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Study Overview

L-citrulline is a naturally occurring amino acid commonly promoted for maintaining healthy circulation, nitric oxide production, support of cardiovascular health and improved exercise performance. Researchers have increasingly focused on whether L-citrulline supplementation may help support healthy blood pressure and vascular function.^†

A recent double-blind, randomized, placebo-controlled clinical trial published in the journal Nutrition Research examined the vascular effects of low dose L-citrulline supplementation (3,000mg daily) in healthy adults. The findings suggested that the benefits of L-citrulline were most noticeable in participants whose blood pressure fell within the prehypertensive range.^†

What Is L-Citrulline?

L-citrulline is an amino acid naturally found in foods such as watermelon and produced in the body. Once consumed, it is converted into L-arginine, which then increases nitric oxide production.

Nitric oxide plays an important role in supporting cardiovascular health because it helps blood vessels relax and widen. This process, known as vasodilation, improves blood flow and may help reduce vascular resistance and help support healthy blood pressure.^†

Compared with direct L-arginine supplementation, L-citrulline is often considered more effective at raising blood arginine levels because it bypasses significant breakdown in the digestive system.

Main Findings

L-Citrulline Showed the Greatest Benefits in Prehypertensive Adults^†

The most important finding was that vascular improvements were largely influenced by baseline blood pressure status.^†

Participants with prehypertensive blood pressure levels experienced more meaningful vascular benefits compared with individuals whose blood pressure was already within a normal range.^†

Improvements in Vascular Function

Researchers observed improvements in markers associated with vascular health and blood vessel flexibility.

Enhanced nitric oxide production likely contributed to better endothelial function and improved vasodilation.

Blood Pressure Effects

The study found that blood pressure-related improvements were more noticeable in participants with higher baseline readings.^†

This is important because prehypertension is often considered an early warning stage before full hypertension develops.^†

Why Nitric Oxide Matters for Cardiovascular Health

Nitric oxide is one of the body’s most important signaling molecules for vascular function.

Low nitric oxide availability has been associated with:
• Endothelial dysfunction
• Increased arterial stiffness
• Poor circulation
• Elevated blood pressure
• Higher cardiovascular disease risk

Clinical Significance of the Findings

The results suggest that L-citrulline may offer targeted vascular support for adults with borderline elevated blood pressure.^†

Importantly, the benefits appeared less dramatic in participants whose vascular function and blood pressure were already healthy.

Potential Benefits of L-Citrulline Supplementation

Based on current research, possible benefits of L-citrulline may include:
• Improved nitric oxide production^†
• Better endothelial function^†
• Maintain healthy circulation^†
• Reduced arterial stiffness^†
• Helps support healthy blood pressure^†
• Improved exercise blood flow^†
• Supports cardiovascular health^†

Final Takeaway

This clinical study suggests that L-citrulline supplementation may help improve vascular health and helps support healthy blood pressure regulation, particularly in adults with prehypertensive blood pressure levels.^†

The benefits were largely linked to improved nitric oxide availability and endothelial function, both of which play essential roles in cardiovascular health.^†

While L-citrulline is not a replacement for medical treatment, the research supports its potential role as a supportive nutritional strategy for individuals looking to maintain healthy circulation and early cardiovascular function.^†

REFERENCE:
Vascular effects of L-citrulline supplementation in healthy adults are largely influenced by the prehypertensive range of blood pressure: A double-blind, randomized, placebo-controlled, parallel-group study.
Nutrition Research, June, 2026
Dai Nogimura et al.

†These statements have not been evaluated by the Food and Drug Administration.
   This product is not intended to diagnose, treat, cure or prevent any disease.