Finasteride and Cutibacterium

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).

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Key information

Conditions

Dihydrotestosterone Cutibacterium Acnes Periprosthetic Joint Infection (PJI)

Age range

18 year–65 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 4

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Finasteride 1 mg

Drug

Patients randomized to the experimental group will receive oral Finasteride 1 mg, taken daily, for two weeks

Placebo Control

Drug

Patients randomized to the placebo group will receive one pill containing no active medicine, taken daily, for two weeks.

Primary outcomes

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).
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.

Study contacts

Contact information is provided by the study sponsor or research team.

Anastasia Whitson

CONTACT

[email protected]

206-755-7847

Sponsors and collaborators

Lead sponsor

University of Washington

Other

Registry information

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Jul 28, 2026
Registry last updated: Jul 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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