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Peter R. Feldman, PhD (Medicine)

Founder and Director, Feldman Hair Institute

Evidence-Based Hair Fellow · Certified Trichologist (IAT)

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Peter R. Feldman combines hair biology research, advanced trichology and measurement science in the assessment of persistent, complex and unresolved hair loss. His work focuses on interpreting clinical findings, treatment response and change over time to clarify the next decision.

Peter R. Feldman, Founder and Director of Feldman Hair Institute

Clinical and scientific approach

His approach brings together clinical history, visible distribution, scalp findings, trichoscopy, photographs, investigations, previous treatments and longitudinal measurements. These observations help identify what is supported by the evidence, what remains uncertain and what further information could change a management decision.

This is especially relevant when a diagnosis remains unresolved, hair loss progresses despite care, treatment response is uncertain or measurements and other findings conflict.

Education, training and professional recognition

UEA, Norwich Medical SchoolVisit Norwich Medical School ↗

Doctoral research

PhD (Medicine)

Norwich Medical School, University of East Anglia

Thesis Title
Hair Regeneration

Supervisors
Professor Nicole Horwood
Professor Andrew Messenger

Examiners
Dr Rosemary Davidson
Professor Jeff Donovan

Evidence-Based Hair Fellowship graduate sealVerify graduation ↗

Advanced training

Graduate, Evidence-Based Hair Fellowship

Intensive 1,000-hour advanced education completed over two years in hair loss assessment, diagnosis, treatment and clinical problem-solving.

Program led by Jeff Donovan, MD, PhD.

International Association of Trichologists, Certified TrichologistVerify certification ↗

Professional certification

Certified Trichologist

International Association of Trichologists (IAT #584).

Clinical trichology training completed under David Salinger in Australia.

BSc(Eng), University of the Witwatersrand.

2023 AHRS Mentorship Grant

American Hair Research Society. Mentor: Dominique Van Neste, MD, PhD.

Project: Productivity Measurements of the Hair Follicle and Follicular Unit.

Verify the award ↗ · Read the mentorship experience ↗

Professional background

  • Member of the American Hair Research Society and peer reviewer for dermatology journals.
  • Peter R. Feldman maintains active professional relationships with hair clinicians and researchers internationally, including regular discussions of complex and unresolved cases.
  • Hair loss, measurement and regrowth research presented at international hair research conferences.
  • Lectured international master classes for an advanced trichologist fellowship.

Selected scholarship

Peer-reviewed journal articles

  1. Prolonged Kenogen State (PKS) in Human Scalp Hair Loss: Separating Follicular-Unit Reactivation from Miniaturization Reversal.

    Feldman PR, Donovan J, Westgate GE, Guarrera M, Rushton DH, Mostaghimi A, Seykora JT, Vañó-Galván S, Fiebig K, Tobin DJ, Van Neste D.

    JAAD Reviews. 2026.

    doi:10.1016/j.jdrv.2026.09.005 ↗

  2. Hair Regrowth Treatment Efficacy and Resistance in Androgenetic Alopecia: A Systematic Review and Continuous Bayesian Network Meta-Analysis.

    Feldman PR, Gentile P, Piwko C, et al.

    Frontiers in Medicine. 2023;9:998623.

    doi:10.3389/fmed.2022.998623 ↗ · PMID:36755885

  3. Commentary: Evaluating the Sources and Types of Dietary and Nutritional Advice for Patients with Alopecia Areata.

    Feldman P.

    Archives of Dermatological Research. 2024;316(7):479.

    doi:10.1007/s00403-024-03220-9 ↗ · PMID:39023657

    Read Full Article (View Only)

Invited book chapter

Van Neste D, Feldman PR. Measurements of Hair Growth and Follicular Dynamics. In Agache's Measuring the Skin. Accepted for publication; in production.

Selected World Conference on Hair Research posters

  1. WCHR 2026, P-121: Introducing “Prolonged Kenogen State” (PKS): A Hair Loss Phenotype Driven by Follicular Unit Quiescence.

    Peter R. Feldman, Jeff Donovan, Gillian E. Westgate, Marcella Guarrera, Desmond J. Tobin, Hugh D. Rushton, Arash Mostaghimi, John T. Seykora, Sergio Vañó Galván, Klaus Fiebig, Dominique Van Neste.

  2. WCHR 2024, P055: Reversal of AGA Miniaturised Hairs Observed in Follicular Units over 5 Years.

    Peter Feldman, Boris Mark Mints, Klaus Fiebig, Dominique Van Neste.

  3. WCHR 2024, P206: Androgenetic Alopecia Treatment Evidence Varies Widely in Meta-Analyses: A Call for Consensus in AGA Clinical Research Methods.

    Peter Feldman, Dominique Van Neste, Nicole Horwood, Klaus Fiebig, Andrew Messenger, Jeff Donovan.

Research and innovation

His research examines follicular-unit dynamics, quiescence and reactivation, regenerative biology and immune regulation. Measurement of follicular output, hair-shaft thickness and growth-phase durability supports investigation of treatment response over time.

Critical appraisal of study methods and evidence informs how research is applied to an individual case. Research hypotheses require validation before they can establish diagnostic tools or treatment benefits.

Patented innovation

Botanicals as WNT/β-Catenin Activators, Molecular Pathway Regulators, Tissue Regenerators and Health Biomarker Regulators

Inventors: Peter R. Feldman, Luciano E. Marra, Dennis M. Brown and Deborah J. Cahan.
US Patent 12,708,655 B2.

What this means for a complex case

Patients and practitioners receive independent interpretation of conflicting findings, treatment history, progression and response, with documented recommendations and clear criteria for reassessment. The aim is to clarify the next decision in persistent, unresolved and treatment-resistant hair loss.

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