New male pill aims to stop sperm production
NCT ID NCT03455075
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested whether a daily oral pill can safely and temporarily lower sperm counts in healthy men to prevent pregnancy. Ninety-two men took either the experimental drug (DMAU) alone, DMAU plus another hormone (LNG), or a placebo for 12 weeks. The goal was to see if sperm concentration could drop below 3 million per milliliter, a level considered effective for contraception.
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Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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92 people
The number who actually took part.
- Started
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Apr 2018
- Finished
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Mar 2020
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 50 years
- Sex
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Male participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Men who meet all the following criteria are eligible for enrollment in the trial: 1. Male volunteers in good health as confirmed by physical examination, medical history, and clinical laboratory tests of blood and urine at the time of screening. 2. 18 to 50 years of age (inclusive) at the time of the screening visit. 3. BMI ≤36 calculated as weight in kg/ (height in m2). 4. No history of steroid hormone use in the three months prior to the first screening visit or any current medication use which might interfere with steroid metabolism. 5. Subject agrees to use a recognized effective method of contraception with any female partner (refer to Appendix 7 for acceptable forms of contraception) during the course of the study treatment and recovery phases until recovery is confirmed and study exit occurs. 6. Subjects will refrain from donating blood or plasma during the study period and from participating in other investigational drug studies. 7. Subjects will be advised to refrain from excessive alcoholic consumption during the study period. (No more than 15 drinks per week and no alcohol consumption within 24 hours of a study visit.) 8. Subjects will be advised to refrain from excessive marijuana consumption during the study period. (No more than 3 uses per week and no consumption within 24 hours of a study visit.) 9. No known or suspected current alcohol dependence syndrome, chronic marijuana use, or any illicit drug use that may affect metabolism/transformation of steroid hormones and study treatment compliance. 10. Subjects will be advised to refrain/abstain from grapefruit juice during the study period. 11. In the opinion of the investigator, subject is able to comply with the protocol, understand and sign an informed consent and HIPAA form. 12. Subjects will be advised to refrain from major changes in their level of exercise during the study period. Men who meet any of the following criteria are NOT eligible for enrollment in the trial: 1. Men participating in another clinical trial involving an investigational drug within the 30 days prior to the first screening visit. 2. Men not living in the catchment area of the clinic or within a reasonable distance from the study site. 3. Clinically significant abnormal physical or laboratory findings at screening. 4. Elevated PSA (levels ≥ 2.5 ng/mL) at screening, according to local laboratory normal values. 5. IPSS score ≥ 10. 6. Abnormal serum chemistry values at screening, according to local laboratory reference ranges that indicate liver or kidney dysfunction or that may be considered clinically significant. In addition, the following upper limits will be observed: fasting bilirubin less than 2 mg/dL, cholesterol less than 221 mg/dL, and fasting triglycerides less than 201 mg/dL. 7. Abnormal semen analyses or abnormal semen concentration as defined by the WHO semen manual (\< 15 million/mL). 8. Use of androgens within 3 months before first screening visit except for long acting testosterone which requires a wash out period of 4 months prior to screening. 9. Ongoing use of androgens or other compounds for body building including nutritional supplements. 10. Systolic BP ≥130 mm Hg and Diastolic blood pressure BP ≥ 80 and mm Hg; Blood pressure (BP) will be taken 3 times at 5 - minute intervals and the mean of second and third measurements will be used to determine eligibility. (Note: Diagnosis of hypertension or treatment of hypertension is exclusionary.) 11. PHQ-9 score of 15 or above. 12. History of hypertension, including hypertension controlled with treatment. 13. Known history of primary testicular disease or disorders of the hypothalamic-pituitary axis. 14. Benign or malignant liver tumors; active liver disease. 15. History of breast carcinoma. 16. Known history of androgen deficiency due to hypothalamic-pituitary or testicular disease. 17. Known history of cardiovascular, renal, hepatic or prostatic disease or significant psychiatric illness. 18. Positive serology for active Hepatitis (not immunization-related serology) or HIV at screening visit. 19. A serious systemic disease such as diabetes mellitus. 20. History of known, untreated sleep apnea. 21. Partner is known to be pregnant. 22. Men desiring fertility within 12 months of signing consent for study participation. 23. Men participating in competitive sports where drug screening for prohibited substances (including anabolic steroids) is routine. Exclusion is due to the potential of testing positive for androgens that may occur from their study participation coupled with the unknown efficacy (i.e. duration of positive testing) from 12-week daily use of DMAU. 24. Use of sex steroids or medications which might interfere with steroid metabolism (i.e. ketoconazole, finasteride, oral corticosteroids, dutasteride and statins). 25. Use of medications that will interfere or interact with DMAU or LNG. 26. Known hypersensitivity to any of the active substances of DMAU, of the excipients of the study treatment, or LNG.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center
Torrance, California, 90509, United States
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University of Washington Medical Center & Health Sciences
Seattle, Washington, 98195, United States
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