Background
Arterial hypertension is one of the most important cardiovascular risk factors, featuring the unsatisfactory efficacy of current therapies. The cardiovascular disease paradigm which assumes a crucial role of the endothelial phenotype in shaping the state of the circulatory system has become increasingly dominant and endothelial dysfunction should be treated as avidly as the diseases of other organs. The most valued current anti-hypertensive therapies exert a positive influence on the endothelium due to their pleiotropic effects, but the search for new effective strategies aimed at improving endothelial function is underway. L-arginine trials are part of this quest. The few L-arginine studies in hypertension have brought inconclusive results. The aim of this study was to evaluate the anti-hypertensive efficacy and safety profile of L- arginine during four weeks of oral supplementation to healthy subjects and patients diagnosed with primary mild hypertension.
Material and Method
The study was completed by 54 participants. Ambulatory blood pressure monitoring (ABPM) was used to allot patients to either a healthy control group (19 subjects) or the hypertensive treatment group (35 patients). Later the patients were randomized to either L-arginine (2 or 4 g three times daily or placebo. All participants underwent physical examination and had all basic lab tests and ABPM performed.
Results
Blood pressure (both systolic and diastolic) by ABPM showed statistically significant lowering after 4 weeks of L-arginine supplementation only in the subgroup of patients treated with 12 g of L-arginine daily, with a stronger hypotensive effect observed during the day.
Conclusions
The present findings demonstrate a strong association between L-arginine supplementation and blood pressure reduction.

Keywords: Prospective Studies, Hypertension - physiopathology, Double-Blind Method, Case-Control Studies, Blood Pressure Monitoring, Ambulatory, Arginine - therapeutic use, Antihypertensive Agents - therapeutic use