KeraThinning hair in women: what causes it, and what the evidence says helps
A widening part or a smaller ponytail usually has an identifiable cause. Here is how female pattern hair loss differs from shedding, what the evidence says about treatment, and when to see a doctor.
The short answer
Thinning hair in women is most often caused by female pattern hair loss, an inherited, gradual shrinking of the follicles that usually shows as a widening part and a smaller ponytail, or by temporary shedding after illness, childbirth, weight loss or stress. Low iron, thyroid problems, hormonal conditions and medication can also cause or add to it, so a doctor's assessment and blood tests are the sensible first step. Pattern hair loss will not reverse by itself, but treatment can slow it and help some women regrow hair. Topical minoxidil has the strongest evidence, and it works better when started early.
Thinning is hard to notice until it is well under way. There is rarely one dramatic day. There is a part that seems wider in a certain light, a hair tie that now goes round one more time, and a comment from a hairdresser you try to forget.
It is also far more common than the silence around it suggests. DermNet, a dermatology reference, says around 40% of women show signs of hair loss by the age of 50. A study of adult women in Brazil found a similar age pattern, with female pattern hair loss rising from 8% of women in their twenties to 68% of those aged 60 to 75. Figures differ between populations and methods, but the direction is consistent.
Is your hair thinning, or shedding?
They are different problems that can look alike and sometimes overlap.
| Shedding (telogen effluvium) | Pattern hair loss | |
|---|---|---|
| How it starts | Fairly suddenly, usually after a trigger | Gradually, over years |
| What you notice | Far more hair in the drain and brush | A wider part and less hair overall, not necessarily more in the drain |
| Hairs on your head | Normal thickness, fewer of them | Increasingly fine and short |
| Where | All over | Mostly the top of the head, with the front hairline usually kept |
| Outlook | Usually recovers within six to nine months once the trigger has passed | Tends to progress without treatment |
If you recently had an illness, a baby, major stress or rapid weight loss, read the guides on telogen effluvium and postpartum shedding. If you are finding hair and are not sure what it means, start with why your hair is falling out, and do the bulb check to rule out breakage.
What female pattern hair loss looks like
Female pattern hair loss is inherited. Over successive growth cycles, affected follicles shrink, the growth phase shortens, and each new hair comes in finer and shorter than the one before it. Eventually some follicles stop producing visible hair.
The usual signs are:
- A part that is getting wider, particularly from the front towards the crown
- A thinner ponytail
- Scalp more visible at the top of your head under bright light
- Hair near the temples that sometimes recedes
It rarely causes complete baldness in women, though some develop widespread thinning. Its hallmark is the change in the hairs themselves, which is why it is often missed: it can happen without any noticeable increase in shedding.
Other causes of hair loss in women
Before anyone can say this is pattern hair loss, other causes should be considered. Some are easy to treat, and you can have more than one at once.
- Low iron. Women with non-scarring hair loss have lower ferritin on average, although how far low iron drives the loss is still debated.
- Thyroid disease. An underactive or overactive thyroid can cause thinning all over the scalp, often months after the thyroid problem starts.
- Hormonal conditions. Polycystic ovary syndrome is common. Acne, irregular periods and excess facial or body hair suggest a raised androgen level and should be mentioned to your doctor.
- Medication. Check the leaflet for anything started in the months before the change, but do not stop a medicine without speaking to the prescriber.
- Traction. Long-term tight styles cause thinning at the hairline and temples, and it can become permanent.
- Scarring alopecia. Burning, itching or tenderness, or a hairline receding in a band, needs prompt assessment, because the follicles are destroyed for good.
What a doctor may do
Your doctor will usually ask about your history and look at your scalp and the pattern of the hair loss. Blood tests commonly include iron stores and thyroid function, along with hormones if your symptoms suggest it. Most women with pattern hair loss have normal androgen levels. A small scalp biopsy may sometimes be needed to confirm the diagnosis.
Take a list of everything you take, including supplements. High-dose biotin can distort some blood test results, which matters at exactly this point.
The treatment options, and how good the evidence is
This table is a guide to the conversation, not a recommendation. Which option suits you, if any, depends on your diagnosis, health and plans for pregnancy.
| Option | What it is | What the evidence says |
|---|---|---|
| Topical minoxidil | Non-prescription scalp treatment, FDA-approved for women | The best evidence available; better than placebo in randomised trials |
| Low-dose oral minoxidil | Prescription tablet, used off-label | Growing but mostly lower-quality evidence; needs medical supervision |
| Spironolactone and other anti-androgens | Prescription tablets, used off-label | Commonly prescribed, but better trials are still needed |
| Finasteride | Prescription tablet, used off-label | Three trials in the Cochrane review found it no better than placebo; not for women who could become pregnant |
| Low-level laser devices | At-home combs and caps | Mixed, low-quality evidence |
| Platelet-rich plasma | Injections of your own blood product | Still being studied |
| Hair transplant | Moves existing follicles to thinner areas | Suitable for some women, depending on how much healthy hair remains |
Minoxidil for women: what to know before you ask
Minoxidil is the option most women will come across first, so it is worth being clear about what the research does and does not show.
Some other things your doctor may discuss:
- It can get worse first. The American Academy of Dermatology says hair loss may temporarily increase in the first two to eight weeks.
- It is slow. The AAD says it takes about six to twelve months of continuous use to know whether it is working.
- It only works while you use it. If you stop, the benefit fades, and shedding gradually returns.
- It has side effects. Scalp irritation and unwanted hair growth elsewhere are the main ones, and the stronger strength is more likely to cause them.
- Pregnancy matters. The AAD advises against minoxidil if you are pregnant, planning a pregnancy or breastfeeding. Prescription hair-loss tablets may cause birth defects, so they are not an option if you are pregnant or planning a pregnancy, and the AAD says premenopausal women taking them should use birth control.
Low-dose oral minoxidil is increasingly talked about online. It is a prescription decision, not something to arrange for yourself. A recent systematic review reported hair density improvements alongside side effects including unwanted hair growth, fluid retention, dizziness on standing and headache, and oral minoxidil carries a boxed warning about serious heart-related events, which is why doctors screen patients first.
How to regrow thinning hair: an honest expectation
If you take away one thing, make it this: in pattern hair loss, treatment is mostly about keeping what you have, with some regrowth as a bonus for some people. Treatment works better the earlier it starts, while follicles are still producing hair.
Supplements and home remedies do not change that picture. The AAD describes the evidence on supplements as mixed. Correcting a measured deficiency is worthwhile, but extra vitamins on top of a good diet have no demonstrated benefit. Rosemary oil has one trial, in men with androgenetic hair loss, with no placebo group, and scalp massage has less. They are low-risk, but neither should delay a medical appointment.
What you can do in the meantime
Make your hair look fuller. Lightweight products at the roots, the right cut and the methods in our volume guide change how your hair looks, whatever the cause. So do the ideas in our thicker hair guide.
Consider camouflage. Coloured sprays and bulking fibres hide the scalp along the part, and wigs and hair toppers are options if you want them. There is nothing to be embarrassed about in using them, and they do not stop you from treating the cause.
Protect what is there. Gentle detangling, less high heat and loose styles all help to prevent breakage from adding to the loss.
Keep a photo record. Take a monthly photo of your part in the same light. Hair loss and treatment both move too slowly to judge in the mirror, and the photos are useful to your doctor.
Look after how you feel. Hair loss can affect wellbeing and confidence, and that is a good enough reason to book an appointment on its own. The NHS suggests telling your GP if it is affecting you, and they can arrange support.
Common questions
Can thinning hair grow back in women?
Sometimes, depending on the cause. Hair lost to temporary shedding usually returns once the trigger has passed. With female pattern hair loss, treatment can slow further loss and some women regrow some hair, but results vary, and the benefit lasts only as long as treatment continues. Scarring conditions cause permanent loss, so early diagnosis matters.
Does minoxidil work for women?
The evidence says it does for many women with pattern hair loss. A 2016 Cochrane review found that women using it were about twice as likely as those on placebo to have at least moderate regrowth, though results vary and many trials had weaknesses. It should be discussed with a doctor, and should be avoided in pregnancy, when planning a pregnancy and when breastfeeding.
At what age does female pattern hair loss start?
It usually begins in midlife, in the 40s to 60s, but can start earlier. It becomes more common with age, particularly after the menopause, so a change in your 20s or 30s is not impossible, and is still worth having checked.
What deficiency causes hair thinning in women?
Low iron is the one most often checked, and low protein, zinc and biotin are also recognised causes of hair loss. They are not always the explanation, and only a blood test can show a deficiency. Do not start high-dose supplements on a guess: too much of some nutrients can itself cause hair loss.
Is hair thinning in women hormonal?
It can be. Polycystic ovary syndrome is a common cause, and childbirth, stopping the pill and the menopause can all play a part. But most women with pattern hair loss have normal androgen levels, so normal blood results do not rule it out. Acne, irregular periods or extra facial hair are worth mentioning to your doctor.
Should I see a GP or a dermatologist for thinning hair?
Start with your GP or family doctor, who can review your history and arrange blood tests, then refer you if needed. Go sooner, and ask about a dermatologist, if there are bald patches, a receding band at the front, or an itchy, burning or painful scalp.
Kera offers hair-care lifestyle suggestions, not medical advice. It does not diagnose or treat any condition.