TargetedHeart, metabolismVegan form available
L-citrulline
A nitric-oxide precursor that measurably improves vascular function and lowers blood pressure; better absorbed than arginine.
3/5· Multiple human trialsEstimated monthly cost: ≈ 10 €
Dose
3–6 g citrulline (or 6–8 g citrulline malate).
Timing
Morning or an hour before training.
⚠ Cautions
Additive with blood-pressure drugs and PDE5 inhibitors (sildenafil).
What it is
An amino acid from watermelon; converted in the kidney to arginine, the NO source.
What the evidence shows
Meta-analysis (8 RCTs): 3–6 g/day –4 mmHg systolic; improved flow-mediated dilation. Small effect on exercise performance (2019 meta-analysis).
Goals
Heart, blood sugarEnergy, fatigue
Last reviewed: 6 September 2026
This site is educational and does not replace medical advice. Start any supplement or drug only after consulting a doctor or pharmacist.