Thinning hair in women is common and often has a cause that can be identified, such as low iron, a thyroid problem, a hormonal condition, recent illness or childbirth, or female pattern hair loss. The first step is not a treatment but a diagnosis: a doctor’s history, a scalp examination and, usually, a few targeted blood tests. That is why hair loss sits within our regenerative medicine service but always starts with medical assessment.
Is it thinning, shedding or patchy loss?
The pattern of hair loss is one of the most useful clues. Doctors broadly think about three types:
- Gradual thinning over the crown and parting, with the hairline at the front usually kept. This is typical of female pattern hair loss.
- Sudden, diffuse shedding, where much more hair than usual comes out in the shower or on the brush, all over the scalp. This is often telogen effluvium.
- Patchy loss, with smooth bald patches or areas where the scalp looks red, scaly or scarred. This needs a closer look sooner.
It is normal to lose up to around 100 hairs a day. It is the change from your usual pattern that matters.
What medical causes should be ruled out?
Low iron stores
Iron deficiency, with or without anaemia, is a common and treatable factor in women’s hair shedding, especially with heavy periods, pregnancy or a diet low in iron. Our article on heavy periods explains why these are worth looking into.
Thyroid problems
Both an underactive and an overactive thyroid can cause hair to thin. Other clues include tiredness, weight change, feeling cold or hot, and changes to periods.
Hormonal conditions
Polycystic ovary syndrome can cause thinning on the scalp alongside irregular periods, acne or extra hair growth on the face and body. Hormonal changes around perimenopause and menopause can also affect hair.
Telogen effluvium
A significant shock to the body can push many hairs into their resting phase at once. Shedding typically starts two to three months after the trigger, which can include childbirth, a high fever or serious illness, surgery, rapid weight loss, crash dieting or major stress. It usually settles by itself within about six months once the trigger has passed.
Medicines and other factors
Some medicines can cause hair shedding, as can starting or stopping hormonal contraception. Very low-calorie or low-protein diets, and some vitamin deficiencies, may contribute too.
Scalp and immune conditions
Alopecia areata, an autoimmune condition, causes patchy loss. Tight hairstyles can cause traction alopecia. Some less common inflammatory conditions cause scarring, where the hair follicle is permanently damaged.
Related readingHeavy periods: when to investigate, not just manageRead the article →What tests are usually worth doing?
Tests should be guided by your history rather than done as a large panel for everyone. Commonly useful tests include:
- A full blood count, to check for anaemia
- Ferritin, which reflects iron stores
- Thyroid function
- Vitamin D, B12 and folate in some people
- Hormone tests where there are signs of polycystic ovary syndrome or another hormonal cause
Many of these overlap with the tests in our guide to blood tests worth doing when you are always tired, because the causes often overlap too. Our private GP service can arrange them quickly.
What about female pattern hair loss?
Female pattern hair loss is the most common cause of gradual thinning in women. It tends to run in families, becomes more common with age, particularly after menopause, and is linked to how sensitive hair follicles are to hormones. It does not usually cause complete baldness.
It is a long-term condition, and treatments aim to slow thinning and, for some people, improve density. Options include topical treatments, prescription treatments that we can discuss at your appointment, and, for some people, PRP. There is some trial evidence for a modest benefit from PRP in pattern hair loss, but results vary and it is not right for everyone. Our article on regenerative medicine, explained honestly covers the evidence in more detail. Any treatment usually needs several months before you can judge whether it is working. You can also read more on our hair thinning page.
When to see a doctor sooner
Please see a doctor promptly, through your NHS GP or with us, if:
- Hair is falling out in patches or clumps
- Your scalp is red, scaly, itchy, burning or painful, or looks scarred or shiny, as some scarring conditions need early treatment by a dermatologist to protect the follicles
- Hair loss comes with unexplained weight loss, fever, night sweats or feeling generally unwell
- Hair thinning comes with new facial hair, a deepening voice or periods stopping
- You feel very low or anxious about your hair
If you feel unwell and are not sure where to turn, NHS 111 can advise. Call 999 in an emergency.
This list is not exhaustive. If you are not sure about something, see a doctor.
How we approach this at Aarva
Your appointment is with a doctor. We ask when the change started, what was happening in the months before, your periods, pregnancies, diet, medicines and family history. We look closely at the scalp and hair, and arrange blood tests where they will genuinely help.
If a medical cause is found, treating it comes first. If regenerative treatment might help, we explain the evidence honestly. You leave with a written treatment plan with clear pricing. There is no pressure to book on the day, and if we do not think a treatment will help, we will tell you. Our what to expect page explains the process, and you can meet our doctors or read about our women’s health care. For hair and other options, see our regenerative medicine page.
Questions patients ask
Will my hair grow back after shedding?
If the shedding is telogen effluvium, hair usually regrows once the trigger has passed, although it can take six to twelve months to look fuller again. Other causes vary, which is why finding the cause matters.
Can low iron cause hair loss even if I am not anaemic?
Low iron stores can be associated with hair shedding even when haemoglobin is normal. A ferritin test shows your iron stores. Iron supplements should only be taken after testing, as too much iron can also cause problems.
Is PRP a good option for thinning hair?
For some women with pattern hair loss, PRP may give a modest improvement in density, and there is supporting trial evidence. It is not suitable for every cause of hair loss, results vary, and medical causes should be ruled out first.
Should I see a trichologist or a doctor?
If there is any chance of a medical cause, such as low iron, a thyroid problem, a hormonal condition or scalp inflammation, a doctor can examine you, arrange tests and prescribe treatment where needed. That is usually the right starting point.
If your hair has changed and you want to know why, the first step is a conversation with a doctor. You can book a consultation, or use find your starting point to see where to begin.
This article is general information and does not replace a consultation with a doctor.
