Hair loss in women is most often caused by female pattern hair loss, an inherited condition that causes gradual thinning, usually seen as a widening parting. The other very common cause is temporary shedding (telogen effluvium) a few months after a trigger such as childbirth, illness, major stress or crash dieting, which usually recovers on its own. Thyroid problems, low iron and other deficiencies, tight hairstyles and some medicines can also play a part. The most widely recommended treatment for pattern hair loss is minoxidil applied to the scalp, but the first step is to see a doctor or dermatologist to find the cause, because many causes are treatable.
Finding more hair in your brush can be worrying. This guide explains what is normal, the main causes of hair loss in women, how doctors diagnose it, what treatments the evidence supports, and what to be cautious about.
How much hair loss is normal?
Everyone sheds hair every day as part of the natural hair growth cycle. The NHS says losing between 50 and 100 hairs a day is normal, and it is often not noticed. It is worth getting checked if you are shedding noticeably more than usual, your parting is widening, you see patches of hair loss, or your scalp is itchy, sore or scaly.
Shedding or hair loss?
The American Academy of Dermatology (AAD) draws a helpful distinction. Excessive shedding (telogen effluvium) happens when more hairs than usual enter the resting phase and fall out together, usually a couple of months after a trigger; the hair normally grows back. Hair loss happens when something stops hair from growing, such as inherited pattern hair loss or damage to the follicles, and does not resolve without addressing the cause.
Common causes of hair loss in women
| Cause | What it typically looks like | Usually reversible? |
|---|---|---|
| Female pattern hair loss | Gradual thinning on top, widening parting | No, but treatment can slow it and sometimes regrow hair |
| Telogen effluvium (shedding) | Diffuse shedding a few months after a trigger | Yes, usually within months |
| Thyroid disease | Diffuse thinning, often with other symptoms | Often, once the thyroid is treated |
| Low iron, protein, zinc or biotin | Diffuse thinning | Often, once corrected |
| Traction alopecia | Thinning where hair is pulled tight, e.g. hairline | Early on; can become permanent |
| Alopecia areata | Round or oval bald patches | Varies; needs medical assessment |
Based on AAD information on causes of hair loss and the NHS hair loss page.
Female pattern hair loss
The AAD says female pattern hair loss is the most common cause of hair loss in women. It often begins in the 40s, 50s or 60s, although it can start earlier. Signs include a widening parting, thinning at the temples, and general thinning across the top of the head. It runs in families, and hormonal changes after the menopause may play a role. The NHS notes that pattern hair loss is permanent, so treatment aims to slow it and regain some density rather than cure it.
Telogen effluvium after childbirth, illness or stress
According to the AAD, triggers for excessive shedding include:
- giving birth
- losing a lot of weight (the AAD gives 20 pounds, about 9 kg, or more as an example)
- extreme stress
- a high fever, surgery or recovering from an illness
- stopping birth control pills
Shedding usually starts a few months after the trigger. After childbirth, the AAD says it often begins around two months and peaks around four months, and most women see their hair regain its normal fullness within 6 to 9 months.
Thyroid problems and nutrient deficiencies
The AAD lists thyroid disease and getting too little biotin, iron, protein or zinc among the causes of hair loss, and notes that hair often regrows once these are treated. Iron deficiency is also named by the NHS. If you also feel tired, cold or sluggish, ask your doctor about thyroid tests (see our guide to hypothyroidism symptoms and tests) and iron studies (see iron studies and ferritin explained).
Hormonal conditions and medicines
The AAD notes that hormonal imbalance, including polycystic ovary syndrome (PCOS), can cause thinning, and that some medicines can cause hair loss as a side effect. Do not stop a prescribed medicine on your own; ask your doctor whether it could be involved.
Hair care and hairstyles
Regular colouring, perming or relaxing can damage hair, and the AAD warns that tight ponytails, braids, buns or extensions can cause traction alopecia, which may become permanent if the pulling continues. Other causes the AAD lists include alopecia areata (an autoimmune condition), scalp infections, scalp psoriasis, scarring alopecias, cancer treatment and a hair-pulling disorder called trichotillomania.
How doctors diagnose hair loss
A doctor or dermatologist will usually ask when the hair loss started, about recent illness, childbirth, stress, weight loss, diet, periods, medicines and family history, and examine your scalp and hair pattern. Blood tests may be suggested to check things such as iron levels and thyroid function. A dermatologist may also look closely at the scalp and, occasionally, take a small skin sample. The NHS advises seeing a GP before paying for treatment at a commercial hair clinic.
Treatment options
Minoxidil
The AAD calls minoxidil, applied to the scalp in 2% or 5% strengths, the most recommended treatment for female pattern hair loss, and it is approved by the US FDA for this use. The NHS also lists it as an option. Things to know:
- You may notice extra shedding for the first 2 to 8 weeks, which usually settles.
- It takes 6 to 12 months to tell whether it is working.
- It only works while you keep using it.
- Possible side effects include scalp irritation and unwanted facial hair growth.
- The AAD advises against using it during pregnancy or breastfeeding.
Prescription tablets
Dermatologists sometimes prescribe tablets off-label, such as spironolactone. The AAD notes that such medicines can cause birth defects, so women who could become pregnant need reliable contraception, and that regrown hair is usually lost a few months after stopping. The NHS says finasteride should not be used by women. These are prescription-only decisions for a specialist.
Procedures and devices
The AAD mentions several other options: hair transplant surgery for suitable patients; FDA-cleared laser devices for home use, whose long-term safety is not yet known; and platelet-rich plasma (PRP) injections, which show early promise but need more research. Stem-cell treatments are experimental. If you are considering a procedure, see a board-certified dermatologist.
Treating the underlying cause
Where hair loss is caused by a thyroid problem, deficiency, a medicine or a hairstyle, treating that cause is usually the key step. Telogen effluvium normally recovers by itself once the trigger has passed.
Do supplements, shampoos and oils help?
Many products promise thicker hair, but the evidence is limited:
- Supplements: the AAD notes that studies of supplements such as biotin and folic acid have mostly found no benefit for female pattern hair loss, unless you are deficient. One study of 120 women found some benefit from a supplement combining omega-3 and omega-6 fatty acids with antioxidants, but more research is needed. Our biotin guide covers food sources and who may be low in it.
- Shampoos: the AAD says shampoos cannot regrow hair.
- Oils: scalp oiling can make hair feel softer and easier to manage, but there is no good evidence it treats pattern hair loss. See our practical guide to hair oiling.
Eating a balanced diet with enough protein and iron supports overall health, including hair, but it will not reverse inherited thinning on its own.
Gentle hair care while you wait
- Choose looser hairstyles and alternate them so the same area is not pulled every day.
- Limit chemical treatments and high heat.
- Be patient: most treatments take months, and new growth can take time to show.
- The NHS notes that wigs, hair pieces and counselling or support groups can help with the emotional impact of hair loss.
When to see a doctor
See a GP or dermatologist if you notice sudden or patchy hair loss, a widening parting, hair loss with an itchy, painful or scaly scalp, or hair loss with other symptoms such as tiredness, weight change, irregular periods or excess facial or body hair. Early assessment gives you the best chance with treatments that slow loss.
Frequently asked questions
Will my hair grow back after pregnancy?
Usually, yes. The AAD says shedding after childbirth is common and most women regain normal fullness within 6 to 9 months.
Can stress make my hair fall out?
Yes. Major stress is a recognised trigger for telogen effluvium. Shedding usually starts a few months later and recovers once the stress has passed.
How long does minoxidil take to work?
The AAD says it takes 6 to 12 months to judge results, and you need to keep using it to maintain them.
Should I take biotin for hair loss?
Only if a doctor finds you are deficient. Studies have mostly not shown a benefit otherwise, and the US FDA has warned that biotin supplements can interfere with some laboratory blood tests, so tell your doctor if you take it.
Is female pattern hair loss permanent?
The NHS describes pattern hair loss as permanent, but treatments like minoxidil can slow it and sometimes improve density while they are used.
Disclaimer: This article is for general information only and is not medical advice. Skin differs from person to person. Patch-test new products, and consult a dermatologist or doctor for persistent, painful or worsening skin problems, or before using active ingredients if you are pregnant, breastfeeding or on prescription treatment.
