 The proposed mechanism of action for LI-ESWT in ED is that it improves endothelial function and triggers angiogenesis through induction of local growth factors and endothelial nitric oxide synthase. The literature generally confirms that LI-ESWT is safe and cohort studies investigating the clinical effects have been encouraging. Meanwhile, randomized trials have shown contradictory results. Thus, a randomized trial in 67 PDE5-I responders showed statistically greater improvements in the Erectile Function Domain of the International Index of Erectile Function IIEF with active LI-ESWT treatment compared to a sham treatment p0.032. 