Seasonal Hair Shedding: Why Hair May Shed More in Fall

Man outdoors in sunlight illustrating seasonal hair shedding in late summer and fall

Seasonal hair shedding is a temporary increase in the number of hairs released from the scalp. Human studies have identified seasonal patterns in hair cycling, often with more resting, or telogen, hairs during summer. However, not every increase in shedding is seasonal, and the precise biological cause remains uncertain.

Written by Dr. Kristen Rogers. Updated September 2026.

Key Takeaways

Human studies support the existence of seasonal variation in scalp-hair cycling.
Some studies have found the highest proportion of resting hairs during summer, followed by increased shedding as summer transitions into fall.
Hair follicles contain molecular clocks that help regulate follicular activity, but their role in seasonal shedding has not been established.
Persistent shedding, visible loss of density, focal patches or scalp symptoms should not automatically be attributed to the season.
Gentle hair care can protect the scalp and strands, but it cannot correct an underlying medical cause of excessive shedding.

Many people notice more hair in the shower, on a pillow or in a brush as summer transitions into fall. This can feel sudden, particularly when several days of released hairs become visible during washing.

Research suggests that seasonal variation in human hair growth is real. The more difficult question is why it happens.

The hair follicle responds to hormonal, immune, metabolic and environmental signals. These systems create several plausible connections between changing seasons and hair cycling, but science has not identified one simple cause.

What Is Seasonal Hair Shedding?

Seasonal hair shedding describes a recurring increase in hair release during particular times of year. It is not a separate medical diagnosis and does not necessarily mean that someone is developing permanent hair loss.

Hair moves through four primary stages:

Anagen: The active growth phase, during which the follicle produces the hair shaft.
Catagen: A short, regulated transition in which growth stops and the lower follicle regresses.
Telogen: A relative resting phase during which the non-growing hair remains within the follicle.
Exogen: The release of the hair shaft from the follicle.

A hair does not necessarily fall out as soon as its follicle leaves anagen. There can be a delay between the biological transition into telogen and the moment the hair is visibly released.

For a closer look at these stages, see Understanding the Hair Growth Cycle.

Human hair cycle showing anagen, catagen, telogen and exogen follicle stages — The human hair cycle includes growth, regression, rest and hair-shaft release. Exogen can occur independently of the core anagen–catagen–telogen sequence.

Does Hair Really Shed More in Fall?

Seasonal variation has been observed in human studies, although the timing and magnitude differ among individuals.

A landmark study published in 1991 followed 14 healthy White men for 18 months. Researchers observed a seasonal pattern in the proportion of scalp hairs in telogen, with a prominent peak during summer and a smaller peak in spring. Because telogen is followed by release, a summer increase in resting hairs may become noticeable as increased shedding later in summer or during fall.

A larger retrospective study published in 2009 evaluated trichograms from 823 women who had sought evaluation for hair-loss concerns. Researchers also found seasonal variation, including a summer peak in telogen hairs.

These studies support the existence of seasonal changes in human hair cycling. They do not prove that everyone sheds more in fall, and they do not establish the mechanism responsible.

The research also has limitations. The first study was small, while the second examined women who were already concerned about hair loss rather than a randomly selected population. Climate, latitude, age, hormonal status and individual health may all influence whether someone notices a seasonal pattern.

Human studies showing seasonal variation in telogen hair during summer — Human studies have reported seasonal variation in telogen hairs, including summer peaks, but they do not establish one universal shedding season or cause.

Evidence at a Glance: What We Know and What Remains Uncertain

Question	What the evidence supports	What remains uncertain
Is shedding seasonal?	Human studies have found seasonal variation in scalp-hair cycling.	The pattern does not occur equally in everyone.
When does it occur?	Studies have reported summer peaks in telogen hairs and a smaller spring fluctuation.	There is no universal start date, end date or duration.
What causes it?	Hair follicles respond to hormonal, metabolic and environmental signals and contain circadian machinery.	No single mechanism, including daylight, hormones, ultraviolet exposure or the follicular clock, has been proven to cause ordinary seasonal shedding.
Is it always harmless?	A temporary, diffuse change that returns to baseline may be consistent with seasonal variation.	Persistent shedding or declining density may indicate another condition and deserves evaluation.

When Is Hair Shedding Season?

There is no universal hair-shedding season.

Available human studies most consistently identify an increase in telogen hairs during summer. Because resting hairs may be released later, people may notice more shedding during late summer and early fall.

A smaller spring fluctuation has also been reported. This suggests that human hair cycling may have more than one seasonal variation rather than one fixed annual shedding event.

Research has not established an exact date when seasonal shedding begins or ends.

How Long Does Seasonal Hair Shedding Last?

There is not enough evidence to assign seasonal shedding a universal duration such as four, six or eight weeks.

The length of noticeable shedding depends on how many follicles entered telogen, how closely their cycles aligned and whether another cause of shedding is present. Washing frequency and hair length can also influence how dramatic the shedding appears.

A short-lived increase that returns to a person’s usual baseline without visible loss of density may be consistent with seasonal variation. Shedding that continues, becomes progressively heavier or is accompanied by thinning should not automatically be considered seasonal.

How Much Hair Shedding Is Normal?

Hair shedding is a normal part of the hair cycle, but counting individual hairs is an imperfect way to determine whether something is wrong.

The frequently quoted estimate of 50 to 100 hairs per day is only a general reference. What someone sees depends on:

How frequently the hair is washed or brushed
Hair length and texture
Whether released hairs remain trapped within curls or protective styles
Recent illness, stress, surgery, pregnancy or weight change
Medications and hormonal changes
Nutritional status
The person’s usual baseline

Someone who washes their hair every several days may see several days of released hairs at once. Long hairs also occupy more visual space, making the same number of hairs appear more dramatic.

A sustained change from an individual’s normal pattern is often more informative than one isolated hair count.

Could the Hair Follicle’s Biological Clock Be Involved?

Human hair follicles contain molecular circadian machinery, including the clock proteins BMAL1 and PER1. Laboratory experiments using cultured human scalp follicles found that reducing these proteins altered follicular cycling and prolonged anagen.

This establishes that clock genes participate in human follicle biology. It does not prove that shorter autumn days reset the follicular clock and cause fall shedding.

Circadian rhythms operate over approximately 24 hours, while seasonal or circannual rhythms occur across the year. The two timing systems may interact, but the connection remains an emerging area of research.

A forthcoming Origenere guide will examine the hair follicle’s circadian clock, including BMAL1, PER1 and how biological timing may influence hair growth, cycling and pigmentation.

What Might Connect the Seasons to Hair Cycling?

Several mechanisms have been proposed, but none fully explains seasonal shedding in humans.

Changing Daylight

The number of daylight hours changes throughout the year. Photoperiod strongly affects seasonal coat growth and shedding in many mammals.

Human scalp hair retains measurable seasonality, but the effect is far less pronounced. A direct pathway connecting shorter days with human fall shedding has not been established.

Neuroendocrine Signals

Hair follicles can respond to thyroid hormones, melatonin, cortisol, sex hormones and other signaling molecules. Some of these signals vary with time of day, health status or season.

Their effects on follicles make them plausible mediators, but current evidence does not identify one hormone as the cause of ordinary seasonal shedding.

Environmental Exposure

Sunlight, heat, lower humidity and changes in hair-care practices can affect the scalp and hair shaft.

Ultraviolet radiation may contribute to oxidative damage, pigment fading, protein degradation, dryness and breakage of the exposed hair shaft. These effects can make hair appear thinner or more fragile, but hair-shaft damage and shedding from the follicle are different processes.

Current evidence does not establish cumulative summer ultraviolet exposure as the primary cause of normal seasonal shedding. See How UVA and UVB Affect Hair and Scalp for a detailed explanation of photodamage.

Seasonal Hair Shedding Versus Hair Loss

Shedding describes the release of hair shafts. Hair loss is a broader term that can include excessive shedding, progressive follicular miniaturization, inflammatory disease, scarring or loss of follicular activity.

A temporary seasonal pattern is more likely to:

Be diffuse across the scalp
Occur without smooth bald patches
Settle toward the person’s previous baseline
Occur without progressive widening of the part or recession
Leave the scalp free of significant pain, burning or inflammation

Signs that may indicate something other than seasonal shedding include:

A widening central part
Progressive recession at the temples or hairline
A decrease in ponytail circumference
Smooth or sharply defined areas of hair loss
Broken hairs of different lengths
Scalp pain, burning, marked itching or scale
Loss of eyebrows or body hair
Continued reduction in density

Seasonal shedding and another hair condition can occur at the same time. A seasonal pattern should not be used to dismiss progressive changes.

Seasonal Shedding Versus Hair Loss: Key Differences

Feature	More consistent with seasonal shedding	More reason to seek evaluation
Distribution	Diffuse shedding across the scalp	Focal patches, asymmetry, patterned thinning or hairline recession
Course	Temporary increase that settles toward the usual baseline	Persistent, progressively heavier shedding or continued loss of density
Visible density	No progressive widening of the part or recession	Widening part, smaller ponytail circumference or visible scalp progression
Scalp findings	No significant pain, burning, inflammation or heavy scale	Pain, burning, marked itching, inflammation, scale or signs of scarring

For an overview of other contributors, see What Causes Hair Loss?

Why Is My Hair Shedding So Much?

A noticeable increase in shedding can have many causes. Common considerations include:

Febrile illness or significant infection
Surgery or hospitalization
Major psychological or physiologic stress
Pregnancy and the postpartum period
Rapid weight loss or inadequate protein intake
Iron or other nutritional deficiencies
Thyroid dysfunction
Medication changes
Starting or stopping hormonal medications
Chronic inflammatory scalp conditions
Female- or male-pattern hair loss

Telogen effluvium often becomes noticeable approximately two to three months after a physiologic trigger. The relevant event may therefore not be immediately obvious when shedding begins.

A careful timeline is usually more valuable than assuming the most recent change in weather is responsible.

What Can You Do During Increased Hair Shedding?

There is no evidence-based way to stop normal seasonal shedding immediately. The goal is to protect the scalp and existing hair while determining whether another cause is present.

Continue Gentle, Regular Cleansing

Washing does not cause hairs to enter the shedding phase. It releases hairs that have already completed their attachment cycle.

Choose a cleansing frequency that keeps the scalp comfortable without causing excessive dryness. Avoid vigorous scratching or pulling during washing and detangling.

Protect the Hair Shaft

Limit repeated high-temperature styling, aggressive detangling and hairstyles that place sustained tension on the roots.

These measures will not change telogen biology, but they can reduce avoidable breakage and traction. This distinction matters because breakage and shedding require different approaches.

Support the Scalp Barrier

Choose scalp products according to scalp condition rather than shedding alone. A dry or sensitive scalp may benefit from gentle cleansing and lightweight hydration. An oily scalp or one with significant buildup may require more regular cleansing.

Scalp care can support cleanliness, hydration and comfort. It cannot correct thyroid disease, nutritional deficiency, telogen effluvium or patterned hair loss.

For more guidance, see How to Support a Healthy Scalp.

Maintain Adequate Nutrition

Hair-matrix cells are highly active during anagen. Adequate protein, iron, zinc and other micronutrients are necessary for normal follicular function.

More is not necessarily better. Supplements are most appropriate when they address dietary insufficiency, increased nutritional needs or a documented deficiency. Excessive supplementation can be ineffective and, in some cases, harmful.

Review the Previous Several Months

If shedding has increased, consider health events from approximately two to three months earlier, including illness, surgery, childbirth, major stress, rapid dietary change or a new medication.

This delay is characteristic of many cases of telogen effluvium.

A Physician’s Perspective

Seasonal shedding is a reasonable possibility when the pattern is diffuse, temporary and unaccompanied by progressive loss of density. It should remain a diagnosis of context rather than an automatic explanation for every increase in hair fall.

The most useful questions are:

Is this truly different from your usual baseline?
Is the hair being released from the root, or is it breaking along the shaft?
Has overall density changed?
Is the pattern diffuse, focal or concentrated along the part and hairline?
Was there an illness, surgery, pregnancy, medication change or nutritional stress several months earlier?
Are there scalp symptoms or other systemic symptoms?

Photographs taken under consistent lighting and with the same part placement can be more informative than repeatedly counting shed hairs.

When Should Hair Shedding Be Evaluated?

Consider medical evaluation when:

Shedding persists or continues to increase
There is visible loss of density
The central part is widening
Hair loss is focal, sharply defined or asymmetric
The scalp is painful, inflamed, heavily scaled or scarred
Shedding follows a new medication or significant health change
There are symptoms suggesting anemia, thyroid disease or another systemic condition
Hair loss is causing substantial concern, even if the pattern is uncertain

Evaluation may include a medical history, scalp examination, hair-pull testing, dermoscopy and targeted laboratory testing based on the clinical picture.

Supporting the Scalp and Hair During Seasonal Changes

Origenere approaches periods of increased shedding by supporting the conditions surrounding the follicle while recognizing the limits of cosmetic hair care.

A gentle shampoo and conditioner can help protect the hair shaft during cleansing. The Naturale Collection is designed for sensitive or thinning hair and scalp needs, while the Sempre Hair Growth Collection supports a consistent, comprehensive hair-care routine.

These products are not treatments for unexplained excessive shedding or an underlying medical disorder. Persistent or progressive hair loss should be evaluated rather than managed with cosmetic products alone.

Frequently Asked Questions

Is seasonal hair shedding real?

Human studies have found seasonal variation in the proportion of scalp hairs in the resting phase. The effect does not occur identically in every person, and its precise cause remains uncertain.

Does hair shed more in fall?

Some people notice more shedding as summer transitions into fall. Human studies have identified a summer peak in telogen hairs, which may be followed by visible release later in summer or during fall.

When is hair shedding season?

There is no universal season. Late summer and fall are commonly reported, and some research has identified a smaller spring fluctuation.

How long does seasonal hair shedding last?

Research has not established a standard duration. A temporary increase may settle as hair cycling becomes less synchronized, but continued or progressive shedding deserves evaluation.

How much hair shedding is normal?

There is substantial individual variation. Wash frequency, hair length, styling practices and a person’s baseline all affect what is visible. A persistent change from baseline or loss of density is more meaningful than one isolated count.

Does less daylight cause fall hair shedding?

Changing daylight is a biologically plausible influence on seasonal signaling, but a direct causal relationship has not been demonstrated in human scalp follicles.

Does seasonal shedding occur in women and men?

Seasonal changes have been reported in studies involving both men and women. The available studies do not show that every person will experience a noticeable seasonal pattern.

Does hair grow back after seasonal shedding?

If shedding reflects a temporary shift in otherwise healthy follicles, subsequent anagen growth would be expected. Regrowth should not be assumed when density continues to decline or another hair condition is present.

How can I stop seasonal hair shedding?

Normal hair release cannot be stopped immediately with a shampoo, supplement or scalp treatment. Gentle care, adequate nutrition and evaluation of persistent or atypical shedding are more appropriate than aggressive intervention.

The Bottom Line

Seasonal variation in human hair shedding is supported by observational research, particularly studies identifying increased telogen hairs during summer. The exact mechanism remains unresolved.

The biological clock within the hair follicle provides an intriguing direction for research, but it does not yet prove that shorter days or circadian disruption cause fall shedding.

A temporary, diffuse increase may reflect normal seasonal variation. Persistent shedding, progressive thinning, focal loss or scalp symptoms deserve a broader medical evaluation.

Sources

Randall VA, Ebling FJG. Seasonal changes in human hair growth. British Journal of Dermatology. 1991;124(2):146–151. View the study on PubMed.

Kunz M, Seifert B, Trüeb RM. Seasonality of hair shedding in healthy women complaining of hair loss. Dermatology. 2009;219(2):105–110. View the study on PubMed.

Al-Nuaimi Y, Hardman JA, Bíró T, et al. A meeting of two chronobiological systems: circadian proteins Period1 and BMAL1 modulate the human hair cycle clock. Journal of Investigative Dermatology. 2014;134(3):610–619. View the study.

Lin KK, Kumar V, Geyfman M, et al. Circadian clock genes contribute to the regulation of hair follicle cycling. PLOS Genetics. 2009;5(7):e1000573. View the study in PLOS Genetics.

Hardman JA, Haslam IS, Farjo N, Farjo B, Paus R. Thyroxine differentially modulates the peripheral clock: lessons from the human hair follicle. PLOS ONE. 2015;10(3):e0121878. View the study in PLOS ONE.