Low-intensity extracorporeal shock wave therapy (Li-ESWT) has shown promise as a novel treatment for erectile dysfunction (ED), though the the mechanism of action and optimal protocol for administration has not been well-established. The aim of this study is to assess for subjective and objective improvements in erectile function following treatment with Li-ESWT.

Eligible patients will be enrolled as outlined below. Prior to initiation of Li-ESWT treatments, patients will complete validated questionnaires to assess erectile function. In addition, patients will undergo induction of artificial erection in clinic with assessment of penile blood flow using penile Doppler. Intracavernosal pressure measurements will be obtained. A corporal aspirate will be drawn and examined for levels of neuronal nitric oxide synthase, endothelial nitric oxide synthase, brain-derived neurotropic factor and vascular endothelial growth factor. Patients will then receive twice-weekly Li-ESWT treatments of 0.2mJ/mm^2 over 3 treatment sites along the dorsal penile shaft, 1500 shocks per treatment (500 shocks per treatment site), for a total of 3000 shocks per week, for 6 weeks of treatment (totally 18,000 shocks). Following Li-ESWT treatments, patients will complete the same validated questionnaires, penile Doppler studies, corporal aspirates and measurement of intracavernosal pressures immediately following the final Li-ESWT treatment, 4-6 weeks following completion of treatment, and again at 3 and 6 months following completion of treatment.

Inclusion Criteria:

• Male veterans between 40 and 80 years of age
• Known or suspected vasculogenic erectile dysfunction based on clinical history
• In an active sexual relationship with a minimum of 2 sexual attempts per month for at least one month prior to enrollment
• Suffering from ED for at least 6 months
• International Index of Erectile Function - EF domain score between 17-25, Erection Hardness Score score ≥ 1
• Testosterone level between 300-1000ng/dL within one month prior to enrollment
• Hgb A1c ≤ 8% within one month prior to enrollment
• Able to consent to study participation

Exclusion Criteria:

• Erectile dysfunction due to radical prostatectomy, prior pelvic surgery, or radiation therapy to the pelvis within 12 months prior to enrollment.
• Men with known neurogenic or psychogenic ED
• Anatomic malformations of the penis including Peyronie's disease
• Testosterone < 300ng/dL or >1000ng/dL
• Hgb A1c > 8%
• International Normalized Ratio > 2.5, and men on any blood thinners other than 81mg aspirin

Participants will be required to discontinue all erectogenic medications for 1 months prior to initiation of treatment and will not be permitted to use erectogenic medications for the duration of the treatment study.

Participants must be men with erectile disfunction.