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Supplement Forms/Alternate Names:

L-citrullineCitrulline malate


Citrulline is an amino acid found in the body. It has been used to improve blood pressure and athletic performance. Citrulline can be taken as a pill or powder.


5 grams 1 to 3 times daily

What Research Shows

Likely Effective

  • High blood pressure —likely to improve blood pressure D1, D2

Not Enough Data to Assess

  • Athletic performance A1
  • Erectile dysfunction (impotence) B1
  • Heart failure C1, C2
  • Obesity E1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take citrulline in small doses for a short time. Not enough studies have been done to say whether it is safe to use for a long period. It is also not known whether it is safe to take by women who are pregnant or breastfeeding.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Athletic Performance

A1. Trexler ET, Persky AM, et al. Acute Effects of Citrulline Supplementation on High-Intensity Strength and Power Performance: A Systematic Review and Meta-Analysis. Sports Med. 2019;49(5):707-718.

B. Erectile Dysfunction

B1. Cormio L, De Siati M, et al. Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology. 2011 Jan;77(1):119-122.

C. Heart Failure

C1. Orozco-Gutiérrez JJ, Castillo-Martínez L, et al. Effect of L-arginine or L-citrulline oral supplementation on blood pressure and right ventricular function in heart failure patients with preserved ejection fraction. Cardiol J. 2010;17(6):612-618.

C2. Balderas-Munoz K, Castillo-Martínez L, et al. Improvement of ventricular function in systolic heart failure patients with oral L-citrulline supplementation. Cardiol J. 2012;19(6):612-617.

D. High Blood Pressure

D1. Mahboobi S, Tsang C, et al. Effect of L-citrulline supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials. J Hum Hypertens. 2019;33(1):10-21.

D2. Barkhidarian B, Khorshidi M, et al. Effects of L-citrulline supplementation on blood pressure: A systematic review and meta-analysis. Aviencanna J Phytomed. 2019;9(1):10-20.

E. Obesity

E1. Figueroa A, Alvarez-Alvarado S, et al. l-Citrulline supplementation attenuates blood pressure, wave reflection and arterial stiffness responses to metaboreflex and cold stress in overweight men. Br J Nutr. 2016 Jul;116(2):279-285.

Last reviewed February 2020 by EBSCO NAT Review Board Eric Hurwitz, DC  Last Updated: 6/17/2020