# Citrulline supplementation in postmenopausal women: a systematic review of vascular, muscular, and metabolic effects

## TL;DR

This review examines how citrulline supplements may help postmenopausal women with blood pressure and vascular health, but results are mixed for other benefits.

## Contribution

The first systematic review evaluating citrulline's effects on vascular, muscular, and metabolic outcomes in postmenopausal women.

## Key findings

- Citrulline may reduce systolic blood pressure by up to 9 mmHg in some postmenopausal women.
- Mixed results for arterial stiffness and endothelial function improvements.
- No consistent metabolic benefits observed from citrulline supplementation.

## Abstract

Postmenopausal women are at increased risk of developing cardiovascular, muscular, and metabolic dysfunction due to hormonal changes associated with aging. Citrulline, a non-essential amino acid and precursor to nitric oxide, has gained interest as a potential dietary supplement for improving vascular health, muscle function, and metabolic parameters in this population.

This systematic review aims to evaluate the effects of citrulline supplementation, administered directly or via watermelon products, on cardiovascular, muscular, and metabolic outcomes in postmenopausal women.

A comprehensive literature search was conducted using PubMed, Web of Science, and Scopus databases to identify randomized controlled trials (RCTs) investigating citrulline supplementation in postmenopausal women. Studies were included if they reported outcomes related to blood pressure, arterial stiffness, endothelial function, muscle strength or mass, metabolic parameters, and safety. Study quality was assessed using the Cochrane Risk of Bias Tool 2. Due to heterogeneity in study designs and reported outcomes, results were synthesized narratively.

Twelve RCTs involving 360 postmenopausal women were included. all conducted in the United States, with study durations ranging from 4 to 8 weeks and participant ages between 50 and 75 years. Seven studies reported blood pressure outcomes, with most showing reductions in systolic blood pressure and mean arterial pressure. Five studies examined arterial stiffness, with mixed findings on pulse wave velocity and augmentation index. Four studies assessed endothelial function, two of which demonstrated significant improvements in flow-mediated dilation. Muscle function outcomes were investigated in two studies, suggesting improvements only when citrulline was combined with resistance training. Six studies assessed metabolic parameters, with no consistent effects observed on body weight, glucose, insulin, or lipid profiles. Across all studies, no adverse effects related to citrulline supplementation were reported.

Citrulline supplementation may offer benefits for blood pressure regulation (up to 9 mmHg SBP reduction in some studies) in hypertensive postmenopausal women, but evidence for arterial stiffness, endothelial function, and metabolic outcomes remains inconsistent. Further large-scale studies are needed before clinical recommendations can be made.

The online version contains supplementary material available at 10.1186/s12905-026-04277-6.