Investigating L-Citrulline's effects on brain vascular function

Effect of Oral L-Citrulline on the Peripheral and Central Endothelial Function in Young and Older Adults

Phase 1 Interventional University of Oklahoma · NCT05722860

This study is testing if taking L-Citrulline can improve blood flow and brain health in younger adults and older adults.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment30 (estimated)
Ages18 Years to 90 Years
SexAll
SponsorUniversity of Oklahoma Academic / other
Locations1 site (Oklahoma City, Oklahoma)
Trial IDNCT05722860 on ClinicalTrials.gov

What this trial studies

This study examines the impact of L-Citrulline on endothelial function, particularly focusing on brain vascular health in individuals aged 21-45 and those 55-90. It aims to explore how L-Citrulline, an amino acid that can enhance nitric oxide production, may improve blood flow and vascular function in the brain. Participants will receive L-Citrulline in capsule form, and the study will assess its effects on vascular health, which is often compromised with aging. The research seeks to fill a gap in understanding the relationship between L-Citrulline and brain vascular function, an area that has not been extensively studied.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy adults aged 21-45 or 55-90 with no significant central nervous system diseases.

Not a fit: Patients with active CNS diseases, major psychiatric disorders, or those currently using other Citrulline enhancers may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to new insights into improving brain vascular health and function in aging populations.

How similar studies have performed: While L-Citrulline has been studied for its effects on muscle and endothelial function, its specific impact on brain vascular function remains largely untested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age 21-45 and ≥55-90 years of age
* Adequate hearing and visual acuity to participate in the examinations
* Ability to read and write in English
* Competence to provide informed consent

Exclusion Criteria:

* Active CNS disease including multiple sclerosis, uncontrolled seizures, active brain cancer
* Cerebrovascular accident other than TIA within 60 days prior to Visit 0
* Major psychiatric disease, including major depression not currently controlled on medications, alcohol or drug abuse
* Treatment with other Citrulline enhancers (L-Arginine, L-Citrulline Malate) within 4 weeks prior to Visit 0
* Any other medical condition which, in the opinion of investigator, would render the patient inappropriate or too unstable to complete the study protocol

Where this trial is running

Oklahoma City, Oklahoma

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions AgingL-Citrulline
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.