L-Arginine is the direct precursor to nitric oxide, but 60% is destroyed in the gut and liver before reaching the blood. L-Citrulline bypasses this, converts to arginine in the kidneys and produces a larger, longer plasma arginine rise at the same dose.
A 2011 trial in men with mild erectile difficulty found 1.5g citrulline daily improved erection hardness scores in 50% of participants versus 8% on placebo.
L-Citrulline is the first ingredient in our proprietary blend. Per-ingredient dose is not disclosed, so we cannot claim the trial dose.