Quick Summary
Does L-citrulline work?
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What is L-citrulline?
L-citrulline (or citrulline) is a non-essential amino acid that the body can convert to L-arginine, which is necessary for the body's production of nitric oxide, a compound that relaxes blood vessels and allows more blood to flow through arteries. (See What It Is)
- Despite much hype, clinical studies of L-citrulline for exercise performance and cardiovascular uses have shown only modest to no benefit. Only one small study suggests that L-citrulline benefits men with mild erectile dysfunction. Studies on benefits for brain function, such as after stroke, have been limited to those in mice. (See What It Does)

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Which is the best L-citrulline supplement?
Among products shown to be accurately labeled in our tests (one product was not) and that passed our tests for heavy metals such as lead (see What CL Found and How Products Were Evaluated), we selected Top Picks for L-citrulline as a powder and as a pill, both of which provide L-citrulline at relatively low cost.
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Is L-citrulline malate a better form?
Both L-citrulline and L-citrulline malate can raise levels of L-citrulline in the body, but there are several reasons why we prefer the L-citrulline form. (See What to Consider When Buying)
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L-citrulline safety and side effects:
L-citrulline supplementation appears to be generally safe and well tolerated in healthy individuals, although occasionally, gastrointestinal upset and heartburn have been reported, and it should be used with caution by people on medication that lowers blood pressure. (See Concerns and Cautions)
Products tested in 2023 and 2024
+— 24 sources
In addition the results of its expert testing, ConsumerLab uses only high-quality, evidence based, information sources. These sources include peer-reviewed studies and information from agencies such as the FDA and USDA, and the National Academy of Medicine. On evolving topics, studies from pre-print journals may be sourced. All of our content is reviewed by medical doctors and doctoral-level experts in pharmacology, toxicology, and chemistry. We continually update and medically review our information to keep our content trustworthy, accurate, and reliable. The following sources are referenced in this article:
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- Balderas-Munoz, Cardiol J 2012
- Barkhidarian, Avicenna J Phytomed 2019
- Boroujeny, Eur J Appl Physiol 2026
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- Chappell, J Int Soc Sports Nutr 2018
- Cormio, Urology 2011
- Farney, J Strength Cond Res 2017
- Goni, Am J Clin Nutr 2022
- Jegatheesan, Clin Nutr 2016
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- Ramos-Hernandez, Clin Nutr ESPEN 2026
- Tovar-Villegas, Gastroenterol Insights 2024
- Yabuki, Brain Res 2013
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- Chappell, J Int Soc Sport Nutr 2018
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- Martin-Olmedo, Int J Sport Nutr Exerc Metab 2024
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- Berry, J Pediatr 2001
- Kashani, J Cardiol 2014
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