Citrulline malate
Citrulline malate is a supplement that combines the nonessential amino acid L-citrulline with malate, the ionized form of malic acid. Citrulline can raise circulating arginine and nitric-oxide availability, which may affect blood flow; the added performance value of malate itself is uncertain.
It is commonly included in pre-workout boosters and marketed for a larger pump, more repetitions, and less fatigue. Results vary by study and exercise. A 2026 three-level meta-analysis of 30 randomized trials found a small overall performance effect, but wide prediction intervals and low-to-very-low certainty made the practical effect uncertain. A separate systematic review of muscle strength found no significant improvement in strength. Neither result demonstrates greater long-term hypertrophy.
"Citrulline malate" is not one uniform material. Labels may describe different citrulline-to-malate ratios, and the stated ratio does not always reveal the amount of L-citrulline actually supplied. Research on pure L-citrulline cannot automatically validate a blend containing an unknown amount, while findings from one tested blend do not apply to every pre-workout product. A critical review of the evidence and product chemistry highlights these identification and quality problems.
Reported adverse effects are usually gastrointestinal, such as stomach discomfort, nausea, or diarrhea, but safety data for prolonged use and multi-ingredient combinations are less complete. Because nitric-oxide pathways can influence blood pressure, people with cardiovascular conditions or medicines that affect blood pressure should have the combination reviewed by a clinician or pharmacist. Independent testing is useful for checking identity and contamination, but it does not turn inconsistent evidence into a dependable performance effect.