Why Is My Hair Becoming Thin and Dry? Hormonal Causes in Men & Women

Couples checking for hair thinning and dry hair

June 24, 2026

Why Hair Becomes Thin and Dry During Hormonal Changes

What thinning, shedding and dryness are really telling you and when it’s worth looking deeper

Hair is often one of the first places the body shows that something internally has shifted. In the clinic, I see this constantly: a patient comes in worried about thinning hair or a dry, brittle texture that won’t respond to a change of shampoo, and the conversation that follows is rarely just about hair. It’s about hormones, thyroid function, stress load, or nutrition.

This pattern shows up in both men and women, although the hormonal pathways driving it can differ. Understanding why hair changes happen matters because hair health is frequently a visible marker of what’s happening elsewhere in the body, not an isolated cosmetic issue.

How Hormones Influence Hair Health

Hair follicles are remarkably sensitive to hormonal signalling. Several hormones play a direct role in how hair grows, how long it stays in its growth phase, and how it eventually thins or sheds:

Testosterone and DHT (dihydrotestosterone)
Oestrogen and progesterone, particularly in women
Thyroid hormones, which affect hair in all genders
Cortisol, the body’s primary stress hormone
Insulin and other metabolic hormones

When any of these fall out of balance, the normal hair growth cycle is disrupted, and that disruption is what patients eventually notice as thinning, shedding, or a change in texture.

Why Hair Becomes Thinner Over Time

1. DHT sensitivity

DHT is a derivative of testosterone, and in people who are genetically sensitive to it, DHT can gradually shrink hair follicles, a process called miniaturisation. It also shortens the active growth phase of each hair, so strands grow finer and more sparse over successive cycles, particularly around the crown and hairline.

This is the most common driver of pattern hair loss in men, but it also affects a significant number of women, especially from midlife onward. If you’re noticing this pattern, our hair loss treatment service covers the diagnostic and treatment options in more detail.

2. Hormonal decline with age

As the body ages, hormone levels shift in ways that directly affect hair density. In women, declining oestrogen reduces hair volume and density, while falling progesterone affects the stability of the growth cycle. These are exactly the changes that bring many of my patients in during perimenopause and menopause, often alongside other symptoms they hadn’t connected to their hair.

In men, testosterone changes over time, and a relative increase in DHT activity in sensitive areas of the scalp, alter follicle behaviour in a similar way.

3. Thyroid imbalance — an underdiagnosed cause

Thyroid hormones regulate metabolism and cellular regeneration, including the turnover of hair follicle cells. When thyroid function is even mildly out of range, the effects on hair are often disproportionate to how the patient otherwise feels.

Both an underactive thyroid and subclinical thyroid dysfunction, where blood tests are borderline rather than clearly abnormal, can produce diffuse thinning across the scalp, a noticeably dry or brittle texture, and slower regrowth after shedding. This is one of the most frequently missed causes of hair change because it doesn’t always show up on a basic screening panel.

4. Stress and cortisol overload

Chronic stress affects hair through several overlapping mechanisms. It can push a larger-than-usual proportion of hair into its shedding phase, a condition known as telogen effluvium, while also disrupting hormone balance more broadly and reducing nutrient delivery to the follicles.

The reassuring part is that this type of hair loss is usually temporary and self-resolving once the underlying stressor eases, typically within several months. It only becomes a longer-term concern when the stress itself is ongoing and unaddressed, which is why I always treat stress-related shedding as a signal to look at the whole picture rather than just the hair.

5. Metabolic and nutritional factors

Hair is one of the first tissues in the body to reflect a nutritional shortfall, partly because the body deprioritises hair growth when resources are limited elsewhere. The factors I see most often in the clinic include:

Low iron or ferritin levels
Vitamin D deficiency
Insufficient protein intake
Insulin resistance
Poor gut absorption of key nutrients

These factors affect men and women equally, and they’re closely tied to broader metabolic health. In fact, the relationship between weight changes and hair loss is significant enough that I’ve written about it separately in our weight gain and hair loss hormonal connection guide, which is worth reading if you’ve noticed both changes together.

Why Hair Becomes Dry and Brittle

Dryness is often dismissed as a purely cosmetic concern, but it usually reflects something happening at the level of the follicle and scalp, not just the hair shaft itself.

Reduced sebum production

Ageing and hormonal shifts, particularly falling oestrogen, reduce the scalp’s natural oil output, leaving hair without the lubrication it needs to stay supple.

Structural changes in keratin

Hormonal and nutritional imbalances affect the quality of the keratin protein that makes up each strand, which can make hair feel rougher, weaker, or more prone to breakage.

Reduced hydration retention

As the hair shaft’s structure changes, it becomes less able to hold onto moisture, so it loses elasticity and starts to feel persistently dry even with consistent conditioning.

Environmental and lifestyle stress

Heat styling, pollution, and chronic stress all compound the underlying hormonal picture, accelerating dryness on top of whatever internal changes are already taking place.

Signs That Hair Changes May Be Hormonal or Medical

Not every bad hair day needs a clinical work-up, but certain patterns are worth paying attention to:

Gradual thinning that progresses over months or years
A receding hairline in men, or a visibly widening parting in women
Noticeably more hair coming out in the shower or on the brush
Hair that feels finer or weaker than it used to
Dry, brittle texture that doesn’t improve with better hair care
Fatigue, weight changes, or mood changes occurring alongside the hair changes

If several of these are present together, it’s a reasonable prompt to look at what’s happening hormonally and metabolically, rather than treating the hair in isolation.

Pattern Differences in Men and Women

In men

Hairline recession
Crown thinning
A strongly DHT-driven pattern

In women

Diffuse thinning spread across the scalp
Volume loss concentrated at the crown and parting
A close link to hormonal fluctuation, especially around midlife

Despite the visible differences, the biological mechanisms behind these patterns overlap considerably, which is why the diagnostic approach in the clinic is similar even when the presentation looks different.

Hair Changes as an Internal Health Signal

In my practice, I encourage patients to think of hair changes as one of several early indicators the body can give, alongside fatigue, cycle changes, or shifts in mood. The conditions most commonly underlying these changes include:

Hormonal imbalance
Thyroid dysfunction
Metabolic stress, including insulin resistance
Nutritional deficiencies
Chronic, unresolved stress load

This is why I assess hair as part of a whole-body health picture rather than treating it as a standalone cosmetic complaint.

A Medical Approach to Hair Thinning and Dryness

A proper clinical assessment for hair changes typically includes a hormonal evaluation, thyroid function testing, a check of iron, ferritin and key vitamin levels, a review of medical and lifestyle history, and a pattern analysis of how and where the hair loss is occurring.

Root-cause correction

Hormonal balancing, where clinically appropriate
Thyroid management
Nutritional optimisation

Medical hair restoration

Where appropriate, treatment can include PRP (Platelet-Rich Plasma) therapy, scalp stimulation treatments, or other targeted medical therapies.

Lifestyle medicine approach

Stress management strategies
Sleep optimisation
Dietary support tailored to the underlying deficiency

Clinical insight: hair thinning and dryness are rarely caused by a single factor. In most cases, it’s a combination of hormonal, metabolic and environmental influences working together, which is exactly why generic shampoos or one-size-fits-all cosmetic treatments so often fail to deliver lasting improvement.

When to Seek Professional Advice

It’s worth booking a medical evaluation if any of the following apply to you:

Hair changes are persistent or getting progressively worse
You’re noticing visible thinning or shedding
You have other symptoms, such as fatigue or weight change, alongside the hair changes
Over-the-counter treatments haven’t made a difference

In my experience, earlier diagnosis consistently leads to better long-term outcomes, both for the hair itself and for whatever underlying issue is driving it.

A Clinical Perspective from Dr Sandar Hlaing

In clinical practice, hair changes are very often one of the earliest signs of an internal hormonal or metabolic imbalance, sometimes appearing before a patient notices anything else. That’s why I take a structured, medical approach to every patient who comes in with hair concerns, particularly when their symptoms overlap with menopause or perimenopause, androgen-related hair loss, thyroid conditions, or stress-related systemic changes.

If you’re navigating hormonal changes more broadly, you may also find it useful to read more about our approach to menopause and hormone health, or, where weight changes are part of the picture, our GLP-1 and weight management service.

Final Message

Hair thinning and dryness are not just aesthetic concerns. In most cases, they’re early biological signals of deeper changes taking place inside the body, whether that’s a hormonal shift, a thyroid issue, or a nutritional gap. Understanding the underlying cause is the first step toward a treatment that actually works, rather than another round of products that only address the surface.

Frequently Asked Questions

Can hormonal changes cause hair to become thin and dry?

Yes. Hormonal changes can affect the hair growth cycle, scalp health, and natural oil production. Fluctuations in hormones such as oestrogen, testosterone, thyroid hormones, and cortisol may lead to increased hair shedding, reduced hair density, and a drier, more brittle hair texture.

Why is my hair suddenly becoming thinner?

Sudden hair thinning can be caused by several factors including hormonal changes, stress, thyroid disorders, nutritional deficiencies, illness, rapid weight loss, or certain medications. A medical assessment can help identify the underlying cause and guide appropriate treatment.

Does menopause cause hair thinning?

Many women notice changes in their hair during perimenopause and menopause. Falling oestrogen levels can reduce hair density and volume, while hormonal shifts may also contribute to dryness, increased shedding, and slower hair growth.

Can men experience hormonal hair loss too?

Absolutely. Hormonal hair loss affects both men and women. In men, sensitivity to dihydrotestosterone (DHT) is one of the most common causes of male pattern hair loss. Hormonal, metabolic, and lifestyle factors can also contribute to hair thinning.

Can thyroid problems affect hair quality?

Yes. Both underactive and overactive thyroid conditions can affect hair growth and texture. Many people with thyroid disorders experience diffuse hair thinning, increased shedding, dry hair, and slower regrowth.

Can hair thinning caused by hormones be reversed?

In many cases, hair thinning can improve when the underlying cause is identified and treated. Outcomes depend on factors such as the cause, duration of symptoms, and individual response to treatment. Early assessment generally provides the best opportunity for improvement.