Guides · Guides · 7 min read
Thinning Hair in Women: Widening Part, PCOS, Thyroid and What Helps
By the Perfect 5 Clinic team · Updated September 2026
Hair thinning in women usually shows up as a wider parting, more scalp visible under the bathroom light, or a ponytail that feels smaller than it did a year ago. The most common reason is female pattern hair loss, which often runs in families. Thyroid problems, low iron stores and PCOS are the other usual suspects, and more than one can be going on at once. So the first step is working out the cause.
Why is my part widening?
A parting that gets wider while the front hairline stays roughly where it was is the classic sign of female pattern hair loss. The follicles along the top of the head slowly shrink, so each new hair grows back a little finer and shorter than the one before it. You don’t usually get bald patches. You see more scalp along the centre line and over the crown.
It is gradual, usually over years, and many women first notice it in their twenties or thirties, or around menopause. The part can widen without much extra hair coming out day to day, which is why it’s often first spotted in a photo.
Other common reasons hair looks thinner
- Thyroid problems, whether the thyroid is underactive or overactive. This tends to thin hair evenly across the whole scalp.
- Low iron stores. Anaemia is very common among women in India, and heavy periods or a diet low in iron make it more likely.
- PCOS, where higher levels of androgens (hormones usually thought of as male) can thin scalp hair while adding hair on the chin or upper lip.
- Starting, stopping or switching some medicines, including hormonal pills, which can set off shedding a few months later. Don’t stop a prescribed medicine on your own; ask the doctor who prescribed it.
- Tight hairstyles worn every day, like a tight bun, plait or ponytail, which pull at the hairline and temples. Loosening them early matters, because years of pulling can leave thin patches that don’t grow back.
- Breakage. Regular heat styling, bleaching, rebonding or smoothening can snap hair along its length, so it looks thin even when the roots are fine.
- A phase of extra shedding after an illness, a stressful time or childbirth, which usually settles on its own.
Which tests does a doctor usually ask for?
There is no single blood test for hair loss. Depending on your history and how your scalp looks, a doctor will often ask for a short set of tests to rule out causes that can be corrected. These commonly include:
- Complete blood count (CBC), to check for anaemia.
- Serum ferritin, which reflects your body’s iron stores. It can be low even when your haemoglobin is normal.
- Thyroid tests, usually TSH, sometimes with other thyroid hormone levels.
- Vitamin D and vitamin B12, particularly if your diet, time in the sun or symptoms suggest you could be short.
- Hormone tests, if you have irregular periods, acne, extra facial or body hair or other signs of PCOS. Your doctor decides which ones, and when in your cycle.
Your doctor may not need all of these, or may add others. Hold off on starting iron or vitamin supplements on your own before testing. They can muddy the results, and too much iron can cause harm.
A normal report also doesn’t mean the thinning is imagined. Pattern hair loss doesn’t show up in blood tests. It is diagnosed by examining the scalp closely, often with a magnifier that shows whether hairs along the part are getting finer. If you already have reports, bring them to a hair consultation at any of our clinics and we’ll go through them alongside a scalp check.
PCOS, thyroid and hair: what changes once the cause is treated
With PCOS, scalp thinning comes from how the follicles respond to androgens. Managing PCOS is a long-term job that may involve a gynaecologist or an endocrinologist along with changes to diet, activity and sleep. Hair responds slowly, over many months.
With thyroid-related thinning, hair usually improves once thyroid levels are under control, though it can take several months after your reports settle. Some women notice a little extra shedding early in treatment. Don’t stop or change your thyroid medicine because of it; speak to the doctor who prescribed it. If thinning carries on well beyond that, ask your doctor about a second cause such as pattern hair loss or low iron.
What actually helps
What helps depends on the cause, and it is often a combination. If tests show low iron, vitamin D or B12, correct it under a doctor’s guidance. If thyroid or PCOS is involved, keeping it well controlled with the right specialist matters more than anything you put on your scalp.
- For pattern hair loss, doctors can prescribe treatments that are applied to the scalp or taken by mouth. Which one suits you depends on your health and whether you are pregnant or planning to be.
- Looser hairstyles and gentler handling, so you aren’t losing length to pulling and breakage.
- In-clinic options such as PRP, added after a diagnosis to support the main plan.
Hair grows slowly, so most treatments need at least six months, often closer to a year, before you and your doctor can fairly judge them.
Can PRP help hormonal or PCOS-related thinning?
PRP (platelet-rich plasma, prepared from a small sample of your own blood and injected into the scalp) is sometimes used for female pattern hair loss, including in women with PCOS. GFC, a related preparation also made from your own blood, carries the same caveats. There are fewer and smaller studies of PRP in women than in men, and results vary. PRP doesn’t change hormone levels or fix a thyroid or iron problem, so its role is to support treatment of the cause. It takes several sessions, and the diagnosis comes first. Sessions can be uncomfortable and may leave the scalp tender, swollen or bruised for a day or two. PRP is usually avoided during pregnancy, with some blood or clotting disorders, while on blood thinners, or if there is a scalp infection.
Myths worth letting go of
“Only men get pattern hair loss.”
Women get it too. It just looks different: the front hairline usually stays put, while the part and crown slowly thin.
“My periods are regular, so it can’t be hormonal or pattern hair loss.”
Many women with pattern hair loss have regular periods and normal hormone and blood reports. Family history plays a big part, and a close scalp examination is what picks it up.
“Cutting my hair short will make it grow back thicker.”
A haircut doesn’t reach the follicle, so new hair grows the same. A shorter cut can still make thin hair look fuller.
When is it time for a hair assessment?
Book an assessment if your part or crown has looked noticeably wider for three months or more, if it keeps getting wider, or if thinning is affecting how you feel about yourself day to day. With pattern hair loss, earlier is better, because follicles that have been shrinking for many years are harder to bring back.
See a doctor sooner if you notice
- Round, smooth bald patches, or patches that appear within weeks.
- Redness, pain, burning, itching or scaling on the scalp, or a hairline moving back with irritated skin. Some scalp conditions can scar, and hair may not grow back in scarred areas.
- Thinning along with irregular or missed periods, new acne or extra facial hair.
- Thinning that comes on quickly along with a deepening voice, or facial or body hair that is growing fast. Please see a doctor promptly for this.
- Thinning along with tiredness, unexplained weight change, always feeling cold, or a racing heart.
- Thinning or patchy loss along with joint pain, mouth ulcers, a rash on the face or unexplained fevers.
- Loss of eyebrow or eyelash hair.
Take these to your hair assessment
- 1Photos of your parting and crown taken in the same light, a few weeks apart if you have them.
- 2Any blood reports from the last six months.
- 3A list of every medicine and supplement you take, including hormonal pills, and any you have recently started or stopped.
- 4Any recent illness, big weight change or stressful phase.
- 5Your usual period pattern, and whether your mother, sisters or aunts have thinning hair.
- 6Recent salon treatments such as rebonding, smoothening, bleaching or colour.
A useful assessment should end with a likely cause and a clear plan, and that plan may well be tests and time. If you’d like your scalp checked, you can book a hair consultation at our Lajpat Nagar or Indirapuram clinic, or at our clinics in Vaishali Nagar, Jaipur and Rajajinagar, Bangalore. We’ll examine your scalp, go through your reports with you and give you a straight answer on whether PRP or GFC makes sense for you, or whether something else should come first.
Written and edited by the Perfect 5 Clinic editorial team. Hair thinning often has more than one cause, so have your scalp and reports checked in person before starting any treatment.
Quick answers
Why is my hair thinning at the parting?
A widening part with the front hairline still in place is most often female pattern hair loss. Thyroid problems, low iron and PCOS can cause or add to it, so a scalp examination and a few blood tests are the usual starting point.
Which blood tests are done for hair thinning in women?
Doctors commonly ask for a complete blood count, serum ferritin (iron stores), thyroid tests such as TSH, vitamin D and vitamin B12, with hormone tests added if there are signs of PCOS. Your doctor decides the exact list.
Can PCOS cause hair thinning?
Yes. Higher androgen levels in PCOS can thin scalp hair along the part and crown, sometimes alongside acne or extra facial hair. Hair responds slowly once PCOS is managed, often over many months.
Will my hair grow back after thyroid treatment?
Usually, once thyroid levels are controlled, though it can take several months after your reports settle. If it doesn’t, ask your doctor to check for pattern hair loss or low iron.
Is PRP an option for PCOS-related thinning?
It is sometimes used for female pattern hair loss, including in women with PCOS, as support while the PCOS itself is managed. There are fewer studies in women than in men and results vary, so a proper diagnosis should come first.
When should I see a doctor about thinning hair?
If your part or crown has looked wider for three months or more or keeps getting wider, or you notice bald patches, scalp pain or redness, irregular periods or thyroid symptoms. An earlier assessment usually leaves more options open.
Book prp & gfc hair treatment at a clinic near you
This guide is general information, not medical advice; individual results and suitability vary. For advice about your own skin or hair, book a consultation at any Perfect 5 Clinic.