The Study
Watermelon Nutritional Composition with a Focus on L-Citrulline and Its Cardioprotective Health Effects—A Narrative Review
This study is like a summary of lots of different experiments where people ate watermelon and had their blood tested. It says watermelon might help your blood vessels because of a chemical inside it, but it doesn't prove it for sure — some studies showed a little help, others showed nothing.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
Watermelon has a special amino acid called L-citrulline that your body turns into L-arginine, which helps make nitric oxide — a molecule that relaxes your blood vessels.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 51 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — for people with high blood pressure or obesity, this could mean less strain on the heart and better blood flow, potentially reducing heart disease risk.
- 2Eating watermelon or its rind (which has more L-citrulline) can raise L-citrulline and L-arginine in the blood.
- 3Studies showed that 2.7–4.0 grams of L-citrulline per day for 6 weeks lowered blood pressure in people with high blood pressure or obesity.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2025
Authors
Diego dos Santos Baião, D. D. da Silva, V. M. F. Paschoalin
Related Content
Claims (6)
Eating foods high in citrulline regularly leads to more stable physiological effects than taking a single dose of citrulline.
In adults with prehypertension or obesity, consuming watermelon or watermelon powder providing 2.7–4.0 grams of L-citrulline daily for six weeks is linked to lower central and peripheral blood pressure and reduced arterial stiffness, though the effect size differs between studies.
Consuming L-citrulline from watermelon raises levels of L-arginine in the blood through kidney conversion, leading to increased nitric oxide production and improved blood vessel function in adults with cardiovascular risk factors.
Eating watermelon pulp or rind raises levels of L-citrulline and L-arginine in the blood, and how much they rise depends on whether the pulp or rind is eaten and the person's vascular health before consumption.
Watermelon rind has more L-citrulline than the pink part of the fruit, with amounts between 60 and 500 milligrams per 100 grams of fresh weight, making it a viable source for extracting L-citrulline.
L-citrulline from watermelon causes no gastrointestinal side effects at doses up to 15 grams per day, while L-arginine supplements do, because L-citrulline is absorbed differently in the intestines and does not pass through the liver first.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.