This study aims to evaluate the clinical efficacy and histological changes of tadalafil combined with low-intensity pulsed ultrasound (LIPUS) in patients with erectile dysfunction (ED) through a randomized controlled trial.

Erectile dysfunction (ED) is defined as the persistent inability to achieve and maintain a sufficient erection for satisfactory sexual performance for more than six months. Low-intensity pulsed ultrasound (LIPUS), a non-invasive therapy, improves the pathological changes in the corpora cavernosa and penile hemodynamics by promoting the regeneration of connective tissue, blood vessels, and cavernous nerves, as well as reducing inflammation.

This study will recruit 114 patients diagnosed with ED and use simple random sampling to allocate them into a treatment group and a control group in a 1:1 ratio. The treatment group will receive daily 5mg tadalafil combined with LIPUS therapy twice a week for 4 weeks, followed by a 4-week interval without LIPUS treatment, and then repeat the treatment. The control group will receive only daily 5mg tadalafil.

Efficacy will be evaluated primarily through the minimal clinically important difference (MCID) of the International Index of Erectile Function-5 (IIEF-5) at each follow-up point, combined with Erectile Hardness Score (EHS), penile blood flow parameters, and elasticity values for comprehensive assessment.

This trial may provide additional clinical evidence for the efficacy, safety, and cost-effectiveness of tadalafil combined with LIPUS in treating ED patients. The inclusion of penile blood flow parameters and two-dimensional shear wave elastography will help establish a comprehensive evaluation system combining ED symptoms with histological assessment, providing new methods for efficacy evaluation.

Inclusion Criteria:

• Age between 21 and 65 years old.
• An International Index of Erectile Function-5 (IIEF-5) score of 21 or less.
• First-time diagnosis of erectile dysfunction (ED) without prior treatment from traditional Chinese or Western medicine.
• A stable heterosexual relationship for at least 3 months.
• Agreement to attempt sexual intercourse at least four times every four weeks during the study period.
• Signing of an informed consent form.

Exclusion Criteria:

• Erectile dysfunction caused by spinal/neural injury or radical prostatectomy.
• History of priapism or penile anatomical abnormalities.
• Use of a penile prosthesis.
• Severe and poorly controlled psychological disorders.
• Untreated endocrine disorders, such as hypogonadism, hypothyroidism, or pituitary dysfunction.
• History of myocardial infarction, stroke, life-threatening arrhythmias, or potential cardiovascular risks during sexual activity within the six months prior to enrollment.
• Inability to complete the participant records required for the trial.
• Allergic constitution and multiple drug allergies.

Separate the person responsible for randomization and assignment from the outcome assessor, ensure that the evaluator does not have access to information for the participant group, and assign a unique code to the participant, and the evaluator is only exposed to the code without knowing the specific intervention behind it.