The objective of this project is to provide evidence that L-Citrulline (L-CIT) supplementation can improve vascular function at rest and in response to exercise in postmenopausal women.

L-CIT is a non-essential amino acid that is a precursor to L-arginine, the substrate used to produce an important vasodilatory molecule called nitric oxide. The purpose of this study is to identify the effects of 6 grams of L-CIT for 4 weeks on vascular function (endothelial function, blood flow, muscle oxygenation, and blood pressure) at rest and in response to different stressors (cold pressor test, isometric and dynamic exercise).

Inclusion Criteria:

• Postmenopausal (absence of menstruation > 1 year) between the ages of 50 - 79 years.
• Sedentary ( < 120 minutes of exercise/week)
• Resting systolic blood pressure < 150 mmHg and diastolic blood pressure < 90 mmHg
• Not participating as a subject in another study for at least 2 months prior to the study and for the duration of the study
• Willingness to abstain from food supplements 1 month prior to the start of the study and throughout the duration of the study

Exclusion Criteria:

• Body mass index ≥ 40
• Currently taking more than one vasoactive drug for blood pressure control
• Cardiometabolic diseases or other chronic diseases
• Taking hormone replacement therapy 3 months prior to the study
• Current or prior use of tobacco products
• More than a moderate intake of alcohol
• Use of medications and/or supplements that may affect outcome variables
• Musculoskeletal disorders that will prevent exercise performance