Nonessential amino acid
Citrulline
Moderate evidenceConverted to arginine in the body, and studied for exercise performance.
What it is
Citrulline is made in the gut and converted to arginine in the kidneys. It is named after watermelon (Citrullus), where it was first found.
Food sources
WatermelonCucumberPumpkin
What the research shows
- Oral citrulline raises blood arginine more effectively than arginine itself.
- Studies on performance and muscle soreness show mixed but sometimes positive results.
Read the published research on PubMed →
Food first: most people get what they need from a varied diet with enough total protein. Talk to a provider or registered dietitian before adding a supplement, especially if you take medication or have a health condition.