Comparing Sarecycline and Doxycycline Effects on the Skin and Gut Bacteria in Acne.

April 15, 2026 updated by: Integrative Skin Science and Research

The Effects of Sarecycline Versus Doxycycline on the Gut Microbiome and Skin Microbiome in Acne.

This study is being done to help better understand how the gut and skin bacteria of the body change when people with acne are treated with Sarecycline or Doxycycline. The bacteria in the gut and on the skin will be studied to see how each treatment may affect them and whether they change the profile of the bacteria that is present.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

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

Study Locations

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

1) Diagnosis of acne vulgaris with:

  • At least 10 inflammatory lesions (papules, pustules, and nodules) up to 100 noninflammatory lesions (open and closed comedones)
  • No more than 2 nodules on the face

Exclusion Criteria:

  1. Dermatological condition of face or facial hair that could interfere with clinical evaluations
  2. Subjects who have used the following medications (topical refers only to the facial area) will not be eligible:

2a) Within 2 week prior to randomization:

  • Topical acne medications such as retinoids, antibiotics, hormonal modulators
  • Topical benzoyl peroxide

  • Topical anti-inflammatories and corticosteroids

    2b) Within 4 weeks prior to randomization:

  • Systemic antibiotics
  • Systemic acne treatments
  • Oral probiotic supplement

  • Systemic corticosteroids

    2c) Within 12 weeks prior to randomization:

  • Systemic retinoids

    3) Individuals who have changed any of their hormonal based contraception or therapies within 3 months prior to joining the study.

    4) Individuals who are pregnant or breastfeeding.

    5) Individuals on oral contraceptive pills or progesterone or estrogen containing therapies unless they have been on a stable dose for 2 months.

    6) Individuals on finasteride or dutasteride

    7) Current tobacco smoker or a tobacco smoking history that is greater than 5 pack-years.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Sarecycline Group
Half of the participants will be randomized to receive sarecycline treatment.
Drug: Sarecycline
One tablet by mouth (weight based dosing at 1.5 mg/kg and rounded to the closest tablet dose at either 60 mg, 100mg, or 150 mg tablet) once a day with food and a full glass of water (about 8 ounces)
Experimental: Doxycycline Group
Half of the participants will be randomized to receive doxycycline treatment.
Drug: Doxycycline
100 mg twice daily with food and a full glass of water (about 8 ounces)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in the relative abundance of tetracycline-resistant bacteria in the gut microbiome
Time Frame: From enrollment to the end of treatment at 4 weeks.
Assessing change in the relative abundance of tetracycline resistant bacteria in the gut microbiome following treatment.
From enrollment to the end of treatment at 4 weeks.
Change in the relative abundance of fungi/yeast in the gut microbiome
Time Frame: From enrollment to the end of treatment at 4 weeks.
Assessing change in the relative abundance of fungi/yeast in the gut microbiome following treatment.
From enrollment to the end of treatment at 4 weeks.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in inflammatory and non-inflammatory lesions
Time Frame: From enrollment to the end of treatment at 4 weeks.
Assesing change in inflammatory and non-inflammatory lesions.
From enrollment to the end of treatment at 4 weeks.
Change in the diversity of the gut microbiome: Shannon Diversity
Time Frame: From enrollment to the end of treatment at 4 weeks.
Assessing the change in Alpha Diversity of the gut microbiome via Shannon Diversity
From enrollment to the end of treatment at 4 weeks.
Change in investigator global assessment of acne
Time Frame: From enrollment to the end of treatment at 4 weeks.
Change in investigator global assessment of acne
From enrollment to the end of treatment at 4 weeks.
Change in relative abundance of short chain fatty acid production genes
Time Frame: From enrollment to the end of treatment at 4 weeks.
Assessing change in relative abundance of short chain fatty acid production genes upon gut microbiome analysis.
From enrollment to the end of treatment at 4 weeks.
Change in skin microbiome relative abundance
Time Frame: From enrollment to the end of treatment at 8 weeks.
Assessing change in the relative abundance of the skin microbiome via Shannon Diversity.
From enrollment to the end of treatment at 8 weeks.
Change in the skin microbiome relative abundance of fungi/yeast
Time Frame: From enrollement to the end of treatment at 4 weeks.
Assessing change in the relative abundance of fungi/yeast in the skin microbiome.
From enrollement to the end of treatment at 4 weeks.

Collaborators and Investigators

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

Sponsor

Integrative Skin Science and Research

Collaborators

Almirall, S.A.

Investigators

  • Principal Investigator: Raja Sivamani, MD, Integrative Skin Science and Research

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)

April 20, 2026

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

April 15, 2026

First Submitted That Met QC Criteria

April 15, 2026

First Posted (Actual)

April 22, 2026

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 15, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRI26_02_SarecyclinevsDoxy

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

Yes

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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