Topical Application of Lactobacillus Reuteri for Androgenetic Alopecia

Southern University of Science and Technology

Status and phase: Not yet enrolling; Phase 2

Conditions: Androgenetic Alopecia (AGA)

Treatments: Biological: Lactobacillus reuteri; Drug: 5% Minoxidil; Biological: Inactivated Lactobacillus reuteri; Drug: Normal Saline

Study type: Interventional

Funder types: Other

Identifiers

NCT07370519

LL-KY-2025109-02

Details and patient eligibility

About

This is a single-center, randomized, double-blind, placebo-controlled clinical trial designed to evaluate whether topical application of Lactobacillus reuteri can safely and effectively treat androgenetic alopecia. The study is based on the concept that balancing the scalp's microbial community may support hair follicle function. Participants will be randomly assigned to one of four groups receiving either active probiotic solution, inactivated probiotic solution (control for non-viable bacterial effects), a saline placebo, or the standard treatment 5% minoxidil solution for 12 months. Neither participants nor assessing clinicians will know the assigned treatment. The main goal is to measure improvement in hair count per square centimeter after one year. Additional measures include changes in hair thickness and quality. This research seeks to provide high-quality scientific evidence on a new microbiome-targeting approach, offering future patients and healthcare providers insights into a potential alternative or complementary treatment strategy for hair loss.

Enrollment: 388 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Patients meeting AGA diagnostic criteria (confirmed by medical history, clinical presentation, and trichoscopy) classified as Norwood-Hamilton stage II-IV or Ludwig grade I-III;
2. Provision of informed consent and voluntary participation;
3. Aged 18-60 years with generally good health status;
4. No use of any hair loss medications within the past six months;
5. Absence of alopecia areata, local infections, or neuromuscular disorders.

Exclusion criteria

1. AGA progression >5 years;
2. Active skin disease (e.g., psoriasis flare) or uncontrolled diabetes/CVD;
3. Investigator-assessed protocol non-feasibility.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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388 participants in 4 patient groups, including a placebo group

Test Group

Experimental group

Description:

Daily application of 1 sachet containing Lactobacillus reuteri powder (≈10\^9 CFU) dissolved in 1 mL normal saline within a brown glass vial. After thorough mixing, 1 mL of the probiotic solution was topically applied to the scalp using cotton swabs following scalp cleansing. Participants refrained from hair washing for ≥6 hours post-application. Applied once daily for 12 months.

Treatment:

Biological: Lactobacillus reuteri

Inactivated Control Group

Other group

Description:

Daily application of 1 sachet containing inactivated Lactobacillus reuteri powder (≈10\^9 CFU pre-inactivation) dissolved in 1 mL normal saline within a brown glass vial. After thorough mixing, 1 mL of the solution was topically applied to the scalp using cotton swabs following scalp cleansing. Participants refrained from hair washing for ≥6 hours post-application. Applied once daily for 12 months.

Treatment:

Biological: Inactivated Lactobacillus reuteri

Positive Control Group

Active Comparator group

Description:

Commercially available 5% minoxidil tincture was aliquoted into brown glass vials (1 mL/vial). Following daily scalp cleansing, 1 mL solution was topically applied to the scalp. Participants refrained from hair washing for ≥6 hours post-application. Applied once daily for 12 months.

Treatment:

Drug: 5% Minoxidil

Negative Control Group

Placebo Comparator group

Description:

Normal saline was aliquoted into brown glass vials (1 mL/vial). Following daily scalp cleansing, 1 mL solution was topically applied to the scalp using cotton swabs. Participants refrained from hair washing for ≥6 hours post-application. Applied once daily for 12 months.

Treatment:

Drug: Normal Saline