Hair loss in women

Two different problems

Women's hair loss is often described as one thing, but most of it falls into two groups that behave very differently.

Pattern hair loss (female pattern hair loss) is slow. Over months and years, the parting gets wider and hair over the top of the head thins. The front hairline usually stays where it was, which is one way it differs from the pattern in men. It is common: European guideline figures suggest that 3 to 6% of women under 30 are affected, rising to 29 to 42% of women aged 70 and over.⁵ It often starts in the late twenties and becomes most common after 50.⁶

Shedding (telogen effluvium) is sudden. Many hairs move into their resting phase at once and fall out together a few months later, so you notice hair everywhere: in the shower, on your pillow, in your brush. The hair thins all over rather than in one area. Read more in shedding after stress, illness or birth.

The two can overlap. A bout of shedding can make pattern thinning, which was slowly happening anyway, suddenly visible. If you are not sure which you have, a doctor can usually tell from your story and a look at your scalp.

Common causes and triggers

After giving birth

During pregnancy, many women notice thicker hair, because fewer hairs move into the resting phase. After birth, those hairs move on together. Shedding usually starts two to four months after the birth and usually lasts a couple of months, and full recovery is the usual outcome.¹ It can be alarming, but it is normal. If shedding goes on for more than six months, or the hair does not come back, see a doctor, because something else may be going on.^1,4

Iron

Iron deficiency is common in women who still have periods, because of monthly blood loss and pregnancy.³ Low iron is often found in women with hair loss, but studies disagree on how much it causes. What is clear is that iron-deficiency anaemia should be treated, and a ferritin blood test confirms whether your stores are low.³ Do not take iron tablets on a guess: too much iron is harmful.

Thyroid

An underactive or overactive thyroid can cause diffuse shedding.⁴ Other signs include tiredness, feeling cold or hot, weight change and changes in your periods. A blood test can check.

Hormones and PCOS

Some women with pattern hair loss have higher levels of androgens, the hormones that men usually have more of. Signs can include irregular periods, acne, and new hair on the face or body. Polycystic ovary syndrome (PCOS) is a common cause. A doctor may suggest hormone tests if you have these signs. For women with signs of raised androgens, the European guideline says a doctor can consider an anti-androgen treatment.⁵

Menopause

Pattern hair loss becomes more common after 50.⁶ Falling oestrogen levels around menopause may play a part, though the details are not fully understood. If your hair changed around menopause, the treatments below still apply. Talk to your doctor if you are thinking about hormone therapy, since it affects more than your hair.

Other things worth checking

Crash diets, low protein intake, major surgery, high fever, and some medicines can all trigger shedding.^1,4 So can tight hairstyles worn for long periods, such as tight ponytails, braids or extensions, which pull on the same follicles day after day. Changing the style early helps.

What helps pattern hair loss

Minoxidil

Topical minoxidil is the first choice. The 2017 European guideline gives it its strongest recommendation for women, either as a 2% lotion twice a day or a 5% foam once a day.⁵ In a Cochrane review, women using minoxidil were nearly twice as likely as those using a placebo to report moderate or marked regrowth.² The same review found no difference between 2% and 5% in hair counts, although that evidence was of low quality.²

Expect a possible shed in the first weeks, and judge the result at six months.⁵ Unwanted hair on the face can happen, especially if the product runs onto the forehead or cheeks. A foam, careful application and clean hands help. Read our minoxidil guide and how to use it, step by step.

Minoxidil tablets at a low dose are also used, on prescription. They are off-label, and the evidence is newer. See minoxidil: tablet or lotion?.

Spironolactone and other anti-androgens

Spironolactone is a tablet that blocks some effects of androgens. Dermatologists often prescribe it for women with pattern hair loss, usually alongside minoxidil, but it is off-label and the trial evidence is thin. In a small 24-week pilot trial of 48 women who all used minoxidil, more women taking spironolactone rated their hair as moderately or markedly better (38% against 9%). The difference in hair counts was not statistically clear, and over a third of the women taking it had irregular periods.⁷ The European guideline makes no recommendation for anti-androgens in women whose hormone levels are normal.⁵

Spironolactone must not be taken during pregnancy, so it is usually prescribed with reliable contraception. It is a decision for you and your doctor.

Finasteride

Finasteride is the other main hair-loss medicine, but it is mainly for men. In women, trials of finasteride 1 mg have not shown a clear benefit, and the European guideline suggests not using it in women after menopause.^2,5 It must not be used by anyone who is or may become pregnant, because it can affect a male baby's development. Some doctors prescribe it to women after menopause at other doses; this is outside the guideline.

Red light and microneedling

Red light devices showed benefits in women in short trials. Women using a laser comb gained about 20 thick hairs per square centimetre in 26 weeks, against about 3 with a sham comb.⁸ A helmet gave 37% more hair growth than a placebo helmet over 16 weeks.⁹ A Cochrane review still rated the evidence as low quality.² The guideline suggests light therapy as an add-on, not on its own.⁵ Microneedling has been studied mostly in men. See red light therapy and microneedling.

Supplements

Many hair supplements are marketed to women. Most have little evidence in people who are not deficient, and biotin can upset blood tests.^10,11 Test, don't guess. See hair supplements: what has evidence.

When to see a doctor

See a doctor if your hair loss is sudden, patchy, or comes with a sore or red scalp, irregular periods, acne, new facial hair, or tiredness. Ask about a blood count, ferritin and thyroid tests.^3,4 Read when to see a doctor about hair loss for what to expect.

Hair loss can hit hard, and it is often brushed off as cosmetic. It is not trivial, and you deserve to be taken seriously. If the first answer you get does not help, it is reasonable to ask for a referral to a dermatologist.