Finasteride and Cutibacterium

July 23, 2026 updated by: Corey Schiffman, University of Washington

High levels of Testosterone causes high amounts of skin bacteria (Cutibacterium Acnes) which can go into the skin during a shoulder replacement surgery and cause a terrible infection.

The goal of this experiment is to have participants take Finasteride, a medication that blocks testosterone production, for 2 weeks and evaluate the following:

  • Blood levels of testosterone
  • Amount of bacteria on the skin.

Participants will:

  • Be assigned to take Finasteride, or a placebo (a look-alike pill with no active medicine) once daily, for 2 weeks
  • Have a small sample of their blood collected and their skin swabbed with a Q-tip to determine Testosterone levels and bacteria on the skin
  • Blood draw and skin testing will take place before starting Finasteride or the placebo (day 0) and at the end of the experiment (day 14).

Study Overview

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Anastasia Whitson
  • Phone Number: 206-755-7847
  • Email: whitsa@uw.edu

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion We will include the group most impacted by PJI

  • Adult males
  • Age between 18 and 65 Exclusion
  • History of cryptorchidism, hypospadias, or other congenital abnormality of male reproductive tract
  • Female sex
  • Age younger than 18 or older than 65
  • Current use of Finasteride or other 5-alpha reductase inhibitors
  • Current use of hormone replacement medications such as testosterone
  • Recent antibiotic use within 3 months
  • Have had a negative reaction to oral Finasteride before
  • Recent use of acne treatment within 3 months
  • Self-report very sensitive skin
  • Allergic to chlorhexidine or isopropyl alcohol
  • Have open wounds on both shoulders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo group
Patients randomized to the placebo group will receive one pill containing no active medicine, taken daily, for two weeks.
Experimental: Finasteride group
Patients randomized to the experimental group will receive oral Finasteride 1 mg, taken daily, for two weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cutibacterium skin load
Time Frame: Skin load will be assessed at day 0 and at the end of the study on day 14 of treatment or placebo.

Skin load will be determined using bacterial culture of the skin and assigning a value based on the report from the microbiology lab: 0 for "no growth"; 0.1 for "growth of 1 colony only" or for "growth in broth only"; and 1, 2, 3 and 4 for 1+, 2+, 3+ and 4+ growth, respectively.

Mann-Whitney U test will be used to compare the change in the semi-quantitative skin load at baseline and day 14 in the intervention and control group, along with comparison of the percentage of subjects in each group that began with a high baseline skin load (>2) and ended with a low skin load (≤1).

Skin load will be assessed at day 0 and at the end of the study on day 14 of treatment or placebo.
Serum Dihydrotestosterone (DHT) Level
Time Frame: levels will be assessed at baseline and after 14 consecutive days of treatment or placebo.
Participants blood will be collected and processed for serum DHT level by the certified and state-licensed phlebotomists and clinical laboratory technicians at our intuition, which is in the same building as the outpatient clinic.
levels will be assessed at baseline and after 14 consecutive days of treatment or placebo.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Corey Schiffman, MD, University of Washington

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

August 31, 2026

Primary Completion (Estimated)

March 31, 2027

Study Completion (Estimated)

August 31, 2027

Study Registration Dates

First Submitted

July 23, 2026

First Submitted That Met QC Criteria

July 23, 2026

First Posted (Actual)

July 28, 2026

Study Record Updates

Last Update Posted (Actual)

July 28, 2026

Last Update Submitted That Met QC Criteria

July 23, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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