Citrulline is thought to be a proerectile agent because 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);[1] an increase in cGMP is also the ultimate effect of PDE5 inhibitors such as sildenafil (also known as Viagra) or icariin from horny goat weed.[2]
In men with erectile dysfunction (as assessed by weak erections and erectile hardness score[3]) who were given 1,500 mg of citrulline daily (two doses of 750 mg) for one month, half of the 24 participants reported a benefit (as assessed by “very satisfied” with treatment), whereas there was an 8.3% improvement in the placebo group.[4]
Citrulline appears to have proerectile properties that occur vicariously through arginine. It is likely more potent than arginine due to greater bodily exposure to arginine, but the preliminary evidence does not suggest that it is more potent than the reference drug sildenafil.
References
- ^Komori K, Tsujimura A, Takao T, Matsuoka Y, Miyagawa Y, Takada S, Nonomura N, Okuyama ANitric oxide synthesis leads to vascular endothelial growth factor synthesis via the NO/cyclic guanosine 3',5'-monophosphate (cGMP) pathway in human corpus cavernosal smooth muscle cells.J Sex Med.(2008-Jul)
- ^Xin ZC, Kim EK, Lin CS, Liu WJ, Tian L, Yuan YM, Fu JEffects of icariin on cGMP-specific PDE5 and cAMP-specific PDE4 activities.Asian J Androl.(2003-Mar)
- ^John P Mulhall, Irwin Goldstein, Andrew G Bushmakin, Joseph C Cappelleri, Kyle HvidstenValidation of the erection hardness scoreJ Sex Med.(2007 Nov)
- ^Oral L-Citrulline Supplementation Improves Erection Hardness in Men With Mild Erectile Dysfunction