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Dutasteride (Avodart / Zagallo)

Dutasteride (Avodart / Zagallo) is approved in at least one market for androgenetic alopecia, developed by GSK.

Approved for male pattern hair loss in South Korea and Japan, but not in the United States or the European Union.

ApprovedOral5α-reductase inhibitor

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Developed by
GSK
Current phase
Approved

Cleared for sale for a hair-loss indication in at least one market.

Mechanism
5α-reductase inhibitor

Stops testosterone being converted into DHT, the hormone that drives pattern hair loss.

Indications
Androgenetic alopecia
Also known as
Avodart, Zagallo, GG745, dutasteride 0.5 mg
Last public activity
March 2026
Copy last reviewed
September 2026
Record confidence
High

A research record, not medical advice: being listed here says nothing about whether a treatment works or whether it is right for you. Talk to a dermatologist about your own case.

How it is meant to work

Dutasteride inhibits both type I and type II 5-alpha reductase, where finasteride inhibits type II alone. Japan's regulator approved it for androgenetic alopecia in men in 2015 on the grounds that it belongs to the same class as finasteride and matched it in the Phase 2/3 submitted, not on the broader inhibition.

Why it matters

This row is here mostly to fix a common misreading. Dutasteride is frequently described online as either 'not approved' or 'approved' with no qualifier, and both are wrong: it is approved for androgenetic alopecia in men in South Korea and Japan, and only for benign prostatic hyperplasia in the United States and the European Union, where any hair-loss use is off-label. Which of those applies depends entirely on where the reader lives.

Where it is approved

Marketing authorisation is granted country by country, for a specific indication. A drug approved for hair loss in one market may be approved only for something else — or not at all — in another.

  • JapanPMDAApprovedZagallo· prescription only

    Androgenetic alopecia

    Authorised for androgenetic alopecia in 2015; exact date not sourced to a primary document.

    Regulator filing ↗
  • South KoreaMFDSApprovedAvodart· prescription only

    Androgenetic alopecia

    Authorised for androgenetic alopecia in 2009; exact date not sourced to a primary document.

    Peer-reviewed ↗
  • FranceANSMOff-labelAvodart· prescription only

    Hypertrophie bénigne de la prostate

    Widely authorised in France — 28 products, 25 of them marketed — but for benign prostatic hyperplasia. The French summary of product characteristics gives that as the indication; no French authorisation covers hair loss, so use for androgenetic alopecia is off-label here, as in the United States and unlike Japan and South Korea.

    Regulator filing ↗
  • United StatesFDAOff-labelAvodart· prescription only

    Authorised for benign prostatic hyperplasia, not for hair loss. Use for androgenetic alopecia is off-label.

    Peer-reviewed ↗

Development history

  1. Phase 3

    First Phase 3 trial on record: NCT00441116 — A Study To Assess The Efficacy And Safety Of Dutasteride 0.5mg Once Daily For 6 Months In The Treatment Of Male Subjects With Androgenetic Alopecia

    ClinicalTrials.gov ↗

Registered trials

Pulled automatically from ClinicalTrials.gov. Matching is by name and development code, so occasional gaps are possible — tell us if you spot one.

  • NCT05599243Phase 2Completed

    Clinical Trial of Safety and Efficacy of Daily Application of Topical Dutasteride in Men With Androgenic Alopecia.

    Fundacion para la Investigacion Biomedica del Hospital Universitario Ramon y Cajal · n=45 · September 2022

  • NCT02014584Phase 3Completed

    Sexual Function in Men Receiving Dutasteride for Androgenetic Alopecia

    Stiefel, a GSK Company · n=117 · July 2014

  • NCT01929330Phase 1Completed

    Bioequivalence Study of Dutasteride Five 0.1 mg and One 0.5 mg Soft Gelatin Capsules in Healthy Male Volunteers

    GlaxoSmithKline · n=36 · September 2013

  • NCT01831791Phase 3Completed

    A Long-term Study to Determine Safety and Efficacy of Dutasteride in Male Subjects With Androgenetic Alopecia

    GlaxoSmithKline · n=120 · April 2013

  • NCT01231607Phase 3Completed

    Dutasteride Versus Placebo and Finasteride in Men With Androgenetic Alopecia

    GlaxoSmithKline · n=917 · October 2010

  • NCT01004809UnknownCompleted

    AVODART® Alopecia Post-marketing Surveillance (PMS)

    GlaxoSmithKline · n=712 · April 2010

  • NCT00441116Phase 3Completed

    A Study To Assess The Efficacy And Safety Of Dutasteride 0.5mg Once Daily For 6 Months In The Treatment Of Male Subjects With Androgenetic Alopecia

    GlaxoSmithKline · n=153 · December 2006

Listing a trial is not a recommendation to join one. Eligibility, risks and costs vary enormously — discuss any trial with your own doctor first.

Sources

Related programmes

Other programmes in the register with the same mechanism: 5α-reductase inhibitor.

Cite this page

Hair Pipeline, "Dutasteride (Avodart / Zagallo) — development record", hairpipeline.com/pipeline/dutasteride