Although L-arginine supplementation has long been known to dilate blood vessels and lower blood pressure, a new study shows that a certain amino acid pairing can improve its effectivenesa. Scientific research reveals that when you take L-citrulline together with L-arginine, it has a better absorption rate.
“Our data show for the first time that oral L-citrulline supplementation raises plasma L-arginine concentration and augments nitric-oxide metabolism-dependent signaling in a dose-dependent manner,” the researchers concluded.
In other words, when used in combination, the two amino acid supplements can help lower blood pressure.
The study examined 20 healthy, non-obese subjects including 13 males and seven females. “Diabetes, obesity, hypertension, cardiovascular disease, liver or kidney disease, current infections and smoking were exclusion criteria,” the authors reported. “None of the volunteers received any drugs that might alter amino acid or vitamin status, and dietary habits were kept constant during the study.”
The study was double-blind, randomized, and placebo-controlled – which is considered the gold standard practice in medical research. Subjects were given either L-citrulline .75 grams twice daily, L-citrulline 1.5 grams twice daily, L-citrulline 3 g twice daily, L-arginine immediate release 1.0 g, L-arginine sustained-release 1.6 grams twice daily or placebo for seven days.
“Oral supplementation with L-arginine has been used in a variety of clinical conditions, including (high cholesterol), coronary artery disease, congestive heart failure, peripheral artery disease, sickle cell disease, and in elderly humans, in attempts to improve nitric-oxide mediated vascular function,” according to the researchers.
“A recent small clinical study has suggested that oral L-citrulline may actually lead to higher elevations of plasma L-arginine concentrations than administrations of L-arginine itself,” they added.
Investigators independent of the study performed ultrasound and image analysis, in observer-blinded fashion, to measure the dilation of the arteries.