Beauty

Hair loss in women: shedding, pattern loss and what helps

Shedding 50 to 100 hairs a day is normal, and at any moment about 85 percent of scalp hair is growing while about 15 percent rests. Two patterns account for most hair loss in women: telogen effluvium is a diffuse shed that starts roughly 3 months after an illness, an operation, a birth or a crash diet, with a range of 1 to 6 months, and the acute form lasts under 6 months. Female pattern hair loss is slower and progressive rather than self limiting: about 12 percent of women show it by 29, 25 percent by 50 and 41 to 50 percent at 70 and over. Sudden loss, patchy loss, a scarred scalp, or loss with itching, burning or pain is a different problem and belongs with a doctor rather than a shampoo.

What normal shedding looks like

At any moment on a healthy scalp, about 85 percent of hairs are in the growing phase and about 15 percent are resting, with a few in the short transition phase between the two. A single follicle produces a growing hair for almost 4 years, rests for about 4 months, and then pushes the old hair out as the new one comes through. Shedding is the mechanism working rather than failing. The NHS puts ordinary loss at 50 to 100 hairs a day, most of it unnoticed.

Collecting 100 or more hairs in 24 hours points towards telogen effluvium rather than normal turnover. Under sustained physical stress, roughly 70 percent of growing hairs can be tipped into the resting phase at once, and because a resting hair stays in place for about 4 months, they leave together months later instead of on the day the stress happened.

Volume is a poor witness on its own, since hair reads as thinner when it is wet and nobody measured the ponytail beforehand. Two photographs of the same parting in the same light, 8 weeks apart, beat an estimate of what is in the plughole.

Telogen effluvium and the three month delay

Telogen effluvium is a diffuse shed, not a bald patch. The triggers are familiar: a feverish illness or severe infection, major surgery, serious injury, childbirth and the fall in oestrogen that follows it, an underactive thyroid, stopping an oestrogen containing medicine, crash dieting, low protein intake and iron deficiency. Medicines have their own list, headed by beta blockers, retinoids including excess vitamin A, anticoagulants, propylthiouracil, carbamazepine and, occasionally, vaccinations.

The causative event sits roughly 3 months before the shedding starts, with a range of 1 to 6 months, so by the time hair is coming out in the shower the illness has often been forgotten. Acute telogen effluvium is defined by lasting less than 6 months and is self limiting once the cause has gone or been corrected. Growth may take up to 6 months to restart, and longer again before anyone but you can see it.

Washing and brushing are not the problem, and stopping them changes nothing: the hairs coming away have already finished their cycle. A pull test is worth doing while the shed is happening rather than 3 months afterwards. Shedding still going at 6 months is the chronic form, and a reason to be examined rather than to buy something stronger.

Pattern hair loss behaves differently

Female pattern hair loss works differently. The follicles miniaturise, producing finer and shorter hairs over years, and the thinning is central rather than patchy. What women notice first is a widening parting, a ponytail that needs an extra turn of the band, and sometimes recession at the temples. It is progressive, so the realistic aim of treatment is to slow it and hold what is there.

It is not only a condition of later life. Prevalence rises steadily with age: about 12 percent of women by 29, 25 percent by 50, and 41 to 50 percent at 70 and over. The American Academy of Dermatology puts the usual onset in the 40s, 50s or 60s, with earlier starts in some women, and describes continuous loss that rarely goes as far as total baldness.

Genetics do most of the work, inherited from either parent or both. Endocrine conditions raise the risk, including polycystic ovary syndrome, congenital adrenal hyperplasia and, rarely, ovarian or adrenal tumours. Signs worth reporting at the appointment: irregular periods, new coarse facial hair, and acne that has arrived or worsened in adult life, which our guide on adult acne after 25 sets out. Pattern loss also carries a psychological cost, and screening for anxiety and depression belongs in the consultation rather than after it.

How a diagnosis is actually made

The diagnosis is clinical: a history and a proper look at the scalp, not a laboratory panel. The hair pull test is the bedside step. A bundle of hair is grasped close to the scalp and drawn gently along the shaft, and the hairs that come away are counted. Thresholds differ: at least 4 hairs with each pull marks an active telogen shed, while a 2026 clinical review calls the test positive at 6 or more. In pattern hair loss the test is usually negative, or positive only over the central scalp.

Blood tests are targeted rather than routine. Ferritin and thyroid stimulating hormone are the two that earn their place when another cause is suspected, and a thyroid test is warranted when tiredness, constipation, weight gain or sensitivity to cold come with the hair loss. Ferritin has to be read with care: a low result confirms iron deficiency, a normal result does not exclude it because ferritin rises with inflammation, and iron saturation is the more sensitive indicator. Androgen levels are usually normal and not helpful unless there are signs of excess androgen.

A scalp biopsy is not usually indicated. Where one is taken during active shedding, finding between 25 and 50 percent of follicles in the resting phase confirms telogen effluvium. Referral to a dermatologist is the right step when the diagnosis is unclear, when a scarring alopecia has to be excluded, or when itching, burning or pain comes with the loss. Sudden loss, patchy or circular bald areas, and a smooth shiny area where the follicle openings have disappeared all belong in that group. The NHS advice is to see a general practitioner before booking a commercial hair clinic, and our checklist for choosing a practitioner applies to hair clinics too.

What treatment can and cannot do

Topical minoxidil is the first line drug treatment for pattern hair loss and the one the NHS lists for both sexes. It is used as a 2 percent solution twice daily or a 5 percent foam once daily. Response takes 6 to 12 months, and a transient increase in shedding in the first weeks is expected rather than a sign of failure. Side effects are real: an irritated scalp with dryness, scaling, itching or redness is the common one, and hair can start growing where it is not wanted, on the cheeks or forehead. In a randomised trial the mean benefit of 5 percent topical minoxidil was 42 out of 100 on an investigator rated visual analogue scale, which reads as moderate improvement rather than restoration.

Minoxidil works only for as long as it is used, and it does not work for everyone: the American Academy of Dermatology treats no growth within 12 months as the point at which a medicine will not work for you. Most hair loss treatments are not available on the NHS, so the cost sits with you. Oral spironolactone, up to 100 mg twice daily, is the other first line option, and a systematic review of it on its own found increased hair density in 43 percent of users; it is a prescription medicine, so that route starts with a doctor. Pregnancy and breastfeeding change the answer: minoxidil is avoided if you are pregnant, planning a pregnancy or breastfeeding, and most drug treatments for hair loss are contraindicated in pregnancy.

Supplements are not the general answer they are sold as. A 2017 review of diet and hair loss found no clinical trials showing that biotin helps hair loss in the absence of a deficiency, judged the evidence insufficient to recommend iron to everyone with hair loss and iron deficiency without anaemia, and noted that data on vitamin D supplementation in hair loss is lacking. Wasted money is the smaller risk: selenium toxicity from nutritional supplements is well documented and can cause generalised hair loss, and high vitamin A has a known link to hair loss as well. Correct a deficiency shown on a test, and treat the rest of the shelf with suspicion.

Signs that belong with a doctor rather than a shampoo

Frequently asked

How many hairs a day is too many?

The NHS puts normal loss at 50 to 100 hairs a day. Collecting 100 or more hairs in 24 hours points towards telogen effluvium, and during an active shed a gentle pull test removes at least 4 hairs each time.

Why did my hair start falling out months after I was ill?

That delay is the rule rather than the exception. The causative event usually sits about 3 months before the shedding starts, with a range of 1 to 6 months, because the affected hairs have to finish their resting phase before they are pushed out.

Will the hair come back after telogen effluvium?

Acute telogen effluvium lasts under 6 months and is self limiting once the trigger has gone or been corrected, and recovery of hair density is the usual outcome. Growth may take up to 6 months to restart, and longer again before it is visible, so no honest timetable can be put on the mirror.

Do I need blood tests?

Not routinely. Ferritin and thyroid stimulating hormone are the tests that usually earn their place when another cause is suspected, androgen levels are normally unhelpful unless there are signs of excess androgen, and a scalp biopsy is not usually indicated.

Do supplements help with hair loss?

Only where a deficiency has been shown. A 2017 review found no clinical trials supporting biotin without a deficiency and insufficient evidence to give iron to everyone with hair loss and iron deficiency without anaemia, and it recorded that selenium toxicity from supplements can cause generalised hair loss and that high vitamin A is linked to hair loss too.

How long before minoxidil can be judged?

6 to 12 months, with a transient increase in shedding in the first weeks and an irritated scalp as the common side effect. It works only while it is used, it does not work for everyone, and no growth within 12 months is the point at which it is treated as ineffective for that person. Avoid it if you are pregnant, planning a pregnancy or breastfeeding.

Sources

• NHS, Hair loss · United Kingdom health service page. Source of normal loss at 50 to 100 hairs a day, the advice to see a general practitioner before going to a commercial hair clinic, minoxidil as the medicine listed for male and female pattern baldness, and the statements that treatments do not work for everyone, work only for as long as they are used and are mostly not available on the NHS.
• Telogen effluvium, StatPearls, NCBI Bookshelf · Peer reviewed clinical reference. Source of about 85 percent anagen and 15 percent telogen hair, almost 4 years of growth and about 4 months of rest, roughly 70 percent of anagen hair shifting under sustained stress, the trigger and medicine lists, the causative event about 3 months before the shed with a range of 1 to 6 months, acute shedding lasting less than 6 months, at least 4 hairs on a pull test during the shed, 100 or more hairs in 24 hours, 25 to 50 percent of follicles in telogen on biopsy, the thyroid and iron testing advice with ferritin and iron saturation, and growth taking up to 6 months to restart.
• Female pattern hair loss, CMAJ, 2026 · Five minute clinical review in a major general medical journal. Source of prevalence at 12 percent by 29, 25 percent by 50 and 41 to 50 percent at 70 and over, the hair pull test threshold of 6 or more hairs, ferritin and thyroid stimulating hormone as the targeted tests, androgen levels usually normal and not helpful, scalp biopsy not usually indicated, referral when the diagnosis is unclear, to exclude scarring alopecia or when itching, burning or pain accompany the loss, 2 percent minoxidil solution twice daily or 5 percent foam once daily, 6 to 12 months to response with transient early shedding, the mean benefit of 42 out of 100 on a visual analogue scale, spironolactone up to 100 mg twice daily with a systematic review of the drug on its own showing increased hair density in 43 percent of users, the endocrine risk factors, and the pregnancy contraindications.
• American Academy of Dermatology, Female pattern hair loss · Patient information from a dermatology body. Source of the usual onset in the 40s, 50s or 60s with earlier starts in some women, the inherited basis from either parent, the description of continuous loss that rarely becomes total baldness, minoxidil in 2 and 5 percent strengths, 6 to 12 months of daily use before results, the statement that no hair growth within 12 months means the medicine will not work for that person, the side effects of scalp irritation and hair growth on the cheeks or forehead, and the advice that women who are pregnant, planning a pregnancy or breastfeeding should avoid minoxidil.
• Diet and hair loss, effects of nutrient deficiency and supplement use, Dermatology Practical and Conceptual, 2017 · Open access review of nutrition and hair. Source of the finding that no clinical trials show biotin helps hair loss without a deficiency, that the evidence is insufficient to recommend iron to all hair loss patients with iron deficiency in the absence of anaemia, that data on vitamin D supplementation in hair loss is lacking, and that selenium toxicity from nutritional supplements causes generalised hair loss while high vitamin A is linked to hair loss.

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This guide is for general information. It does not replace advice from a dermatologist, physician or qualified practitioner, or an examination.