L-Citrulline

Oral L-Citrulline Supplementation Improves Erection Hardness in Men With Mild Erectile Dysfunction

To test the efficacy and safety of oral L-citrulline supplementation in improving erection hardness in patients with mild erectile dysfunction (ED). L-arginine supplementation improves nitric oxide-mediated vasodilation and endothelial function; however, oral administration has been hampered by extensive presystemic metabolism. In contrast, L-citrulline escapes presystemic metabolism and is converted to L-arginine, thus setting the rationale for oral L-citrulline supplementation as a donor for the L-arginine/nitric oxide pathway of penile erection.

A total of 24 patients, mean age 56.5 ± 9.8 years, were entered and concluded the study without adverse events. The improvement in the erection hardness score from 3 (mild ED) to 4 (normal erectile function) occurred in 2 (8.3%) of the 24 men when taking placebo and 12 (50%) of the 24 men when taking L-citrulline (P < .01).

goldjournal.net/article/S0090-4295(1001661-4/abstract

My opinion - don’t bother. Have taken it and L-arginine and have not seen the benefits. I think you would if it was strictly a bloodflow issue but I believe ours is much more hormonal