L-Citrulline is quickly gaining popularity among the supplement community due to its various health and performance benefits, such as increased blood flow, reduced fatigue, and enhanced muscle growth.

For those wanting to take their performance to the next level, keep reading to uncover how L-Citrulline works, its benefits, dosage recommendations, potential side effects, and the difference between L-Citrulline and Citrulline Malate.

What is L-Citrulline?

L-Citrulline is a neutral, non-essential amino acid that is an important component of the urea cycle in the liver and kidneys. As a non-protein amino acid, L-Citrulline is rarely found in food but is highly concentrated in watermelon.

The two most common forms of Citrulline are L-citrulline and Citrulline malate. L-Citrulline plays a critical role in the body's urea cycle, which helps eliminate ammonia, a toxic byproduct of protein metabolism.

In addition, citrulline supplementation increases the body's arginine levels, the primary substrate for the synthesis of nitric oxide; therefore, citrulline ingestion can indirectly increase nitric oxide production.

Increased levels of nitric oxide can potentially enhance circulatory health, muscle function, and reduce fatigue. This is due to nitric oxide's role in vasodilation, mitochondrial respiration, calcium handling, and glucose uptake.

What about L-Citrulline vs Citrulline Malate?

Citrulline malate combines L-Citrulline and malic acid, a naturally occurring organic acid in many fruits. Malate is less expensive than L-Citrulline and is added to improve the body's absorption and utilization of Citrulline.

In addition, supplementing with malate could increase ATP production, potentiating L-citrulline's ergogenic effects. Although there has been some promising research showing that citrulline malate can improve exercise performance, it is still being determined whether citrulline malate is superior to L-Citrulline, as there is limited research that directly compares the two.

Health and Performance Benefits of L-Citrulline

Increased Blood Flow: L-Citrulline increases blood flow, oxygen supply, and nutrients to our muscles by increasing nitric oxide (NO) production during training. NO is a gas molecule that helps dilate/relax our blood vessels, making it the perfect ingredient for 'pump' formulas.

Reduced Fatigue: Improving blood flow helps remove waste products from the muscles more efficiently, delaying the onset of fatigue. L-Citrulline has also been shown to reduce muscle soreness and improve post-workout recovery.

Muscle Growth:  L-Citrulline has also been found to stimulate muscle protein synthesis, which can help enhance muscle growth. L-Citrulline may increase the production of growth hormone, which plays a crucial role in muscle growth and repair.

Improved sexual function: L-Citrulline has been shown to improve erectile dysfunction in men by increasing blood flow to the nether regions.

Dosage Recommendations for L-Citrulline

The recommended dosage of L-Citrulline varies depending on the goals of supplementation. Below are the general dosage recommendations. 

• Exercise performance: A dosage of 6-8 grams of L-Citrulline 60 minutes before exercise. It can be broken up into smaller doses on days you do not exercise.
• Cardiovascular health and erectile dysfunction: Take 2,000 mg of Citrulline, three times a day with meals for a total daily dose of 6,000 mg.

Precautions to Consider When Taking L-Citrulline

L-Citrulline is considered a safe and well-tolerated supplement; however, like most supplements or medication, there are some potential side effects, such as:

• Stomach upset
• Diarrhea
• Nausea

It is best to consult a healthcare professional before taking sports, vitamins, or mineral supplements, especially when pregnant, breastfeeding, or living with a pre-existing medical condition.

Summary

Overall, L-Citrulline is a promising supplement that may have several performance benefits. However, more research is needed to fully understand its potential health benefits and determine the optimal dosage and duration of supplementation.

As with any supplement, it is important to talk to your doctor before taking L-Citrulline if you have any medical conditions or are taking any medications.

References

• Allerton, T., Proctor, D., Stephens, J., Dugas, T., Spielmann, G., & Irving, B. (2018). L-citrulline supplementation: Impact on cardiometabolic health. Nutrients, 10(7), 921. https://doi.org/10.3390/nu10070921

• Examine.com. (2023, February 1). Citrulline health benefits, dosage, safety, side-effects, and more: Supplements. Examine. Retrieved April 6, 2023, from https://examine.com/supplements/citrulline/#examine-database

Authors: 
Teigen Faux, Exercise Physiologist (Honours)

Reviewed:
Stephen Brumwell, Nutritionist (ANTA #40048) for Scientific Accuracy