Across 4 studies, all reported beneficial effects of L-Citrulline on reducing aortic systolic blood pressure, with moderate to large effect sizes. The most-studied doses were 6 g/day and 10 g/day in clinical populations, with effects observed at a median duration of 28 days.
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Evidence base is small (only 4 studies) — conclusions should be considered preliminary.
reduced aortic systolic BP (Δ3 ± 5 vs. Δ-4 ± 6 mmHg) at rest
aortic SBP (Δ-10 ± 14 vs. Δ4 ± 12 mmHg; P = 0.005) ... responses to the CPT were significantly attenuated following L-CIT supplementation vs. placebo.
Four weeks of L-citrulline supplementation improved... aortic systolic blood pressure... in the fasted state compared to placebo (all p < 0.05). During acute hyperglycemia, CIT supplementation... reduced aortic systolic BP... compared to placebo (all p < 0.05).
CIT attenuated ΔSBP (−9 ± 2 v. −1 ± 1 mmHg, P = 0·006)