This is a device study (while the device has been patented and cleared by the FDA, the indication of the use for Erectile Dysfunction has been yet approve). EXSTACY is a study to collect information on which patients who have trouble getting or keeping an erection rigid enough for sex (sometimes known as Erectile Dysfunction or ED) benefit from light intensity shockwave therapy (LI-SWT). LI-SWT is a form of energy transfer to the penis that has been shown to help some men with ED in studies over the past decade. This study will collect information about patients prior to treatment to determine what predicts a good outcome. The investigators hope that this information will help decide which patients are likely to benefit from LI-SWT and which patients should consider other treatments for ED.

Upon signed informed consent, an eligible patient participant with ED is enrolled in the study. Each patient will be asked to complete a series of questionnaires, blood tests, and a non-invasive assessment of blood vessel function using a device called EndoPAT at the initial Baseline Visit. The patients will receive a series of 6 LI-SWT sessions administered to the penis and perineum (the area between the scrotum and anus). A brief survey to assess for any adverse reactions/events will be asked between treatment sessions and follow-up time points at 3, 6, and 12 months from the date of the initial Baseline Visit. Additionally, patients will complete another set of questionnaires at 3, 6, and 12 months from the date of the initial Baseline Visit.

EndoPAT® (Itamar Medical Inc., Atlanta, GA) is an FDA-cleared device designed for the non-invasive assessment of endothelial function and overall arterial health. EndoPAT has been used in prior studies as a way to understand blood flow in men with ED. EndoPAT testing takes about 15-25 minutes and involves assessment of blood flow in the fingers after release of a blood pressure cuff that is tightly applied around the arm.

The UroGold100™ (Tissue Regeneration Technologies, Kennesaw, Georgia, USA) shockwave device will be used for this study. UroGold100™ is a patented shockwave generator that has been used in clinical practice at numerous centers around the country. A standardized protocol for SWT using this device has been patented as well. The device is cleared by the FDA for activation of connective tissue, improved blood supply, and temporary relief of pain. LI-SWT using the Urogold100™ protocol takes about 15 minutes and involves application of shockwave energy to the shaft of the penis and the perineum (area between scrotum and anus) on both sides.

Inclusion Criteria:

1. Patient is over the age of 18
2. Patient has a natal penis (not a neophallus)
3. Patient has ED (defined as IIEF-EF of 25 or less) and EHS < 2 on at least 50% of sexual encounters
4. Patient understands and is able to articulate necessary study procedures and tests
5. Patient has the mental capacity to provide written and verbal informed consent
6. Patient endorses the ability to comply with study procedures throughout the duration of the study

Exclusion Criteria:

1. Placement of a penile prosthesis (malleable or inflatable type)
2. Have a serious medical condition/illness that makes safety or compliance with study procedures and/or engagement in sexual activity inadvisable in the opinion of the PI
3. Untreated severe psychological disease (e.g., psychosis, bipolar disorder)