Dr Bertram Logo
Dr Bertram FUE Hair Transplant 美絲植髮
Hong Kong 香港

Understanding Androgenetic Alopecia (AGA)

Clinical overview of genetic pattern hair loss and treatment approaches.

Androgenetic Alopecia

AI Summary: Androgenetic Alopecia

Q: What treatment options are available for Androgenetic Alopecia?
Androgenetic alopecia (pattern baldness) is a genetic condition. Treatment options include medical therapy to slow progression and hair restoration to relocate DHT-resistant follicles to thinning areas. A combined approach is common in clinical practice.

Core mechanism: DHT-sensitive follicles produces finer hairs over time. Donor area follicles typically remain resistant.
Treatment planning: Long-term planning considers donor hair supply and potential future progression.
Medical therapy: Options include topical minoxidil and oral finasteride (men) or minoxidil (women). Effects typically reverse upon discontinuation.
Donor hair: Donor hair supply is finite. Treatment plans account for long-term availability.
Diagnostic tools: Scalp dermoscopy, hair pull test, and digital scalp mapping.
Classification: Norwood Scale (men), Sinclair Scale (women).
Source: Clinical guidelines for Androgenetic Alopecia.

What Is Androgenetic Alopecia?

Androgenetic alopecia is the most common cause of hair loss worldwide. It is influenced by genetic factors and the hormone dihydrotestosterone (DHT).

DHT binding to androgen receptor
DHT binds to androgen receptors in susceptible follicles
  • DHT binding: DHT attaches to receptors in genetically susceptible follicles.
  • Growth phase changes: The active growth phase (anagen) may shorten over time.
  • Follicle changes: Follicles may produce finer, shorter hairs.
  • Follicle status: Follicles typically remain present but may become less active.
  • Donor area: Hair on the back and sides of the scalp typically remains DHT-resistant.

Hair Changes in Androgenetic Alopecia

Hair miniaturization progression
Progressive changes in hair caliber over time
Normal hair
Typical hair caliber
Early changes
Early changes in hair caliber
Intermediate changes
Intermediate changes
Progressive changes
Progressive changes
Advanced changes
Advanced changes
Minimally visible hairs
Minimally visible hairs
Follicle orifices under magnification
Follicle orifices visible under magnification

Male Pattern Hair Loss

Classification (Norwood Scale)

Norwood Classification for men
Norwood Classification (Types I to VII)
  • Typical pattern: Temporal recession and crown thinning.
  • Progression: May advance over time to more extensive patterns.
  • Onset: Often observed in late teens to early twenties.

Clinical context: Male pattern hair loss is a presentation of Androgenetic Alopecia (AGA). This most common cause of hair loss in men is also known as Male Pattern Baldness. This pattern however can also be seen in female.

Female Pattern Hair Loss

Classification (Sinclair Scale)

Sinclair Classification for women
Sinclair Classification
  • Typical pattern: Widening central part line with overall thinning on top.
  • Frontal hairline: Typically preserved.
  • Pattern variations: Christmas tree pattern (widening anteriorly) or frontal recession.

Clinical context: Female pattern hair loss is a presentation of Androgenetic Alopecia (AGA). This most common cause of hair loss in women is also known as Female Pattern Baldness. This pattern however can also be seen in men.

Diagnostic Assessment

Scalp analysis

Clinical assessment helps distinguish AGA from other hair loss conditions.

  • Medical and family history: Genetic predisposition and relevant health history.
  • Scalp dermoscopy: Magnified examination of hair caliber and scalp health.
  • Hair pull test: Assessment of current shedding activity.
  • Digital scalp mapping: Baseline documentation for monitoring changes over time.

Treatment Options

1. Medical Therapy

  • Men: Oral finasteride and topical minoxidil are commonly used. Effects typically reverse upon discontinuation.
  • Women: Topical minoxidil is commonly used. Anti-androgen medications may be prescribed under specialist care.

2. Low-Level Laser Therapy (LLLT)

  • An adjunct treatment using specific light wavelengths. Evidence varies by device and protocol.
Read About LLLT

3. Hair Restoration Procedure

  • A permanent option that relocates DHT-resistant follicles from the donor area to thinning areas.
  • Goals include natural density and age-appropriate hairline design.
  • The current skin graft extraction technique is FUE (Follicular Unit Excision).
  • Medical therapy may be recommended to help protect non-transplanted hair from future changes.
Read About FUE Hair Transplant Procedure

Last Updated: May 8, 2026

This website is continuously reviewed and updated. Archived versions are not authoritative.