Androgenetic Alopecia (AGA)
Also known as Male Pattern Baldness or Female Pattern Baldness.
The most common cause of hair loss in men and women.
Androgenetic alopecia (pattern hair loss) is a progressive condition in which susceptible hair follicles gradually shrink in response to androgens—particularly dihydrotestosterone (DHT). This leads to shorter, finer hairs and, over time, visible thinning across characteristic areas of the scalp.
It is the leading cause of hair loss worldwide, with well-established patterns:
In men: recession at the temples and crown
In women: diffuse thinning over the top of the scalp with preservation of the frontal hairline
While extremely common, it is often misunderstood. Androgenetic alopecia is not simply “cosmetic”—it is a biological process with a defined mechanism, and one that can be assessed and managed based on current scientific evidence.
What Is Actually Happening in Androgenetic Alopecia?
Androgenetic alopecia is driven by a process known as follicular miniaturisation—a gradual transformation of healthy, thick terminal hairs into finer, shorter hairs over successive growth cycles.
At a biological level, three key processes are involved:
1. Genetic Sensitivity to Androgens
Hair follicles in certain areas of the scalp (particularly the top) are genetically programmed to be more sensitive to androgens such as dihydrotestosterone (DHT).
This sensitivity—not the absolute level of hormones—is what drives the condition.
2. Progressive Shortening of the Growth Phase
Each hair grows in cycles. In androgenetic alopecia:
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The anagen (growth) phase becomes shorter
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The telogen (resting/shedding) phase becomes proportionally longer
Over time, hairs do not grow long enough or thick enough to maintain coverage.
3. Gradual Follicle Miniaturisation
With each cycle:
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Hair shafts become thinner and less pigmented
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Follicles produce vellus-like hairs instead of terminal hairs
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Eventually, some follicles may become dormant
This is why patients often notice:
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“My hair is still there—but it’s thinner”
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“My scalp is becoming more visible”
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“My hair won’t grow as long as it used to”
It is a Patterned Process — Not Random Hair Loss
One of the defining features of androgenetic alopecia is that it follows predictable, anatomically defined patterns:
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The frontal scalp and crown are typically affected
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The back and sides are relatively resistant
This reflects underlying biological differences in follicle behaviour across the scalp.
Understanding this process is key—because effective management is not about “stimulating hair growth” in general, but about targeting the specific biology driving follicle miniaturisation.
Who Does Androgenetic Alopecia Affect — and When Does It Start?
Androgenetic alopecia can affect both men and women, but the age of onset, pattern, and progression differ.
In Men
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Can begin as early as the late teens or early 20s
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Often first noticed as:
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Recession at the temples
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Thinning at the crown
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Progression is typically gradual but continuous
By age 50, around 50% of men will have clinically significant androgenetic alopecia, with prevalence increasing steadily with age.
In Women
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Usually presents later than in men, most commonly:
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From the 30s onwards
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Increasing around perimenopause and menopause
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Typically appears as:
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Diffuse thinning over the top of the scalp
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With preservation of the frontal hairline
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By age 50, approximately 25–40% of women are affected to some degree.
Early vs Late Onset — Why It Matters
Earlier onset often indicates a stronger genetic predisposition and may be associated with:
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Faster progression
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Greater lifetime hair loss
Later onset tends to be more gradual, particularly in women, but can still become significant over time.
A Lifelong Process, Not a Sudden Event
Androgenetic alopecia does not typically present as sudden shedding. Instead, patients often describe:
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“My hair has been getting thinner over years”
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“My parting is widening”
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“It doesn’t feel as thick as it used to”
This slow progression is why it is often noticed late—but biologically active much earlier.
The next step is distinguishing androgenetic alopecia from other causes of hair loss—because not all thinning follows this pattern, and accurate diagnosis is essential before considering treatment.
How is Androgenetic Alopecia Diagnosed?
Diagnosing androgenetic alopecia should be done by a Dermatologist. Diagnosis is primarily clinical, but accurate confirmation requires a structured assessment. It is important to remember that not all hair thinning is androgenetic alopecia, and successful management depends on getting the diagnosis right.
1. Clinical History
A detailed history often provides the first clues:
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Gradual onset over months to years
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Family history of similar hair loss
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Absence of sudden shedding (which can suggest conditions like telogen effluvium)
In women, it is also important to ask about:
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Menstrual history
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Menopause
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Symptoms of androgen excess (e.g. acne, hirsutism)
2. Pattern Recognition
Androgenetic alopecia follows predictable patterns:
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Men: recession at the temples and thinning at the crown
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Women: widening of the central part with diffuse thinning over the top
These patterns can be helpful in distinguishing from other conditions, but it is not always clear.
3. Trichoscopy (Scalp Dermoscopy)
This is one of the most useful tools in clinic.
Typical findings include:
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Variation in hair shaft diameter (miniaturisation)
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Increased number of thin, vellus-like hairs
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Reduced density in affected areas
These features are considered hallmarks of androgenetic alopecia and can often confirm the diagnosis without the need for biopsy.
4. Hair Pull Test (Supportive, Not Diagnostic)
A gentle traction test may be performed:
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Usually negative or only mildly positive in androgenetic alopecia
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Strongly positive results suggest alternative diagnoses (e.g. active shedding disorders)
5. Blood Tests — When Indicated
Blood tests are not required to diagnose androgenetic alopecia, but may be used to:
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Exclude other contributing factors (e.g. iron deficiency, thyroid dysfunction)
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Assess hormonal profiles in selected female patients
6. When Is a Biopsy Needed?
Rarely required, but considered if:
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The diagnosis is unclear
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There are signs of scarring or inflammation
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Hair loss is atypical or rapidly progressive
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Key Point
Androgenetic alopecia is usually confirmed through a combination of:
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History
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Pattern recognition
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Trichoscopic findings
Not every patient with thinning hair has androgenetic alopecia—and not every androgenetic alopecia patient presents in a textbook way.
Once the diagnosis is confirmed, the next question becomes: what can realistically be done—and what does the evidence actually support?
Which Treatments for Androgenetic Alopecia Actually Work?
There are only a small number of treatments with credible clinical evidence for androgenetic alopecia. Most fall into two categories:
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Targeting the underlying biology (androgens and follicle miniaturisation)
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Supporting follicle function and hair cycling
Understanding this distinction is key—because many widely marketed treatments do neither.
Treatments with Strong Evidence
1. Minoxidil (Topical)
Minoxidil
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Widely studied and licensed for androgenetic alopecia
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Prolongs the anagen (growth) phase and increases hair diameter
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Works in both men and women
What to expect:
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Stabilisation of hair loss is more common than dramatic regrowth
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Results take 3–6 months to become noticeable
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Continued use is required to maintain effect
2. Finasteride (Oral, Men)
Finasteride
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Reduces conversion of testosterone to DHT, the key driver of follicle miniaturisation
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Strong evidence for slowing progression and improving density in men
What to expect:
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Most effective for maintaining and thickening existing hair
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Requires ongoing use
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Requires careful discussion of risks and suitability
3. Platelet-Rich Plasma (PRP)
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Uses concentrated growth factors derived from the patient’s own blood
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Increasing body of evidence supports improvements in hair density and thickness
What to expect:
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Works best in early to moderate androgenetic alopecia
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Requires a course of treatments and maintenance
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Outcomes vary depending on protocol and patient factors
4. Low-Level Laser Therapy (LLLT)
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Medical-grade light devices (e.g. laser caps/helmets)
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Thought to improve cellular energy production within follicles
What to expect:
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Modest but measurable improvements in some patients
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Requires consistent, long-term use
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Often used as an adjunct rather than standalone treatment
A Realistic Perspective
No treatment “cures” androgenetic alopecia.
The goals are typically to:
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Slow or stabilise progression
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Improve hair thickness and density
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Preserve existing follicles for as long as possible
Early intervention generally leads to better outcomes—because once follicles are lost or severely miniaturised, they are more difficult to recover.
The key question then becomes: which of these treatments is appropriate for you, based on your stage, pattern, and goals?
Which Treatment Is Right for You?
There is no single “best” treatment for androgenetic alopecia. The right approach depends on stage of hair loss, pattern, biology, and personal preferences. A structured, individualised plan is far more effective than a one-size-fits-all approach.
Step 1: Identify Your Stage
Early Thinning
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Subtle reduction in density
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Hair still present but finer
Typical approach:
Goal: Stabilise early and preserve as much hair as possible
Moderate Hair Loss
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Visible scalp through hair
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Noticeable recession or widening part
Typical approach:
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Combination therapy:
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Minoxidil
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Finasteride (men, if appropriate)
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PRP course + maintenance
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Adjuncts (LLLT, microneedling)
Goal: Slow progression and improve density where follicles are still active
Advanced Hair Loss
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Large areas of thinning or baldness
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Long-standing follicle miniaturisation
Typical approach:
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Medical treatments may still help preserve remaining hair
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Consideration of:
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Hair transplantation
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Cosmetic options (fibres, scalp micropigmentation)
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Goal: Realistic improvement + preservation, not full restoration
Step 2: Consider Your Biology
Not all patients respond in the same way. Key factors include:
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Genetic sensitivity to androgens
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Duration of hair loss
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Age and hormonal status
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Scalp health and follicle viability
This is why two people with similar-looking hair loss can respond very differently to the same treatment.
Step 3: Define Your Goals
Different patients want different outcomes:
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Stabilisation only → often achievable with medical therapy alone
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Thickening and cosmetic improvement → combination approaches
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Maximal restoration → may involve surgical + medical strategies
Clarity here avoids unrealistic expectations and guides appropriate treatment selection.
A Practical Framework
In most cases:
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Foundation:
Evidence-based medical therapy (e.g. minoxidil ± finasteride) -
Advanced options:
Transplant or cosmetic camouflage when needed
Key Point
The earlier treatment is started, the more options are available—and the better the likely outcome.
If you’re unsure where you sit, the most useful first step is a structured assessment—looking at pattern, progression, and follicle behaviour—so that any treatment plan is based on evidence, not guesswork.
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What Actually Happens In Androgenetic Alopecia?
Androgenetic alopecia is not simply “hair falling out.”
It is a gradual biological process in which genetically susceptible hair follicles slowly become smaller over time — a process known as follicular miniaturisation.
At first, hairs may simply look thinner, finer, softer, or shorter than they used to. Over time, the hair growth cycle changes:
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The growth phase (anagen) becomes shorter
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The resting phase (telogen) becomes longer
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Hair follicles produce thinner hairs
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Hair density gradually reduces
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Some follicles may eventually become extremely miniaturised
This is why many people notice that their hair no longer grows as long or thick as it once did before visible thinning develops.
Why Does This Happen?
Dihydrotestosterone (DHT) plays an important role in genetically susceptible follicles, particularly around the temples, frontal scalp, and crown.
But modern research suggests androgenetic alopecia is more complex than DHT alone.
Hair follicles are controlled by intricate biological signalling systems that regulate:
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Hair growth
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Stem cell activity
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Inflammation
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Blood supply
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Cellular energy production
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Hair cycle timing
In androgenetic alopecia, these systems become progressively disrupted.
Research suggests this may involve:
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Increased DHT signalling
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Suppression of hair-growth signalling pathways such as WNT/β-catenin
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Increased inflammatory signalling
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Oxidative stress
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Reduced follicular support and blood vessel signalling
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Changes in stem cell behaviour within the follicle
Over time, this creates an environment where healthy thick terminal hairs gradually transform into finer miniaturised hairs.
Why Early Treatment Matters
Because androgenetic alopecia is progressive, earlier intervention may help preserve more existing hair follicles before miniaturisation becomes advanced.
The goal of treatment is usually to:
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Slow progression
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Support follicle function
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Improve hair density and thickness
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Prolong the growth phase
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Create a healthier environment for hair follicles
Different treatments aim to influence different parts of this biological process.
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The Hair Growth Cycle
Hair follicles continuously cycle through different phases throughout life.
Anagen (growth phase)
This is the active growth phase where hair grows longer and thicker. On a healthy scalp, most hairs are normally in this phase.
Catagen (transition phase)
A short transition stage where the follicle begins to shrink and hair growth slows.
Telogen (resting phase)
The follicle rests before the hair eventually sheds and the cycle begins again.
In androgenetic alopecia, this cycle gradually changes:
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the growth phase becomes shorter
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the resting phase becomes longer
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follicles become progressively smaller
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hairs become finer and shorter over time
This process is called follicular miniaturisation.
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Why Is It Called “Patterned” Hair Loss?
Androgenetic alopecia is often called “patterned hair loss” because it tends to affect predictable areas of the scalp rather than causing uniform hair loss everywhere.
In men, this commonly begins:
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at the temples
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along the frontal hairline
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at the crown
Over time, these areas may gradually connect, creating the familiar “male pattern” of hair loss.
In women, the pattern is usually different. Hair thinning often develops more diffusely across the top of the scalp, with widening of the central parting, while the frontal hairline is often preserved.
One of the most fascinating aspects of androgenetic alopecia is that some follicles are much more genetically resistant than others. Hair follicles on the back and sides of the scalp are often less sensitive to the biological signals that drive miniaturisation.
This difference in follicle behaviour is also the reason hair transplantation works. Resistant follicles from the back and sides of the scalp can often continue growing even after being moved to thinning areas.
This phenomenon is sometimes referred to as “donor dominance” - the observation that transplanted follicles often continue behaving more like the resistant donor area they came from rather than the balding area they are moved into.
Researchers believe these patterns relate to regional differences in:
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androgen receptor activity
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DHT sensitivity
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follicular signalling pathways
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enzyme activity
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genetics
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local scalp biology
This is why androgenetic alopecia is not simply “hair loss” but a highly patterned biological process affecting genetically susceptible follicles.
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Inflammation, Oxidative Stress, And The Scalp Environment
Androgenetic alopecia is increasingly understood as more than a purely hormonal condition.
Research suggests some people with androgenetic alopecia may also develop low-grade inflammation around affected hair follicles. This is sometimes called perifollicular inflammation.
Oxidative stress may also play a role. Oxidative stress occurs when cells are exposed to excessive unstable molecules known as free radicals, which can damage cellular structures over time.
Researchers are investigating whether inflammation, oxidative stress, vascular changes, and alterations in the local scalp environment may contribute to progressive follicular miniaturisation in genetically susceptible individuals.
This does not mean inflammation alone causes androgenetic alopecia. DHT and genetic susceptibility still appear central to the condition. However, modern research suggests the biological picture is more complex than previously thought.
This growing understanding is one reason why some modern treatment approaches aim not only to reduce DHT signalling, but also to support follicular health, wound healing pathways, and the scalp environment more broadly.
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How Androgenetic Alopecia Progresses Over Time
Androgenetic alopecia is usually a progressive condition.
In many people, the process develops gradually over years or decades rather than happening suddenly.
Early signs may include:
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reduced hair density
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increased scalp visibility
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widening of the parting
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recession at the temples
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reduced ponytail thickness
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finer hairs around affected areas
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hair that no longer grows as thick or as long as before
Over time, affected follicles may continue to miniaturise. Thick terminal hairs gradually become finer, shorter, softer hairs until some follicles may eventually produce very little visible hair at all.
The rate of progression varies significantly between individuals and may be influenced by:
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genetics
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age
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hormonal factors
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overall health
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inflammation
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environmental factors
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treatment use
Some people experience relatively slow progression over decades, while others notice more rapid changes earlier in life.
This progressive nature is one reason why earlier assessment and treatment may help preserve more existing hair follicles before miniaturisation becomes advanced.
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Not All Hair Loss Is Androgenetic Alopecia
Not all hair shedding or thinning is caused by androgenetic alopecia.
Hair loss can occur for many different reasons, including:
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telogen effluvium (stress-related shedding)
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alopecia areata
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nutritional deficiencies
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hormonal disorders
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inflammatory scalp disease
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medication side effects
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traction alopecia
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scarring alopecias
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systemic illness
Some people may also have more than one type of hair loss occurring at the same time.
This is one reason why proper assessment matters. Diagnosing hair loss accurately may involve:
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medical history
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scalp examination
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trichoscopy
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blood tests in selected cases
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assessment of hair loss pattern and progression
Understanding the underlying diagnosis is important because different forms of hair loss can behave very differently and may require very different treatment approaches.
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How Is Androgenetic Alopecia Diagnosed?
Diagnosis is usually based on a combination of:
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pattern of hair loss
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scalp examination
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assessment of follicular miniaturisation
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medical history
In many cases, trichoscopy can provide additional useful information. Trichoscopy is a form of scalp and hair imaging that allows closer assessment of hair follicle patterns and hair shaft variation.
Features commonly seen in androgenetic alopecia may include:
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variation in hair shaft diameter
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increased miniaturised hairs
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reduced hair density in characteristic areas
In selected cases, additional investigations such as blood tests may also be considered to help identify contributing factors or exclude other causes of hair loss.