Big effect
A meta-analysis found L-citrulline plus L-arginine slashed systolic blood pressure by 10.4 mmHg — but the finding comes from only 415 people in a specific elderly population.
This is an unusually large drop for a supplement combo, but the evidence pool is thin: only three studies synthesized, mostly showing moderate effects, and the result may not apply to younger or healthier adults.
A systematic review of trials in middle-aged and older adults found that taking L-citrulline and L-arginine together lowered systolic blood pressure by about 10 mmHg, with the combination outperforming either supplement alone. The effect is striking, but the meta-analysis included just 415 participants total, and the overall strength of the evidence for L-arginine's blood-pressure benefit is rated low.
Where this fits in the evidence
Pillser has synthesized 4 studies on L-Arginine for Reduced Systolic Blood Pressure — overall evidence strength: Low.
Across 4 studies, 2 reported beneficial effects of L-arginine on reducing systolic blood pressure, while 2 found neutral results. The beneficial effects ranged from small to large, with a moderate effect observed in one meta-analysis (SBP reduction of -5.64 mmHg) among pregnant women. The most-studied populations were pregnant women and older adults, but doses and forms were poorly reported, limiting convergence on an effective dose range.
The study
- Meta-Analysis
- n = 415
- 2025-10
- Clinical nutrition ESPEN
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.