Hair Thinning in Women: What to Check First, in Order

In brief

Hair thinning in women usually comes from one of five causes: a shedding surge after stress, illness or childbirth; low iron; thyroid changes; menopause; or tension from tight styles. Find out which one it is before you buy anything, starting with a GP blood test for iron and thyroid.

By Vitalii Prisacari, VTCT Skills Level 3 Diploma in Women's Hairdressing, including the Level 4 Hair and Scalp unit, State Registered Graduate Hairdresser, founder of Matted Hair London. Helped 1,000+ people since 2020. Reviewed September 2026. This article shares hair-care experience, not medical advice; thinning with a medical cause belongs with your GP first.

Thinning or normal shedding: settle this first

Everyone loses 50 to 100 hairs a day, says the American Academy of Dermatology, and long hair makes that look alarming in a plughole. Thinning looks different: a widening parting, a ponytail that needs an extra twist of the band, visible scalp under bathroom lighting, or shedding that doubles for weeks.

One heavy day means little. Heavy shedding every day for a month is worth acting on. Photograph your parting and your ponytail today, under the same bathroom light, and take the same photos again in six weeks.

The five common causes, and how each behaves

Shedding surge (telogen effluvium). Two to four months after a trigger such as childbirth, high fever, illness, surgery, crash dieting or intense stress, hair starts coming out all over the head. In most cases it settles within months once the trigger has passed.

Low iron. Common in women with heavy periods or restricted diets. The hair thins gradually, and energy tends to dip with it.

Thyroid changes. Strands often turn drier and finer at once, so you notice the texture change as much as the lost volume.

Menopause. As oestrogen’s protective effect drops, strands miniaturise slowly, most visibly at the crown and temples.

Traction. Years of tight ponytails, buns, braids or heavy extensions thin the hairline first. Loosen the styles early and the hairline usually grows back.

What to ask your GP to check

Ask for ferritin, which measures iron stores, and a thyroid function test. Bring a timeline: when the thinning started, what happened in the months before, and whether the shedding is diffuse or patterned. The NHS guide to hair loss is worth reading before you go.

Book a GP appointment this week for sudden patchy loss, loss with scalp pain, redness or scarring, or shedding with other symptoms. Pattern-type thinning has licensed treatments that work best started early; ask your GP or pharmacist about them rather than buying promises online.

The postpartum special case

Postpartum hair loss tends to start around month three after birth, and the recovery is near-universal within a year. Pregnancy hormones hold hairs in the growing phase, so the hair feels thicker for months; after birth, that backlog releases together.

Handfuls in the shower are frightening, and after a birth they are normal. I restore postpartum matting regularly, without judgement. The weak spot is the nape of the neck, where matting tends to start: with a newborn, heavy shedding and no time to brush, loose hair collects and knots there first.

What actually helps, and what just sells

Treat whatever cause your GP finds, and handle the hair gently so breakage does not pile on top of the shedding. Use a soft flexible-pin brush, ends first. A silk pillowcase cuts friction at night. Before you buy a brush, read how to choose a detangling brush for fine hair.

Most “growth” shampoos touch your scalp for seconds before you rinse them off, and regrowth gummies taken without a deficiency mostly help the seller. Be wary of anything that promises visible regrowth in weeks.

Styling thinning hair without making it worse

For volume without strain, try a shallow zigzag parting, blow-dry the roots against their growth direction, and use a lighter conditioner that does not flatten. Leave out aggressive teasing, which snaps the fine regrowth you most need to keep, and save tight styles and heavy extensions for after the hair recovers.

The connection nobody mentions: thinning hair tangles and mats faster

Finer strands drift and wrap around each other more easily than thick ones.

A shedding surge is often where matting starts. In my own records, depression, illness and hospital stays came before the matting for 42% of all my clients, around 420 people. My records cover more than 1,000 clients since 2020, and my study of what causes severe matting breaks down the other causes.

If you are shedding heavily, brush at least three times a day, so the shed hairs leave your head instead of felting into the hairs still attached. The morning brush and the one before sleep matter most. The rest of my daily routine for preventing matting is built for periods like this.

A section that has fused solid needs dematting; matted hair removal in London, without cutting explains how I work.

Frequently asked questions

Why is my hair suddenly thinning?

Most often it is a shedding surge, and the cause sits a few months back. Count back two to four months. A fever, a birth, an operation, a crash diet or a hard stretch of stress usually sits there, and the shedding arrives late, like a delayed bill.

What vitamin deficiency causes hair thinning in women?

Low iron (ferritin) is the most common nutritional cause in women, with vitamin D worth checking alongside it. For scale, the UK’s National Diet and Nutrition Survey finds low iron stores in around 1 in 5 women of childbearing age. Test before supplementing: dosing a deficiency you do not have does nothing for hair and can be harmful.

Does menopause hair thinning stop?

Usually, yes: menopausal shedding slows once the hormonal shift stabilises, and the fast phase of loss settles with it. Texture often stays finer and drier than before, which frizzes and tangles more easily. So brush more gently, and give it more moisture than you used to.

Can thinning hair grow back?

Often, yes. Hair lost to a shedding surge or a deficiency usually regrows fully once the cause resolves, with recovery over three to six months. The first sign is usually short new hairs standing up along the parting. Brush them gently, ends first, because fine regrowth snaps easily.

Should I use a detangler on thinning hair?

On loose tangles, yes: a light detangler adds slip, so the brush pulls less on strands that are already shedding. On a mat it coats the outside and does not reach the knot. Leave a mat dry, and use product only once a section has started to open.

Gentle is the whole strategy

For knots from shed hair tonight, work with your fingers first, tips to roots, and put nothing on them yet. A section that stays solid under your fingers is a mat, and that is where home work stops. My guide sets out when home detangling is still safe and when to call a professional. We Save Hair, Not Cut It.

Related reading: When braids and protective styles cause thinning at the hairline · How to keep length while hair is regrowing · What dry shampoo does to shed hair

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