The goal of this clinical trial is to learn if the drug LIB-01 works to treat erectile dysfunction in male adults. It will also learn about the safety of the drug LIB-01. The main questions it aims to answer are:

• Does the drug LIB-01 improve erectile function in males with erectile dysfunction?
• What medical problems do participants have when taking the drug LIB-01? Researchers will compare the drug LIB-01 to a placebo (a look-alike substance that contains no drug) to see if the drug LIB-01 works to treat erectile dysfunction.

Participants will:

• Take the drug LIB-01 or a placebo every day for 3 days
• Visit the clinic every week for 4 weeks, and at 8 weeks, for checkups and tests

Inclusion Criteria:

1. Provision of signed and dated written informed consent prior to any trial specific procedures.
2. Male participant aged 25 to 65 years, inclusive, at the screening visit.
3. In a stable heterosexual relationship for at least 6 months prior to the screening visit.
4. Total score of 11-25 on questions 1-5 and 15 on the EF domain of the IIEF questionnaire.
5. Highly motivated to obtain treatment for ED.
6. Willing to abstain from unprotected sex and use condom to prevent drug exposure of a partner and pregnancy from first dose until the end-of-trial. In addition, refrain from donating sperm from the date of dosing until 3 months after (last) dosing with the IMP. Any female partner of child-bearing potential of a non-vasectomised trial participant must use contraceptive methods with a failure rate of < 1% to prevent pregnancy until the end-of-trial visit.
7. Understands the trial requirements.

Exclusion Criteria:

1. History of any clinically significant disease or disorder, including psychiatric disorder, which, in the opinion of the Investigator, may either put the participant at risk because of participation in the trial, or influence the results or the participant's ability to participate in the trial.
2. Type 1 diabetes.
3. Haemoglobin A1c (HbA1c) ≥48 mmol/L (6.5%).
4. Any clinically significant illness, medical/surgical procedure or trauma within 4 weeks of the first administration of IMP.
5. Malignancy within the past 5 years, with the exception of in situ removal of basal cell carcinoma.
6. Any planned major surgery within the duration of the trial.
7. History of severe allergy/hypersensitivity or ongoing allergy/hypersensitivity, as judged by the Investigator, or history of hypersensitivity to drugs with a similar chemical structure or class to LIB-01 API.
8. History of priapism, or increased risk due to underlying illness, including but not limited to hemoglobinopathies such as sickle cell anaemia or thalassemia.
9. History of glaucoma.
10. History of Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION).
11. History of prostatectomy.
12. History of alcohol abuse or excessive intake of alcohol, as judged by the Investigator.
13. Presence or history of drug abuse, as judged by the Investigator.
14. History of, or current use of anabolic steroids, as judged by the Investigator.
15. Bleeding deficiencies or ongoing anticoagulant therapy that would put the participant at risk, as judged by the investigator.
16. Uncontrolled cardiac disease within 6 months of screening, including but not limited to uncontrolled hypertension; unstable angina; myocardial infarction or cerebrovascular accident.
17. Use of nitrate medications within 14 days prior to the screening visit.
18. Use of any drug with narrow therapeutic index or drugs that are sensitive substrates, strong inducers or strong inhibitors to CYP3A4 as well as substrates and inhibitors of OATP1B1 or sensitive to substrates to CYP2B6 in accordance with the list provided (see Section 9.6.2.1).
19. Use of oral, injectable, intra-urethral, or topical pro-erectile drugs or supplements, including but not limited to PDE5-Is or prostaglandin E1, or use of devices for ED treatment, within 14 days prior to screening.
20. Primary hypoactive sexual desire.
21. Presence of penile anatomical abnormalities, such as penile fibrosis or Peyronie's disease, which would cause significantly impaired sexual performance, as judged by the Investigator.
22. Insufficient therapeutic effect when using PDE5-Is.
23. History of, or ongoing antiandrogen treatment.
24. Any positive result at the screening visit for serum hepatitis B surface antigen, hepatitis B and C antibodies and/or human immunodeficiency virus (HIV).
25. Abnormal vital signs, laboratory test value or ECG of clinical significance, as judged by the Investigator.
26. Moderate to severe renal impairment with an eGFR (creatinine) ≤60 mL/min (revised Malmö-Lund equation).
27. Moderate to severe hepatic impairment at the time of the screening visit, as judged by the Investigator.
28. Plasma donation within one month of screening or blood donation (or corresponding blood loss) during the last three months prior to the screening visit.
29. Planned treatment or treatment with another investigational therapy (i.e., small molecule or biologic) within 3 months prior to the screening visit.
30. Involvement in the planning, and/or conduct of the trial.
31. The Investigator considers the participant unlikely to comply with trial procedures, restrictions and requirements.