Understanding Hair Loss

Why Is My Hair Falling Out?

Hair loss is not a diagnosis. It is a symptom with many possible causes.

Understanding the underlying cause is the first step toward finding the right treatment strategy โ€” and avoiding the frustration of addressing the wrong problem.

Setting the Foundation

Not All Hair Loss Is the Same

Many people assume a single cause โ€” or reach for a single product โ€” without considering that different types of hair loss require fundamentally different approaches.

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Pattern Hair Loss

Driven by genetic sensitivity to DHT. Progressive, chronic, and follows predictable patterns. Responds well to treatments that target DHT or stimulate follicle activity โ€” but requires ongoing management.

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Stress-Related Shedding

A temporary increase in follicles entering the resting phase, triggered by physiological or emotional stress. Usually reversible once the trigger is resolved โ€” but often confused with pattern loss.

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Hormonal Changes

Thyroid disorders, postpartum shifts, menopause, and PCOS can all affect the hair cycle. Addressing the underlying hormonal imbalance is typically the most effective approach.

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Nutritional Deficiencies

Iron, vitamin D, zinc, and protein deficiencies are all associated with increased shedding. Easily identifiable with blood testing โ€” and often highly responsive to targeted correction.

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Why the cause matters before the treatment

Minoxidil will not resolve a vitamin D deficiency. Addressing stress won’t stop androgenetic alopecia. The most effective hair loss strategies begin with understanding what is actually happening โ€” and why. This page is your starting point for that process.

The Main Causes

Understanding the Most Common Causes

Each cause operates through different mechanisms and calls for a different response. Here is an overview of the most frequently encountered types of hair loss.

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Most Common Cause

Androgenetic Alopecia

The most prevalent form of hair loss worldwide, affecting both men and women. Androgenetic alopecia is driven by a genetic sensitivity to dihydrotestosterone (DHT) โ€” a hormone derived from testosterone via the enzyme 5-alpha reductase. In susceptible individuals, DHT causes the anagen (growth) phase to shorten progressively and follicles to miniaturise, producing finer, shorter hairs over time until terminal hair production stops.

In men โ€” common signs
  • Receding hairline at the temples
  • Thinning at the crown
  • Progressive pattern following the Norwood scale
  • Gradual onset โ€” often begins in the 20s or 30s
In women โ€” common signs
  • Diffuse thinning across the top of the scalp
  • Widening central part
  • Hairline usually maintained (unlike men)
  • Often becomes more pronounced after menopause
The underlying mechanism
  • Genetic sensitivity to DHT at the follicle receptor level
  • Progressive shortening of the anagen phase
  • Follicle miniaturisation over successive cycles
  • Without intervention: gradual, ongoing progression
Treatment approach
  • DHT-blocking medications (finasteride, dutasteride)
  • Follicle-stimulating treatments (minoxidil)
  • Advanced methods as complementary additions
  • Early intervention produces best outcomes
Learn more about androgenetic alopecia โ†’
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Temporary Shedding

Telogen Effluvium

A temporary but often alarming form of hair shedding in which a significantly larger-than-normal number of follicles simultaneously enter the telogen (resting) phase, leading to a noticeable increase in daily hair loss. Unlike androgenetic alopecia, telogen effluvium is not driven by DHT or genetics โ€” it is a response to an internal disruption. In most cases it is self-limiting and resolves once the underlying trigger is identified and addressed.

Common triggers
  • Illness (particularly fever or infection)
  • Major surgery or hospitalisation
  • Rapid or significant weight loss
  • Severe or prolonged emotional stress
  • Nutritional deficiencies (iron, vitamin D, protein)
  • Childbirth and postpartum hormonal changes
What to expect
  • Increased diffuse shedding โ€” often noticeable on pillows, in the shower
  • Usually temporary โ€” resolves in 3โ€“6 months
  • Addressing the trigger is the primary treatment
  • Nutritional support and scalp health are helpful
Learn more about telogen effluvium โ†’
The delayed onset: Shedding from telogen effluvium typically begins 2โ€“4 months after the triggering event โ€” not immediately. This delay frequently causes confusion, as the shedding appears to have no obvious cause at the time it occurs. Looking back 2โ€“4 months is often where the trigger is found.
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Hormonal Changes

Hormonal Hair Loss

Hair is highly sensitive to hormonal fluctuations. A range of hormonal conditions and life transitions can affect the hair cycle, anagen phase duration, and overall hair density. Hormonal causes of hair loss are particularly common in women and are often underdiagnosed or attributed to other causes.

Thyroid disorders
  • Both hypothyroidism and hyperthyroidism can cause hair loss
  • Diffuse shedding across the scalp
  • Typically resolves with appropriate thyroid treatment
  • Diagnosable with standard blood testing
Postpartum hair loss
  • Oestrogen surges during pregnancy keep hairs in anagen longer
  • After birth, oestrogen drops and many follicles enter telogen simultaneously
  • Increased shedding typically begins 2โ€“4 months postpartum
  • Usually temporary โ€” resolves within 6โ€“12 months
Menopause
  • Declining oestrogen can unmask genetic sensitivity to androgens
  • Pattern similar to female androgenetic alopecia
  • Diffuse thinning at the crown and parting
  • May benefit from both hormonal and non-hormonal approaches
PCOS and testosterone
  • Polycystic ovary syndrome is associated with elevated androgens in women
  • Can trigger female pattern hair loss and accelerate miniaturisation
  • DHT-related mechanisms similar to male androgenetic alopecia
  • Managing androgen levels may improve hair loss outcomes
Learn more about hormonal hair loss โ†’
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Common Trigger

Stress and Hair Loss

Stress โ€” both acute and chronic โ€” is one of the most frequently mentioned factors in discussions of hair loss. Its role is real but often misunderstood. Stress can trigger or worsen hair shedding through several mechanisms, but it rarely operates as a sole cause in isolation.

How stress affects hair
  • Elevated cortisol may push follicles into telogen prematurely
  • Physiological stress (illness, surgery) triggers telogen effluvium
  • Chronic stress may worsen androgenetic alopecia in predisposed individuals
  • Shedding typically begins 2โ€“4 months after the stressful period
What stress cannot do
  • Stress alone does not cause androgenetic alopecia
  • Managing stress will not reverse pattern hair loss
  • Stress is typically an amplifier, not a primary cause
  • If hair loss continues after stress resolves, other causes should be investigated
Learn more about stress-related hair loss โ†’
Stress-related shedding is usually temporary. If shedding continues beyond 6 months after a stressful period has resolved, it is worth investigating whether an underlying cause such as androgenetic alopecia or a nutritional deficiency is also present.
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Female Hair Loss

Hair Loss in Women

Women experience many of the same underlying causes as men โ€” but the presentation, triggers, and treatment considerations are often meaningfully different. Female hair loss is also more commonly multi-factorial, involving a combination of hormonal, nutritional, and genetic influences occurring simultaneously.

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Female Pattern Hair Loss

Diffuse thinning across the top of the scalp โ€” the hairline is usually preserved. Driven by androgen sensitivity, often becomes more evident after menopause.

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Postpartum Shedding

A natural and usually temporary increase in shedding 2โ€“4 months after childbirth as oestrogen levels normalise. Resolves in most cases within 6โ€“12 months.

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Iron Deficiency

One of the most common and most correctable causes of hair shedding in women. Low ferritin is a particularly important marker โ€” often missed by standard iron panels.

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Thyroid Disorders

Both over and underactive thyroid can cause diffuse hair loss. Easily screened with blood testing and typically responsive to appropriate medical treatment.

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Menopause

Declining oestrogen at menopause can unmask androgen sensitivity and accelerate follicle miniaturisation โ€” similar in mechanism to male pattern hair loss but distinct in presentation.

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PCOS

Elevated androgens in women with PCOS can drive pattern hair loss. Managing androgen levels through hormonal treatment may improve both scalp and systemic symptoms.

Learn more about hair loss in women โ†’
Self-Assessment

How to Identify the Most Likely Cause

Answer these questions to help narrow down the most likely cause of your hair loss and find the right deep-dive guide to explore next.

1
Is your hairline receding, or is thinning concentrated at the crown?
If yes โ€” this pattern is consistent with androgenetic alopecia. The hairline recession and crown thinning pattern is characteristic of DHT-driven miniaturisation. Explore the androgenetic alopecia guide โ†’
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2
Did the shedding begin suddenly, or follow an illness, surgery, or stressful event?
If yes โ€” you may be experiencing telogen effluvium. Remember that shedding often begins 2โ€“4 months after the triggering event. Explore the telogen effluvium guide โ†’
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3
Have you recently given birth, entered menopause, or been diagnosed with a thyroid condition or PCOS?
If yes โ€” hormonal changes are likely a significant factor. Explore the hormonal hair loss guide โ†’
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4
Have you experienced significant stress, rapid weight loss, or dietary restriction recently?
If yes โ€” stress-triggered telogen effluvium or nutritional deficiency may be contributing. Blood testing for iron, ferritin, vitamin D, and thyroid can help clarify this. Explore stress and hair loss โ†’
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5
Is thinning gradual and worsening over years, or was the onset sudden?
Gradual progression over years suggests androgenetic alopecia. Sudden onset or rapid progression suggests a systemic trigger โ€” consider blood testing and professional evaluation. Explore hair growth foundations โ†’
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When in doubt, get tested

Blood testing for ferritin (stored iron), full iron panel, vitamin D, thyroid function (TSH, T3, T4), and relevant hormonal markers can clarify many cases of hair loss that are otherwise difficult to diagnose from symptoms alone. A GP or dermatologist can guide appropriate testing for your situation.

Understanding Hair Loss

Hair Shedding Patterns: What the Shape of Hair Loss Can Tell You

Many people focus on the amount of hair they lose, but the pattern of thinning and shedding can sometimes provide clues about the underlying cause. Different hair loss conditions often affect different areas of the scalp, which is why understanding common shedding patterns can be helpful when deciding what to investigate next.

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Diffuse Thinning Across the Entire Scalp

Hair appears thinner everywhere rather than in specific zones. Overall density decreases and the part line may look wider over time. This pattern is commonly associated with telogen effluvium, illness, nutritional deficiencies, medications, rapid weight loss, or hormonal changes. It can also arise following periods of significant physiological or emotional stress.

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Progressive Thinning at the Crown and Part Line

Gradual reduction in density centred around the top of the scalp, with a widening central part and increasing scalp visibility. This is a hallmark pattern of female pattern hair loss and androgenetic alopecia — a condition influenced by genetic predisposition and hormonal factors.

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Receding Hairline and Temple Thinning

Recession around the temples, changes to the shape of the hairline, or thinning at the frontal scalp are characteristic features of male pattern hair loss. This follows a well-recognised progression linked to androgenetic alopecia and the effects of dihydrotestosterone (DHT) on genetically susceptible follicles.

Patchy Hair Loss

Distinct, localised areas of missing hair — often circular or irregular — that differ from the more gradual thinning seen in common pattern hair loss. Patchy loss can have a range of causes and may warrant evaluation by a dermatologist to determine whether conditions such as alopecia areata or scalp-related issues may be involved.

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Sudden Increase in Daily Shedding

A noticeable increase in hair found in the shower drain, on a hairbrush, or on the pillow — often occurring two to four months after a triggering event. This delayed shedding pattern is frequently seen in telogen effluvium, where a physiological shock pushes large numbers of follicles into the resting phase. Common triggers include major stress, illness, surgery, rapid weight loss, and significant dietary changes.

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Patterns are clues, not diagnoses

Hair shedding patterns can offer useful clues, but they are only one piece of the puzzle. Similar-looking thinning can sometimes have very different underlying causes. Understanding the pattern may help guide further investigation, but accurate diagnosis should be based on a complete assessment of symptoms, medical history, and potential underlying triggers — ideally with evaluation by a dermatologist or qualified healthcare professional.

Video Examples

Hair Shedding Concepts in Practice

The following short videos from Sofia Hair Health (@sofiahairhealth) illustrate some of the hair loss concepts discussed above. They are provided as educational visual examples and do not form the basis of the factual content on this page.

Video 1

@sofiahairhealth — Is your hair loss being caused by DHT, stress or nutrition?

Illustrates how to consider whether hair loss may be linked to DHT, nutritional factors, or stress — based on the overall pattern of symptoms.

Video 2

@sofiahairhealth — Too Much Hair Falling Out? A simple self-check

Demonstrates a simple self-check method to help assess whether increased daily shedding may be a concern worth investigating further.

Video 3

@sofiahairhealth — DHT or Not DHT? Identifying the pattern

Explores physical signs that may indicate DHT-driven hair loss, including scalp characteristics and thinning location — contrasting this with other types of hair loss causes.

Video 4

@sofiahairhealth — 7 signs your hair loss is becoming chronic

Outlines warning signs that temporary hair shedding may be transitioning into a more persistent pattern, which may indicate the need for professional assessment.

Common Questions

Frequently Asked Questions

Honest answers to some of the most commonly searched questions about hair loss causes โ€” including a few persistent myths worth addressing directly.

๐Ÿ‹๏ธFrequently Asked

Does creatine cause hair loss?

One study found elevated DHT in rugby players using creatine โ€” but no study has directly linked creatine to measurable hair loss. Those with strong genetic predisposition to androgenetic alopecia may choose caution, but the current evidence does not establish creatine as a cause of hair loss in healthy individuals.

Creatine and hair loss guide โ†’
๐Ÿ’ŠFrequently Asked

Do Ozempic or weight loss drugs cause hair loss?

Hair loss associated with GLP-1 medications like Ozempic, Wegovy, and Mounjaro is most likely a consequence of rapid weight loss triggering telogen effluvium โ€” not a direct drug effect. This shedding is typically temporary and resolves as weight and nutrition stabilise.

Weight loss drugs and hair loss โ†’
๐ŸงขCommon Myth

Does wearing a hat cause hair loss?

No. Hair follicles receive oxygen and nutrients through the bloodstream โ€” not from air exposure. The idea that hats suffocate follicles has no biological basis. Hats do not cause androgenetic alopecia or any other form of permanent hair loss.

Hat myth guide โ†’

Can stress cause hair loss?

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Yes, stress can trigger telogen effluvium โ€” a temporary form of shedding where elevated cortisol and physiological stress push a larger-than-normal number of follicles into the resting phase. Shedding typically begins 2โ€“4 months after the stressful period. Stress generally acts as a trigger or amplifier rather than a sole cause โ€” particularly for those with an existing predisposition to androgenetic alopecia.

Is hair loss reversible?

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It depends on the cause. Telogen effluvium triggered by stress, illness, or nutritional deficiency is usually temporary and resolves once the underlying trigger is addressed. Androgenetic alopecia involves progressive follicle miniaturisation and is not self-reversing, though it can be slowed or partially reversed with early, consistent treatment.

How much hair loss is normal?

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Losing 50โ€“100 hairs per day is considered within the normal range as part of the natural hair cycle’s exogen (shedding) phase. This amount is typically replaced by new growth under normal circumstances. Shedding that noticeably exceeds this, results in visible thinning, or is accompanied by bald patches warrants attention.

When should I see a doctor about hair loss?

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Consider seeing a healthcare professional if: hair loss is sudden or rapid rather than gradual; you are losing hair in patches rather than diffusely; the scalp is inflamed, itchy, or scaly; hair loss is accompanied by other symptoms such as fatigue, weight changes, or irregular periods; or if self-directed approaches have not produced results after several months.
Know When to Act

When to Seek Professional Help

Self-directed research and evidence-based habits are valuable โ€” but some situations call for professional evaluation rather than a DIY approach.

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See a healthcare professional if any of the following apply

Most gradual hair thinning can be explored and managed with the guidance available on this site. However, some presentations suggest underlying medical conditions that require professional diagnosis and treatment.

  • Hair loss is sudden โ€” noticeable within days or a few weeks
  • Hair loss is severe โ€” losing significantly more than 100 hairs per day
  • Bald patches appear โ€” particularly circular or irregular patches (may indicate alopecia areata)
  • The scalp is inflamed, itchy, scaling, or painful
  • Hair loss is accompanied by other symptoms โ€” fatigue, weight changes, skin changes, or irregular periods
  • Hair loss progresses rapidly despite consistent treatment
  • You are unsure of the cause after ruling out common triggers
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Understand the Cause. Then Choose the Response.

The right information leads to the right strategy. Hair loss is a symptom, not a verdict โ€” and in most cases, understanding what is driving it opens a clear path toward addressing it effectively.

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