Evidence explainerCitrulline (L-citrulline and citrulline malate)

Citrulline for the Gym: About 3 Extra Reps, Less Next-Day Soreness, No Endurance Edge

Citrulline is sold for "pump" and performance. Pooled trials find small effects on strength-set reps and next-day soreness, and none on endurance.

By Kymata Health editorial teamPublished October 9, 2026Last reviewed October 9, 2026

Medical review pending. Written by our editorial team from the studies cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • Across 8 studies, 6 to 8 g of citrulline malate before training added about 3 repetitions (6.4%) to strength sets, a small effect [2].
  • A meta-analysis of 4 trials in resistance-trained adults found no effect on maximal strength [3].
  • Across 9 studies, citrulline did not improve time to exhaustion or time trials [4].
  • Across 13 studies, citrulline lowered perceived exertion and muscle soreness 24 hours after exercise, but not at 72 hours [5].
  • Citrulline may raise nitric oxide markers, but that has not been directly linked to better performance [1].

Safety at a glance

From our Citrulline (L-citrulline and citrulline malate) monograph. Published interactions and cautions only, each with its source.

Who should be careful

  • Long-term use. Studies have not adequately assessed the safety of citrulline, particularly when taken as a supplement for months at a time (ODS).[1]
  • Stomach upset. In one trial, 6 of 41 men reported stomach discomfort after 8 g of citrulline malate.[8][1]
  • Before you start. Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[1]

Full Citrulline (L-citrulline and citrulline malate) safety section

The evidence, graded

Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.

  • Grade CImprovedRepetitions to failure in strength trainingCitrulline (L-citrulline and citrulline malate) · Meta-analysis · n=137 · 2021 · PMID 34010809Citrulline malate increased total repetitions by about 3 (6.4%) versus placebo, a small effect (SMD 0.196). Lower-body results showed a tendency for an effect; upper-body results were not significant.
  • Grade CNo effectEndurance: time to exhaustion and time to completionCitrulline (L-citrulline and citrulline malate) · Meta-analysis · n=158 · 2023 · PMID 37155582No significant difference from control in time to exhaustion (SMD 0.03) or time to completion (SMD -0.07).
  • Grade CWorsenedPerceived exertion and muscle soreness after exerciseCitrulline (L-citrulline and citrulline malate) · Meta-analysis · n=206 · 2020 · PMID 33308806Citrulline lowered perceived exertion and muscle soreness at 24 hours after exercise, but not soreness at 72 hours or blood lactate.
  • Grade CImprovedOverall exercise performance (citrulline malate)Citrulline (L-citrulline and citrulline malate) · Meta-analysis · n=644 · 2026 · PMID 42356270Citrulline malate was linked to a small overall improvement in exercise performance (g = 0.16), with wide prediction intervals and limited statistical power. Perceived exertion did not change significantly. GRADE certainty was low to very low.

The nitric oxide idea

About 80% of the body's citrulline is converted in the kidneys into arginine, which the body uses to make nitric oxide, a dilator of blood vessels [1]. That is the "pump" theory. ODS notes citrulline might raise nitric oxide markers, but that response has not been directly related to better athletic performance [1].

Watermelon is the best-known food source: 1 cup of diced seedless watermelon has about 365 mg [1]. Supplement doses in trials were far higher.

Reps: small, mostly upper body

A 2021 meta-analysis of 8 double-blind trials (137 participants, mostly strength-trained men) found that 6 to 8 g of citrulline malate taken 40 to 60 minutes before exercise added about 3 repetitions in total (6.4%) versus placebo [2]. Upper-body results alone were not significant, and lower-body results showed only a tendency [2].

Maximal strength is a different story: a meta-analysis of 4 trials in resistance-trained adults found no effect [3].

Endurance: no benefit

A 2023 meta-analysis of 9 studies in young healthy adults found no difference from control in time to exhaustion or time to completion [4]. ODS describes one small trial in which people taking L-citrulline did worse than placebo on a treadmill test to exhaustion [1].

Soreness and effort

A 2020 meta-analysis of 13 studies found citrulline lowered perceived exertion and muscle soreness 24 hours after exercise, but not soreness at 72 hours or blood lactate [5]. A later 2026 analysis did not find a significant effect on perceived exertion, so even this signal is not settled [6].

How to read the evidence

ODS concludes that the research does not provide strong support for citrulline or citrulline malate to enhance exercise performance [1]. The most consistent signal is a few extra reps in high-rep strength sets. Studies were short, from 1 to 16 days in the ODS review, and long-term safety has not been adequately studied [1].

Choosing between forms is covered in citrulline malate vs L-citrulline. For a supplement with stronger strength data, compare beta-alanine vs creatine.

Quick answers

When should you take citrulline before a workout?

The rep trials gave 6 to 8 g of citrulline malate 40 to 60 minutes before exercise [2].

Does citrulline give a better pump?

It may raise nitric oxide markers, but ODS notes that has not been directly linked to better performance, and our sources do not measure "pump" itself [1].

Does citrulline help with soreness?

Pooled trials found less soreness at 24 hours but not at 72 hours [5].

Keep reading

Full monographs

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References

  1. [1]Dietary Supplements for Exercise and Athletic Performance: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2024.
  2. [2]Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis. Int J Sport Nutr Exerc Metab, 2021. PMID 34010809
  3. [3]Effects of Citrulline Malate Supplementation on Muscle Strength in Resistance-Trained Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Diet Suppl, 2022. PMID 34176406
  4. [4]Effects of citrulline on endurance performance in young healthy adults: a systematic review and meta-analysis. J Int Soc Sports Nutr, 2023. PMID 37155582
  5. [5]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. PMID 33308806
  6. [6]Effects of Citrulline Malate Supplementation on Exercise Performance: A Systematic Review and Three-Level Meta-Analysis. Nutrients, 2026. PMID 42356270

Citrulline (L-citrulline and citrulline malate) and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.

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