The Study
L-Citrulline Supplementation Improves Arterial Blood Flow and Muscle Oxygenation during Handgrip Exercise in Hypertensive Postmenopausal Women
This study is like a fair test where half the women took a supplement and half took a sugar pill, and then scientists checked how well their arms worked during exercise. They found the supplement group did better—but only in this small group of older women with high blood pressure. We can't say it will work for everyone, just that it helped these women in this one test.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if taking a daily amino acid called citrulline helps women with high blood pressure get more blood and oxygen to their arms when they squeeze a handgrip device.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 566 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — better blood flow and oxygen delivery means less fatigue and potentially safer, more effective exercise for women with high blood pressure.
- 2After 4 weeks, citrulline improved blood flow by 48 mL/min, lowered blood pressure by 4 mmHg, increased muscle oxygen by 1.61%, and reduced muscle oxygen strain by 2.76 μM.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2024
Authors
Yejin Kang, Katherine N. Dillon, Mauricio A. Martinez, A. Maharaj, Stephen M. Fischer, Arturo Figueroa
Related Content
Claims (6)
Taking 10 grams of L-citrulline daily for four weeks leads to a measurable improvement in blood vessel function and a small reduction in blood pressure in women with high blood pressure who have gone through menopause.
Taking 10 grams of L-citrulline daily for four weeks increases blood flow and vessel dilation in the forearms of hypertensive postmenopausal women during handgrip exercise.
Taking 10 grams of L-citrulline daily for four weeks leads to a small increase in oxygen levels and a decrease in deoxygenated hemoglobin in the forearm muscles of hypertensive postmenopausal women during handgrip exercise, suggesting changes in how oxygen is delivered and used in that tissue.
In hypertensive postmenopausal women, increases in blood flow to the forearm during hand exercise after taking L-citrulline are linked to improved dilation of the brachial artery, suggesting that the lining of blood vessels plays a role in how blood flow responds to exercise.
Taking 10 grams of L-citrulline daily for four weeks lowers aortic systolic blood pressure by 4 mmHg in postmenopausal women with hypertension, without altering aortic stiffness, suggesting a direct effect on blood vessel tone.
Taking citrulline supplements may help improve blood flow and allow more repetitions during high-repetition, short-rest workouts, but it does not cause measurable increases in muscle size over time.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.