19 July, 2026 | Abdul Jabbar - MPharm
She notices it first in the shower. More strands than usual, caught between her fingers, gathering around the drain. Then on her pillow. Then in the hairbrush, in a way that feels different from before, though she can't immediately say why.
She tells herself it's nothing. Everyone loses hair. But she starts checking, more than she used to, and the checking itself becomes part of the problem: a low, persistent worry running underneath an ordinary day.
Hair loss in women is remarkably common. Some estimates suggest that up to half of women will experience noticeable thinning at some point in their lives.(1) And yet it remains something many women feel oddly alone with, partly because hair loss is culturally coded as a male experience, and partly because the causes in women are more varied and less visible than the classic receding hairline most people picture.
The good news is that women's hair loss is generally well understood clinically, even where it isn't well understood publicly. Most causes have a name, a reason, and in many cases, an effective way to manage it. In this article I want to walk through what those causes actually are, how hair loss in women is diagnosed, what treatments genuinely help, and when it's worth seeking a clinical opinion.
Before looking at causes of hair loss, it helps to know what's normal. Hair grows in cycles, and at any given time roughly ninety percent of scalp hair is in an active growth phase, while the remaining ten percent is in a resting phase before it sheds to make way for new growth. Losing somewhere between fifty and one hundred hairs a day is a normal part of that cycle, not a sign that anything is wrong.
What isn't part of the normal cycle is a noticeable change: shedding that is clearly heavier than usual, thinning that is visible in the mirror or in photographs, a widening parting, or patches where hair has come away in a defined area. These patterns are worth paying attention to, and understanding which pattern you're seeing is usually the first step toward identifying the cause.
Female pattern hair loss, also known as androgenetic alopecia, is the most common cause of hair thinning in women, and it is fundamentally different in presentation from the pattern usually seen in men. Rather than a receding hairline or bald patches, it typically causes a gradual, diffuse thinning that is most visible at the crown and along the centre parting, which often appears to widen over time.(1)
The underlying mechanism involves a genetic sensitivity in certain hair follicles to androgens (a group of hormones that includes testosterone), which causes the growth phase of affected follicles to shorten progressively over successive cycles. Each new hair that grows is finer and shorter than the last, until eventually some follicles stop producing visible hair altogether.(1,5) It tends to run in families, can begin at any point after puberty, and often becomes more noticeable around and after menopause as hormone levels shift.
Telogen effluvium describes a temporary but often alarming form of diffuse hair shedding, in which a stressor pushes a much larger proportion of hair follicles than usual into the resting phase simultaneously. Because hair takes around two to three months to move from the resting phase to actually shedding, the hair loss is often noticed well after the triggering event, which can make the cause hard to identify without a careful history.(2)
Common triggers include significant illness, surgery, high fever, rapid weight loss, crash dieting, major surgery, and periods of intense emotional or psychological stress.(2,8) Childbirth is one of the most frequent triggers and is common enough to be considered its own category (see below). In most cases, telogen effluvium resolves on its own within six to nine months of the triggering event, once the underlying cause has passed and the hair cycle re-establishes its normal rhythm.
During pregnancy, elevated oestrogen levels extend the growth phase of hair follicles, which is part of why many women notice thicker, fuller hair while pregnant. After childbirth, oestrogen levels fall sharply, and the hair that had its shedding delayed during pregnancy is released all at once. This usually becomes noticeable two to four months after delivery and can feel dramatic, but it is a well-recognised, temporary variant of telogen effluvium that typically resolves within six to twelve months.(2)
If you're noticing unexpected hair shedding and aren't sure what's behind it, it's worth talking it through with a clinician rather than guessing. At iQ Doctor our clinical team can help you understand what's happening and what, if anything, needs further investigation.
Beyond female pattern hair loss and stress-related shedding, several hormonal and medical conditions are well-established causes of hair thinning in women, and identifying them matters because treating the underlying cause is often the most effective route to improvement.
Thyroid dysfunction
The thyroid gland plays a direct role in regulating the hair growth cycle, and thyroid hormone receptors are present in the hair follicle itself.(4) Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can cause diffuse hair thinning, often alongside other symptoms such as fatigue, weight changes, temperature sensitivity or changes in mood. A simple blood test (thyroid function tests) can identify or rule this out as a contributing factor.
Iron deficiency
Low iron stores are one of the most common and most overlooked causes of hair thinning in women, particularly those with heavy periods, a plant-based diet, or a history of blood loss. Research has shown that hair follicles are sensitive to iron levels even before those levels are low enough to cause conventional anaemia, which is why ferritin (a measure of stored iron) is usually tested specifically rather than relying on a standard blood count alone.(3)
Polycystic ovary syndrome (PCOS)
PCOS is a hormonal condition affecting how the ovaries function, and it is associated with higher circulating levels of androgens. In some women this manifests as hair thinning on the scalp, following a similar pattern to female pattern hair loss, sometimes alongside other symptoms such as irregular periods, acne or increased facial or body hair.(5) Because the hair changes in PCOS overlap with female pattern hair loss, an accurate diagnosis usually depends on the wider clinical picture rather than the hair alone.
Menopause
The hormonal shifts of perimenopause and menopause, particularly the decline in oestrogen relative to androgens, can cause or accelerate hair thinning that closely resembles female pattern hair loss. This is one of the reasons hair thinning is so commonly reported by women in their forties and fifties, and why it is often addressed as part of a broader conversation about menopausal symptoms and hormone health rather than in isolation.
Alopecia areata
Alopecia areata is an autoimmune condition in which the immune system mistakenly attacks hair follicles, typically causing sudden, well-defined round or oval patches of hair loss rather than diffuse thinning. It can affect anyone at any age and its course is unpredictable: some people experience a single episode with full regrowth, while others have recurring or more extensive patches.(6) Because it has a different underlying mechanism to female pattern hair loss or telogen effluvium, it usually benefits from a specific dermatological assessment.
Traction alopecia
Traction alopecia results from prolonged tension on the hair follicles, most often from tightly pulled hairstyles such as tight ponytails, braids, buns or hair extensions worn consistently over long periods. It typically appears first along the hairline or wherever tension is greatest, and it is one of the few causes of hair loss that can usually be prevented or halted early by changing hairstyling habits, though longstanding traction can eventually cause permanent follicle damage.
"The women I see with hair loss have often been carrying this quietly for months, sometimes years, before they raise it. There's a tendency to assume it's just stress, or just ageing, or just something to live with. Very often there's an identifiable and manageable cause underneath it, and finding that out changes the entire conversation from worry to a plan."
Omar El-Gohary, Superintendent Pharmacist, iQ Doctor
Getting to an accurate diagnosis usually starts with a detailed history: when the shedding or thinning started, whether it's diffuse or patchy, any recent illnesses, medication changes, weight changes, menstrual history, family history of hair loss, and any accompanying symptoms. This history alone often narrows down the likely cause considerably.
From there, a clinician will usually examine the scalp and the pattern of hair loss directly, since the distribution (diffuse thinning versus a defined patch versus hairline recession) is one of the most useful diagnostic clues. Blood tests are commonly used to check thyroid function, iron and ferritin levels, and sometimes hormone levels, particularly where PCOS is suspected. In cases where the diagnosis remains unclear, a dermatologist may recommend a scalp biopsy, though this is relatively uncommon and reserved for cases that don't fit a clear clinical pattern.
Treatment depends entirely on the underlying cause, which is why an accurate diagnosis matters more than reaching for a generic hair loss product. That said, several evidence-based options are widely used and, for many women, genuinely effective.
Topical minoxidil
Minoxidil, applied directly to the scalp, is the most established treatment for female pattern hair loss and is licensed for use in women.(1,7) It works by prolonging the growth phase of hair follicles and increasing blood flow to the scalp, though the exact mechanism isn't fully understood. It requires realistic expectations: most women need at least three to six months of consistent daily use before seeing any visible improvement, and the effect is generally maintained only for as long as treatment continues.
Addressing the underlying cause
Where hair loss is linked to iron deficiency, thyroid dysfunction, or PCOS, treating that underlying condition, whether through iron supplementation, thyroid medication, or hormonal management, is often the most effective route to improvement, sometimes alongside topical treatment. This is why a proper diagnostic work-up matters before committing to a specific treatment.
Lifestyle and hair care measures
Other options
For some women, other prescription treatments, hormonal approaches, or referral to a dermatologist for conditions such as alopecia areata may be appropriate. These decisions are individual and depend on the diagnosis, medical history and personal preference, which is why they're best discussed directly with a clinician rather than self-selected from general information online.
iQ Doctor's clinical team can talk you through appropriate hair loss treatment options based on your history, including topical minoxidil, and can advise on further investigation where needed.
Hair loss doesn't always need an urgent medical appointment, but certain features make a clinical review worthwhile sooner rather than later:
None of these on their own means something serious is happening. But they are all good reasons to have the pattern properly assessed rather than guessing, because the right treatment depends entirely on identifying the right cause.
Ready to get some answers about your hair loss?
If hair loss has been on your mind, whether it's new, gradual, or something you've been quietly managing for a while, iQ Doctor's UK-registered clinical team offers confidential consultations to help you understand what's happening and what can help.
The following questions are answered with reference to current clinical understanding. If you have specific concerns about your health, please speak to a qualified healthcare professional.
The most common causes are female pattern hair loss (a genetic, hormone-related thinning), telogen effluvium (temporary shedding triggered by stress, illness or hormonal change), postpartum hair loss, thyroid dysfunction, iron deficiency and polycystic ovary syndrome (PCOS). Many women experience more than one contributing factor at the same time, which is why an accurate diagnosis matters before starting treatment.(1,2,5)
Female pattern hair loss causes gradual thinning, most noticeably at the crown and along the centre parting, rather than the receding hairline and balding patches typically seen in men. It is driven by a combination of genetics and androgen sensitivity in the hair follicles, and it usually progresses slowly over years rather than months.(1)
Yes. Significant physical or emotional stress can push a larger-than-usual proportion of hair follicles into the shedding phase of the growth cycle, a condition called telogen effluvium. The shedding is usually noticed two to three months after the triggering event and, in most cases, resolves on its own once the underlying stressor has passed.(2,8)
It's possible. Both an underactive and an overactive thyroid can disrupt the hair growth cycle, and low iron stores (measured as ferritin) are a well-established cause of diffuse hair thinning in women, even before iron levels are low enough to cause anaemia. A simple blood test can check both.(3,4)
Yes, postpartum hair loss is extremely common and considered a normal variant of telogen effluvium, triggered by the sharp drop in oestrogen after childbirth. It typically starts two to four months after delivery and resolves within six to twelve months as the hair cycle returns to normal, though for some women it takes a little longer.(2)
Telogen effluvium is a temporary, diffuse form of hair shedding that happens when a stressor, whether physical (illness, surgery, rapid weight loss) or emotional, causes more hair follicles than usual to enter the resting (telogen) phase at the same time. It typically presents as increased shedding all over the scalp rather than a specific bald patch, and it is usually reversible.(2)
Topical minoxidil is the most established and widely used treatment, and is licensed for use in women. Addressing any underlying contributing factor, such as low iron or thyroid dysfunction, is equally important. For some women, other prescription options may be appropriate and can be discussed as part of a clinical consultation. Realistic expectations and consistent use matter: minoxidil typically needs at least three to six months of regular use before benefits are visible.(1,7)
It's worth seeking a clinical review if your hair loss is sudden or rapid, appears in distinct patches, is accompanied by scalp itching, redness or pain, or comes with other symptoms such as fatigue, irregular periods or changes in weight. Gradual thinning is also worth discussing with a clinician, both to identify the cause and to understand which treatments are likely to help.(3,4,5,6)
CEO & Superintendent Pharmacist, iQ Doctor - Registration Number 2059792.
Omar is passionate about developing healthcare technology to empower our patients.