Citrulline is a pro-erectile agent as it is a precursor for arginine, and arginine is the substrate from which nitric oxide is produced and then can induce cGMP (via the NO/cGMP/VEGF pathway); an increase in cGMP is also the ultimate effect of PDE5 inhibitors such as viagra or icariin from Horny Goat Weed.
In men with erectile dysfunction given 1,500mg citrulline daily (two doses of 750mg) for one month was able to benefit half of the 24 patients assessed (as assessed by ‘very satisfied’ with treatment) while there was merely a 8.3% improvement in placebo. Citrulline appears to have pro-erectile properties through arginine. It is likely more potent than arginine at doing this due to having a greater bodily exposure to arginine, but the preliminary evidence right now does not suggest that it is more potent than the reference drug Viagra.
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