sep 28. PMID: 23022123. ︎
10. Agarwal U, Didelija IC, Yuan Y, Wang X, Marini JC. Supplemental Citrulline Is More Efficient Than Arginine in Increasing Systemic Arginine Availability in Mice. J Nutr. 2017 Apr;147(4):596-602. doi: 10.3945/jn.116.240382. Epub 2017 Feb 8. PMID: 28179487; PMCID: PMC5368575. ︎