Watermelon Seed Powder
Also known as: Watermelon seed powder, Watermelon seed flour, Citrullus lanatus seed powder
Overview
Watermelon seed powder is a nutritional supplement derived from the dried seeds of the Citrullus lanatus plant, commonly known as watermelon. Traditionally used in some cultures as a food source and for medicinal purposes, it is gaining recognition as a functional food ingredient due to its rich nutritional profile. This powder is a significant source of proteins, essential minerals such as potassium and magnesium, and various bioactive compounds. Notably, it contains L-citrulline, an amino acid that serves as a precursor to L-arginine and nitric oxide (NO), both crucial for vascular function. Beyond its amino acid content, watermelon seed powder also provides antioxidants and other beneficial minerals. It is primarily utilized for its potential to support cardiovascular health and kidney function, and as a plant-based protein source. While research on watermelon extracts and L-citrulline is extensive, studies specifically on the powder form are emerging, with evidence often extrapolated from broader watermelon research.
Benefits
Watermelon seed powder offers several evidence-based benefits, primarily related to cardiovascular health. Its most significant effect is the potential to reduce systolic blood pressure (SBP) and improve arterial stiffness, largely attributed to increased nitric oxide (NO) bioavailability. A meta-analysis of 9 randomized controlled trials (RCTs) indicated a significant reduction in SBP, total cholesterol, and LDL cholesterol with watermelon supplementation, although effects on diastolic blood pressure (DBP) were not significant. This benefit is mediated by the L-citrulline content, which is converted to L-arginine, enhancing NO production and promoting vasodilation. Furthermore, preclinical studies suggest that watermelon seed extracts may support renal health by reducing uric acid, creatinine, and urea levels, indicating potential kidney protective and diuretic effects. Secondary benefits include antioxidant and anti-inflammatory properties, and potential improvements in lipid profiles. While some studies suggest benefits in glycemic control, the evidence remains inconclusive. Adults with hypertension or cardiovascular risk factors are most likely to benefit, with effects on arterial stiffness observed acutely within hours, and sustained blood pressure and lipid improvements requiring weeks to months of supplementation.
How it works
Watermelon seed powder exerts its primary effects through the L-citrulline-nitric oxide pathway. Upon ingestion, L-citrulline from the powder is well absorbed and converted to L-arginine in the kidneys. L-arginine then serves as a substrate for endothelial nitric oxide synthase (eNOS), an enzyme that produces nitric oxide (NO) in the vascular endothelium. NO is a potent vasodilator, meaning it relaxes and widens blood vessels, leading to reduced arterial stiffness and lower blood pressure. This mechanism directly impacts the cardiovascular system. Additionally, preclinical studies suggest interaction with the renal system, where watermelon seed extracts may inhibit xanthine oxidase, contributing to diuretic and uric acid-lowering effects. The powder's antioxidant compounds also contribute to its overall beneficial effects by mitigating oxidative stress.
Side effects
Watermelon seed powder is generally considered safe with a low risk of adverse effects based on available human studies. No common side effects (occurring in >5% of users) have been reported in randomized controlled trials. Similarly, uncommon (1-5%) or rare (<1%) side effects are not well documented, and no significant adverse events have been consistently reported in research. However, caution is advised regarding potential drug interactions. Due to its blood pressure-lowering effects, watermelon seed powder may have additive effects when taken concurrently with antihypertensive medications, potentially leading to excessive blood pressure reduction. Individuals who are hypotensive or those taking nitrate medications should also exercise caution. There are no formal contraindications identified, but data is limited for specific populations, including pregnant or lactating women, children, and individuals with severe renal impairment. Therefore, these groups should consult a healthcare professional before use.
Dosage
The optimal dosage for watermelon seed powder is not firmly established, as studies often use watermelon extracts or isolated L-citrulline. However, research on watermelon supplementation that shows vascular benefits typically provides approximately 3-6 grams of L-citrulline daily. The exact dose of watermelon seed powder needed to achieve this L-citrulline intake would depend on its specific L-citrulline content, which can vary. Doses of L-citrulline up to 10 grams per day have appeared safe in clinical trials. For acute effects on arterial stiffness, benefits can be observed within 30-90 minutes post-ingestion. For sustained improvements in blood pressure and lipid profiles, chronic supplementation over several weeks to months is typically required. Watermelon seed powder can be consumed as a flour or extract, and its bioavailability may vary depending on processing. There are no specific cofactors required for its efficacy, and general nutritional adequacy supports its benefits.
FAQs
Is watermelon seed powder effective for blood pressure?
Yes, evidence suggests it can modestly reduce systolic blood pressure, primarily by enhancing nitric oxide production, which promotes vasodilation and improves arterial stiffness.
Can it improve cholesterol?
Some research indicates that watermelon supplementation, including components found in the seeds, may lead to reductions in total and LDL cholesterol levels.
Are there risks of side effects?
Watermelon seed powder is generally considered safe with minimal side effects reported in controlled studies. However, caution is advised if taking blood pressure-lowering medications.
How quickly does it work?
Acute vascular effects, such as improved arterial stiffness, can be observed within hours. However, sustained benefits for blood pressure and cholesterol require consistent use over several weeks to months.
Is seed powder better than juice or extract?
Direct comparisons are limited. Seed powder provides a concentrated source of nutrients, but the bioavailability of specific compounds may differ compared to juice or extracts due to processing and matrix effects.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/37369281/ – This systematic review and meta-analysis of 9 RCTs found that watermelon supplementation significantly reduced systolic blood pressure, total cholesterol, and LDL cholesterol in adults with cardiovascular disease risk factors. It also noted an increase in fasting blood sugar, but no significant effect on diastolic blood pressure, heart rate, or BMI. The study highlights the potential cardiovascular benefits of watermelon, though specific data on seed powder was limited.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9592950/ – This meta-analysis focused on L-citrulline and watermelon consumption, concluding that watermelon significantly increases plasma L-citrulline and L-arginine levels. This supports the activation of the nitric oxide pathway, which is crucial for vascular health. The study provides strong evidence for the bioavailability of L-citrulline from watermelon and its role in NO production.
- https://pubs.rsc.org/en/content/articlehtml/2025/fb/d4fb00335g – This review explores the nutritional and bioactive potential of watermelon seeds, including preclinical data suggesting that watermelon seed extracts can reduce uric acid, creatinine, and urea in hyperuricemic animal models. It also noted inhibition of xanthine oxidase, indicating potential kidney protective and diuretic effects. The review highlights emerging evidence for the therapeutic properties of watermelon seeds, though human RCTs are still needed.
- https://www.mdpi.com/2072-6643/14/24/5199 – This source provides general information about watermelon and its components, including L-citrulline, and its role in cardiovascular health. It supports the understanding that watermelon, including its seed components, can contribute to improved arterial stiffness and blood pressure reduction through nitric oxide bioavailability.
