Graded against 178,763 supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD
Citrulline
Amino AcidLast updated April 2026
AVELOR SUMMARY
L-Citrulline is an amino acid that converts to L-arginine in the kidneys, raising blood arginine and nitric oxide levels more effectively than arginine supplementation itself (oral arginine undergoes extensive first-pass metabolism).
Our research shows solid evidence for blood pressure reduction, exercise endurance, and erectile function improvement, all via enhanced nitric oxide production.
One of the most pharmacologically predictable supplements available.
EVIDENCE GRADES
Exercise endurance/performancereduced fatigue, improved reps to failure
L-Citrulline is produced as a byproduct of nitric oxide synthesis (arginine → NO + citrulline) and recycled back to arginine in the kidneys via the arginine-citrulline cycle. Supplemental citrulline effectively raises plasma arginine levels by 30-50%, more than oral arginine itself, which is extensively metabolized by arginase in the gut and liver.
Higher arginine availability means more substrate for nitric oxide synthase (eNOS), producing more NO. Nitric oxide is a potent vasodilator, it relaxes blood vessel walls, reducing blood pressure, improving blood flow to muscles (exercise performance) and erectile tissue.
Citrulline malate (citrulline bonded to malic acid) is the most common exercise form. The malate may contribute to aerobic energy production via the TCA cycle, though this is secondary to the NO mechanism.
Independently graded against 178,763 indexed supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: April 2026
Not medical advice. Based on published clinical research and systematic reviews.