Pelage Pharmaceuticals: Pioneering Stem Cell Therapy for Hair Loss

Hair loss might seem like a cosmetic concern, but to the scientists at Pelage Pharmaceuticals, it’s a question of regenerative biology. The Los Angeles–based biotech raised $120 million in Series B funding in October 2025 to pursue something long thought impossible: reawakening the dormant stem cells inside hair follicles.

At its core, Pelage’s work is about restoring function to a system that’s gone quiet. Hair follicle stem cells don’t die in androgenetic alopecia—they just stop responding to the biological signals that once triggered growth. Pelage believes those cells can be reactivated, unlocking a regenerative pathway that has remained untapped since the condition was first described.

Addressing an Unmet Medical Need

Androgenetic alopecia affects more than 80 percent of men and about 40 percent of women over their lifetimes. Despite its prevalence, treatment options have barely evolved in decades. The only FDA-approved monotherapies—finasteride and minoxidil—were both developed in the late 20th century and discovered more by chance than by design.

Finasteride works hormonally, blocking the conversion of testosterone to dihydrotestosterone (DHT), a molecule linked to follicle shrinkage. Minoxidil, a vasodilator originally used for hypertension, promotes hair growth through mechanisms that remain only partly understood.

Neither treatment targets the underlying biological machinery of the follicle itself. They slow the loss; they don’t restore the cycle. That gap—between managing symptoms and reactivating the root cause—is where Pelage is placing its bet.

A Stem Cell-Based Approach

Pelage's lead program, PP405, is a first-in-class topical small molecule designed to reactivate dormant hair follicle stem cells through metabolic activation. The therapy promotes lactate production, which acts as a metabolic signal that shifts hair follicle stem cells from a dormant to an active state.

This approach is particularly promising because hair follicle stem cells remain present even in balding areas. Rather than simply slowing hair loss progression, PP405 aims to restart the body's natural ability to grow hair by targeting these dormant stem cells.

The therapy is grounded in over ten years of laboratory research from UCLA into the metabolic activation of hair follicle stem cells.

Phase 2a Clinical Results

In July 2025, Pelage reported positive interim results from a randomized, placebo-controlled Phase 2a trial evaluating PP405 in 78 adult patients with androgenetic alopecia. The study included men and women aged 18 to 55 years, representing diverse skin phototypes and hair textures.

Participants received either 0.05% PP405 topical gel or placebo once daily for four weeks and were followed for up to 12 weeks. The trial met its primary safety endpoint, with PP405 demonstrating excellent tolerability and no systemic absorption detected in blood plasma.

While designed primarily to assess safety, the preliminary efficacy results exceeded expectations. At Week 8—four weeks after completion of dosing—31% of men with moderate to severe hair loss who received PP405 experienced a greater than 20% increase in hair density, compared to 0% in the placebo group. This rapid response is notable, as visible hair regrowth typically requires 6-12 months of continuous therapy with current treatments.

PP405 also induced new hair growth from follicles where no hair was previously present, suggesting the therapy can go beyond slowing hair loss and directly drive hair follicle regeneration.

Following the randomized controlled phase, participants in the placebo group were eligible to enroll in a three-month open-label extension to assess long-term safety, which is now complete. The company plans to present the full dataset at a medical meeting in 2026.

Leadership Team

Pelage’s leadership reflects a rare blend of scientific depth and operational experience—people who’ve spent their careers studying regeneration and now aim to turn that knowledge into a treatment that actually works.

Daniel Gil, Ph.D., Chief Executive Officer, leads the company with a focus on translating stem cell biology into clinically meaningful therapies. His goal isn’t just to prove that hair follicle reactivation is possible—it’s to make it accessible and reliable at scale.

William Lowry, Ph.D., Co-founder and President, is the scientist behind the science. A longtime UCLA professor, Lowry uncovered the metabolic mechanisms that keep hair follicle stem cells dormant and later showed they could be reawakened. His lab’s work forms the scientific backbone of Pelage’s platform.

Christina Weng, M.D., Chief Medical Officer, oversees clinical development and trial design, ensuring that Pelage’s research meets the same standards of rigor expected of any new therapeutic area.

The company’s board includes Cathy Friedman of GV, who serves as Chair, and Richard Heyman, Ph.D., of ARCH Venture Partners—both veterans in scaling biotechnology startups from scientific concept to clinical impact.

Funding Details

Pelage closed a $120 million Series B in October 2025, co-led by ARCH Venture Partners and GV (Google Ventures), with participation from existing backers Main Street Advisors, Visionary Ventures, and YK Bioventures.

The funding will support late-stage development of the company’s lead candidate, PP405, and the initiation of Phase 3 clinical trials in 2026. The capital also positions Pelage to build the operational and manufacturing infrastructure needed to bring a first-in-class regenerative therapy for hair loss to market.

In an industry where most innovation focuses on oncology or rare disease, Pelage’s ability to attract top-tier institutional investors underscores how seriously the field now views regenerative dermatology.

Pipeline & Next Steps

Pelage’s pipeline centers on one program: PP405, its investigational therapy for androgenetic alopecia. The molecule works by metabolically reactivating dormant follicle stem cells—an approach that bypasses hormonal manipulation entirely.

Key milestones on the near horizon include:

• 2026: Initiation of Phase 3 clinical trials
• 2026: Presentation of the full Phase 2a dataset at a major medical meeting

Early data from Phase 2a studies showed rapid follicular activation and visible hair regrowth, suggesting PP405 could offer a faster and more direct mechanism of action than current treatments. Pelage’s goal is to make the therapy effective across diverse hair types and textures, addressing a patient population that spans nearly every demographic.

Market Potential

The market for androgenetic alopecia is massive—tens of millions affected, billions spent each year—but innovation has been stagnant for decades. Finasteride and minoxidil, the current standards of care, are aging stopgaps that manage symptoms rather than restore biology.

Pelage’s competitive advantage lies in doing the opposite. By targeting the stem cell dormancy at the root of hair loss, its therapy aims to restart the follicle’s natural growth cycle. If upcoming trials confirm the safety and efficacy observed so far, PP405 could become the first FDA-approved regenerative treatment for hair loss in more than a generation.

The company’s next challenge is execution: sustaining efficacy over longer studies, proving durable regrowth, and navigating regulatory review. But the early data—showing consistent stem cell reactivation and measurable follicle regeneration—suggests Pelage may be on the cusp of redefining what “treating hair loss” actually means.

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