Citrulline Malate for Endurance: An Amazing Supplement

Many athletes are taking citrulline malate for endurance.  This supplement continues to grow in popularity and is found in many products nationwide.  If you are looking for information on citrulline malate supplementation and its benefits for endurance athletes, look no further.  We did the research, so you don’t have to.

What is Citrulline Malate?

citrulline malate for endurance

Citrulline malate is L-Citrulline combined with malic acid.  L-citrulline is a naturally occurring amino acid found in food such as watermelon (Kaore et al., 2013).  Our bodies also make L-citrulline.  Our bodies change L-citrulline into another amino acid, L-arginine, and a chemical called nitric oxide (NO).  +

Malic acid is an acid made by all living organisms, and it contributes to the sour taste of many fruits and is often used as a food additive.  L-citrulline and malic acid, when combined, make citrulline malate, which, in turn, makes it more bioavailable when ingested.

Why Does Any of That Matter?

After that paragraph, you must be wondering, what does all that mean?  To understand why citrulline malate is made, you must understand the benefits of citrulline malate supplementation.  As always, I will first break down the benefits for you.  Feel free to skip over the scientific literature review if you want.

The benefits of citrulline malate for endurance and ultra-endurance athletes are as follows:

  • Increases NO in the body (more on this below)
  • Reduces fatigue (increased time to exhaustion) 
    • This leads to increased training volume and exercise capacity.
  • Reduces muscle fatigue and decreases the soreness of muscles
  • Decreases rating of perceived effort/exertion (RPE)

There are more benefits, but they don’t really translate to needs specifically for endurance athletes.  If you want to learn more about other benefits of citrulline malate, feel free to check out this website. Now, if you want to learn about the research behind these conclusions, read this next section!  I promise not to bore you too much!

The Research:

Increased NO

Beets boost NO levelsFirst, I want to talk about NO levels and how they relate to endurance sports.  NO’s importance to athletes lies in its ability to regulate the delivery of oxygen to muscles.  This is done by relaxing and opening blood vessels, which improves blood flow.  In turn, better blood flow supports a muscle’s ability to contract and transport lactic acid out of the muscles (this reduces muscle soreness). 

Many endurance and ultra-endurance athletes drink or take beetroot juice supplements (personally, I’m not too fond of the taste).  This is because beetroot naturally contains high levels of nitrate (NO3).  I bet you can see where this is heading, but let me spell it out for you.  Once someone ingests NO3, the body reduces it to Nitrite (NO2) in the mouth and then to nitric oxide (NO) in the stomach (Dominguez et al., 2017). 

Sounds like a pretty involved process, am I right?  Many people don’t realize that when you supplement citrulline malate, you are increasing arginine levels (which happen to be a direct source for NO). 

In fact, citrulline malate increases arginine more than taking an arginine supplement.  The two processes both lead to increased NO levels. They simply take different paths.  Ochai et al. (2012) showed that citrulline malate consumption significantly increased NO levels (short-term) in participants compared to placebo.  

All the other Benefits

Supplementation of citrulline malate during a weight lifting protocol (in which the participants performed as many reps as possible until they were too fatigued to continue for multiple sets) delayed fatigue and promoted more reps performed per set for all sets, except the first two (Perez-Guisado & Jakeman, 2010).  Additionally, the participants reported a reduction in post-workout muscle soreness.

Another study found that citrulline malate consumption led to a significantly higher number of repetitions performed before exhaustion, as well as a significant reduction in RPE (rate of perceived exertion) versus placebo (Glenn et al., 2017).  In a systematic review, researchers noted that in 13 studies with over 204 participants, citrulline malate supplementation significantly reduced RPE and muscle soreness 24 hours and 48 hours post-workout (Rhim et al., 2020).

How Should Citrulline Malate be Supplemented?

Most of the research uses 8g doses to test results.  Many supplements contain anywhere from 6-8g.  High doses of citrulline malate have not been linked to an upset stomach.

Arginine supplements have been shown to cause digestive issues when taken in large doses.  Not coincidentally, T-30 (our daily endurance supplement) contains 8g of citrulline malate.  Isn’t it crazy how all the ingredients in these products are in scientifically appropriate doses (that was complete sarcasm in case you missed it)?

Really though, we have researched these ingredients and only include scientifically proven doses.  Anyways, back to how to take this stuff.  Research has shown that on days you exercise, you should take citrulline malate before working out.  You can break it up into two smaller doses on days you don’t work out if you want.  Citrulline malate should be taken daily over extended periods of time for it to work most effectively.

Taking it one step further

T-30 takes it one step further in increasing NO levels.  In addition to containing 8g of citrulline malate, T-30 contains 200mg of N-acetylcysteine.  Research shows that N-acetylcysteine increases glutathione, which slows how quickly the body breaks down NO.  N-acetylcysteine acts synergistically when combined with citrulline malate, further improving blood flow to working muscles.T-30

Summing it Up

Research shows that citrulline malate supplementation may be beneficial for endurance athletes.  Some benefits include increased NO levels, increased time to exhaustion, reduced muscle soreness post-exercise, and decreased RPE.  Research has shown that taking high doses of citrulline malate does not cause an upset stomach.  The recommended dose of citrulline malate is anywhere between 6-8g.

T-30, our daily endurance supplement, contains 8g.  I hope I have convinced you that citrulline malate provides many benefits for endurance athletes.  Thanks for reading, and see you in the next post!

**Use common sense, and always listen to your doctor over a blog post. They know more about your personal health situation than anybody behind a keyboard. If you have underlying medical conditions, always check with your doctor before starting a new supplementation routine.

References

Domínguez, R., Cuenca, E., Maté-Muñoz, J. L., García-Fernández, P., Serra-Paya, N., Estevan, M. C., . . . Garnacho-Castaño, M. V. (2017). Effects of beetroot juice supplementation on cardiorespiratory endurance in athletes. A systematic review. Nutrients, 9(1), 43. doi: 10.3390/nu9010043. doi:10.3390/nu9010043 [doi]

Kaore, S. N., Amane, H. S., & Kaore, N. M. (2013). Citrulline: Pharmacological perspectives and its role as an emerging biomarker in the future. Fundamental & Clinical Pharmacology, 27(1), 35-50. doi:10.1111/j.1472-8206.2012.01059.x [doi]

Ochiai, M., Hayashi, T., Morita, M., Ina, K., Maeda, M., Watanabe, F., & Morishita, K. (2012). Short-term effects of L-citrulline supplementation on arterial stiffness in middle-aged men. International Journal of Cardiology, 155(2), 257-261. doi:10.1016/j.ijcard.2010.10.004 [doi]

Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. Journal of Strength and Conditioning Research, 24(5), 1215-1222. doi:10.1519/JSC.0b013e3181cb28e0 [doi]

Rhim, H. C., Kim, S. J., Park, J., & Jang, K. M. (2020). Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis. Journal of Sport and Health Science, 9(6), 553-561. doi:S2095-2546(20)30016-8 [pii]

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