Topical Lactobacillus reuteri for hair loss due to androgenetic alopecia

Safety and Efficacy of Lactobacillus Reuteri for Androgenetic Alopecia: A Single-Center, Randomized, Double-Blind, Placebo-Controlled Trial

This trial will test whether applying a topical Lactobacillus reuteri solution can increase hair count and improve hair quality in adults (18–60) with androgenetic alopecia over 12 months.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 388 (estimated)
• Ages: 18 Years to 60 Years
• Sex: All
• Sponsor: Shenzhen People's Hospital (Academic / other)
• Locations: 1 site (Shenzhen, Guangdong)
• Trial ID: NCT07370519 on ClinicalTrials.gov

What this trial studies

This is a single-center, randomized, double-blind, placebo-controlled Phase 2 trial comparing four 12-month topical regimens: live Lactobacillus reuteri, inactivated Lactobacillus reuteri, normal saline placebo, and 5% minoxidil. Participants and outcome assessors are blinded to assignment to reduce bias. The primary outcome is change in hair count per square centimeter after one year, with secondary measures of hair thickness and quality. The trial is based on the hypothesis that rebalancing the scalp microbiome may support hair follicle function and slow or reverse hair thinning.

Who should consider this trial

Good fit: Adults aged 18–60 with clinically confirmed androgenetic alopecia (Norwood-Hamilton II–IV or Ludwig I–III), generally healthy, and who have not used hair-loss medications in the prior six months are ideal candidates.

Not a fit: Patients with long-standing or advanced AGA (>5 years progression), alopecia areata, active scalp disease, uncontrolled diabetes or cardiovascular disease, recent hair-loss treatments, or those unable to attend Shenzhen clinic visits may not receive benefit or are excluded.

Why it matters

Potential benefit: If successful, this could offer a new topical, microbiome-based treatment that increases hair count and improves hair quality, potentially with fewer systemic effects than some current options.

How similar studies have performed: Microbiome-targeting approaches for hair loss are largely novel: there is limited preclinical and early clinical evidence suggesting potential benefit but no established proof yet.

Eligibility criteria

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.

Where this trial is running

Shenzhen, Guangdong

• Shenzhen People's Hospital — Shenzhen, Guangdong, China (Recruiting)

Study contacts

• Study coordinator: Jianglin Zhang

Conditions Androgenetic Alopecia; Lactobacillus reuteri