New male birth control pill could work in minutes
NCT ID NCT07393334
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study tests a new non-hormonal male contraceptive called NLS-133, taken just before sex to reduce sperm count and semen volume. Ten healthy men will receive the drug, an active control, or a placebo in random order. The goal is to see if it safely and effectively lowers sperm count and motility.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- NLS-133 (combination of two FDA-approved drugs)
- What this could lead to
- If it works, this could lead to a new non-hormonal, on-demand male contraceptive pill.
- What could go wrong
- This is a very small early-phase trial with only 10 men, so results may not apply widely. The drug is taken just before sex, so effectiveness and safety are still uncertain.
This is an AI summary of the original study and may miss details. Read our disclaimer.
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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About 10 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Dec 2025
- Expected to finish
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May 2026
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
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 55 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.
Inclusion Criteria: 1. Male, age 18-55. 2. Normal physical examination and testicular volume \>15 cc 3. No significant medical history that would impact the safety of the study. 4. No current use of drugs that comprise NLS-133 5. Normal values on baseline hematology, blood chemistry and liver function tests and serum testosterone. 6. Normal baseline sperm parameters (semen volume \>1.4 cc, sperm concentration \>15 million/ml, motility \>40% and morphology \>4%). 7. Willing and able to comply with all study requirements and procedures. Exclusion Criteria: 1. History or evidence of erectile dysfunction. 2. Inability to produce semen samples in clinic setting. 3. Significant chronic or acute medical illness. 4. Previous or current ethanol or illicit drug abuse. 5. Evidence of significant underlying disease (based on results of the physical exam and the routine labs). 6. Known infertility or hypogonadism. 7. Planned or anticipated use of any prohibited medications during participation in the study. These include use of sex hormones for treatment, testosterone, anabolic steroids, retinoic acid (e.g., Accutane®), vitamin A, other drugs known to inhibit spermatogenesis, opioids, cocaine, methamphetamine, and/or the consumption of \>4 alcoholic beverages daily. 8. Presence of moderate-to-severe pulmonary or cardiovascular disease 9. Known active hepatitis B, hepatitis C, human immunodeficiency virus (HIV), or COVID-19 infection. 10. History of malignancy within 5 years before the Screening Visit, except fully treated and resolved non-metastatic squamous or basal cell carcinoma of the skin. 11. Known active chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antifungals, antiparasitics or antiprotozoals during the Screening period. 12. Any other acute or chronic medical or psychiatric condition or laboratory abnormality that could increase the risk associated with study participation in the judgment of the investigator would make the participant inappropriate for entry into the study. 13. Participation in another investigational clinical trial within the last 30 days. 14. Participants who live in detention on court order or on regulatory action. 15. Related to sponsor or staff involved in the conduct of the study.
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As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Population Center for Research in Human Reproduction and Departments of Medicine, University of Washington
RECRUITINGSeattle, Washington, 98195, United States
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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- Male birth control pill moves closer to reality
- Hydrogel implant could offer reversible male contraception
- New male pill aims to stop sperm production
- Male birth control pill moves closer to reality