Hormonal hair loss in women: androgens, thyroid, pregnancy and the pill on one map

"Hormonal hair loss" is a phrase many women hear, often without a clear explanation of which hormone is involved or what can be done. Hormones do play an important part in the hair cycle, but several different hormonal situations can affect hair in different ways. Androgens, thyroid hormones, the changes of pregnancy and birth, hormonal contraception and menopause all have their own patterns and timelines.

This guide puts these together on one map, so you can see how each one tends to affect hair, which clues point towards it, and what a doctor might check. This is general information, not personal medical advice. Please do not start or stop hormonal medicines without speaking to a doctor.

The short answer

• Hormones influence how long hairs grow and rest, so changes in hormone levels can alter hair density or trigger shedding ¹.
• Androgens can contribute to female pattern hair loss, especially in conditions such as polycystic ovary syndrome, although many women with pattern thinning have normal hormone levels ²³.
• Both underactive and overactive thyroid can cause hair thinning, usually alongside other symptoms ⁴⁵.
• Shedding a few months after giving birth is common and usually settles ⁶.
• Starting or stopping hormonal contraception can affect hair in some women ⁷.
• Menopause is often associated with thinner hair, and may make pattern thinning more noticeable ⁸.

How hormones affect the hair cycle

Each hair follicle cycles through a long growth phase, a short transition phase and a resting phase before the hair falls out and a new one starts. Hormones can change this cycle in two broad ways:

• They can shorten the growth phase and shrink follicles over time, producing finer, shorter hairs. This is the process behind pattern hair loss ¹.
• They can push many hairs into the resting phase at once, leading to diffuse shedding a few months later. This is called telogen effluvium ⁹.

Knowing which of these is happening helps decide what to do. Pattern thinning usually develops slowly over months or years, while telogen effluvium often starts more suddenly after a trigger.

The hormonal map

Androgens and polycystic ovary syndrome

Androgens are often called male hormones, but women produce them too, in smaller amounts. In women with a genetic tendency, androgens can contribute to follicle shrinkage on the top of the scalp. This is one part of the picture in female pattern hair loss ¹.

Polycystic ovary syndrome is a common condition that can raise androgen levels. Signs include irregular or missed periods, acne, increased hair on the face or body, and thinning hair on the scalp. Not everyone with PCOS has all of these ². If your thinning comes with these signs, it is worth asking a doctor about PCOS. See PCOS and hair loss.

It is important to know that many women with female pattern hair loss have normal androgen levels on blood tests. This suggests that follicle sensitivity, rather than hormone levels alone, often plays a large part ³.

Anti-androgen treatment

Some doctors use anti-androgen medicines such as spironolactone for selected women with pattern thinning, especially when there are signs of androgen excess. Evidence is growing but still limited, these medicines are used off-label for hair, and they are not suitable during pregnancy ¹⁰¹¹. See spironolactone for hair loss.

Thyroid hormones

Thyroid hormones help control the body's metabolism, including the activity of hair follicles. Both too little and too much thyroid hormone can lead to diffuse thinning.

• Underactive thyroid (hypothyroidism) can cause tiredness, weight gain, feeling cold, constipation, dry skin and dry or brittle hair ⁴.
• Overactive thyroid (hyperthyroidism) can cause weight loss, anxiety, a fast or irregular heartbeat, sweating and fine, thin hair ⁵.

Thyroid conditions are more common in women and can be checked with a simple blood test. Once thyroid levels are treated and stable, hair often improves gradually, although this can take months. See thyroid and hair loss.

Pregnancy and birth

During pregnancy, many women notice their hair feels thicker. This is partly because fewer hairs enter the resting phase. After birth, hormone levels change quickly and many of those hairs shift into the resting phase together. A few months later, they shed ⁶.

Postpartum shedding usually starts two to four months after birth and often settles within a year. It can feel dramatic, especially around the temples, but it is very common ¹². If shedding continues well beyond a year, or there are signs of thinning on top, a doctor may check iron and thyroid levels and look for pattern hair loss that the shedding has made more visible. See postpartum hair loss and how long postpartum hair loss lasts.

Pregnancy loss can trigger a similar shedding pattern. See hair shedding after pregnancy loss.

Hormonal contraception

Hormonal contraception contains synthetic versions of oestrogen, progestogen or both. Its effects on hair vary:

• Some women notice shedding after starting or stopping the pill, which is thought to reflect a change in hormone levels similar to a mild telogen effluvium.
• Some progestogens have more androgen-like activity than others, and in women prone to pattern hair loss, these may be less suitable.
• Some combined pills contain progestogens with anti-androgen effects and are sometimes considered for women with PCOS-related symptoms.

Hair loss is listed among the possible side effects of some contraceptive pills ⁷. If you think your contraception is affecting your hair, discuss it with your doctor rather than stopping suddenly, as other methods may suit you better. See birth control and hair loss.

Perimenopause and menopause

As oestrogen falls around menopause, the balance between oestrogen and androgens shifts. Many women notice their hair becoming thinner, finer or drier during this time ⁸. Female pattern hair loss is common after menopause, although it is not fully clear how much is due to menopause itself and how much to ageing and genetics ¹³.

Other menopausal symptoms include period changes, hot flushes, night sweats, sleep problems and mood changes ¹⁴. Hormone replacement therapy is mainly used for these symptoms, and its effect on hair is not well established. See menopause and hair loss and thinning hair in your 40s.

Other hormones worth knowing about

A few less common situations can also affect hair:

• High prolactin, which can cause irregular periods and breast discharge.
• Cortisol excess, such as in Cushing's syndrome or long-term steroid use.
• Some medicines that act on hormones, including certain cancer treatments.

These usually come with other symptoms, and a doctor will consider them if the history suggests it.

What a doctor might check

A doctor will usually start with questions about your periods, pregnancies, contraception, skin, weight changes, other symptoms, family history and the timeline of your hair changes. They will examine the scalp and sometimes the skin for signs of androgen excess.

Depending on what they find, blood tests may include thyroid function, a full blood count and ferritin, and sometimes androgen levels or other hormone tests ¹⁵. Hormone tests are most useful when there are other clues, rather than as a routine for every woman with thinning. See ferritin and women's hair loss.

Treatment depends on the cause

• If a hormonal condition is found, such as thyroid disease or PCOS, treating it is the first step.
• If the problem is telogen effluvium after birth or a pill change, it often settles on its own, and gentle care is usually enough.
• If it is female pattern hair loss, topical minoxidil is the most established treatment, with other medicines considered in selected women ¹⁶. See female pattern hair loss treatment and minoxidil for women.

Whatever the cause, hair responds slowly, and most treatments need several months before they can be judged.

Caring for hair while the cause is worked out

Finding the hormonal cause can take a few appointments and blood tests. In the meantime, some simple habits can help hair look and feel its best:

• Wash and condition regularly with gentle products. Washing does not cause hair loss; hairs that come out during washing were already loose.
• Detangle gently, starting from the ends, with a wide-tooth comb.
• Avoid tight styles that pull at the hairline, such as tight ponytails or buns.
• Reduce heat styling and harsh chemical treatments while hair feels fragile.
• Eat regular balanced meals with enough protein and iron-rich foods.
• Keep a simple record of your periods, contraception changes, symptoms and photos of your part every few months. This helps a doctor see patterns over time.

It is also worth remembering that more than one hormonal factor can be present at once. For example, postpartum shedding may reveal underlying pattern thinning, or a thyroid problem may develop during perimenopause. A step-by-step approach with a doctor usually works better than trying many remedies at the same time.

Common mistakes

• Calling all thinning "hormonal" without identifying which hormone or condition is involved.
• Requesting a long list of hormone tests when the history does not suggest a hormonal condition.
• Stopping contraception suddenly without a plan for alternative contraception.
• Assuming normal hormone tests rule out pattern hair loss.
• Using hormonal supplements or creams without medical advice.
• Ignoring symptoms such as irregular periods, weight changes or a fast heartbeat that may point to a treatable condition.

Questions to ask a doctor

• Which type of hair loss do I seem to have: pattern thinning, shedding or both?
• Do my symptoms suggest a hormonal condition such as PCOS or a thyroid problem?
• Which blood tests are worth doing, and which are unlikely to help?
• Could my contraception be affecting my hair, and are there alternatives?
• If I have pattern hair loss, what treatments are suitable for me?
• How long should I wait before judging whether treatment is working?

The bottom line

Hormones are involved in many types of women's hair loss, but "hormonal" can mean several different things. Androgens and PCOS tend to cause thinning on top, thyroid problems cause diffuse thinning with other symptoms, birth and pill changes often trigger temporary shedding, and menopause can make pattern thinning more visible. Identifying which situation applies, with help from a doctor and targeted tests, is the best way to choose a sensible treatment. For a wider overview, see hair loss in women.

Frequently asked questions

What is hormonal hair loss in women?

It is a general term for hair loss linked to hormones, including androgens, thyroid hormones, pregnancy, contraception and menopause. Each tends to cause a different pattern.

Can PCOS cause hair loss?

Yes. Polycystic ovary syndrome can raise androgen levels, which may contribute to thinning on top of the scalp, often alongside irregular periods, acne or extra facial hair.

Can thyroid problems cause hair loss?

Both underactive and overactive thyroid can cause diffuse thinning, usually with other symptoms. A blood test can check thyroid function.

Can the pill cause hair loss?

Some women notice shedding after starting or stopping hormonal contraception, and some progestogens may be less suitable for women prone to pattern hair loss. Discuss concerns with a doctor.

Should I have my hormones tested?

Hormone tests are most useful when there are other clues, such as irregular periods or signs of androgen excess. Many women with pattern thinning have normal hormone levels.

Does postpartum hair loss mean a hormone problem?

Usually not. Shedding after birth is common and reflects normal hormone changes. If it lasts well beyond a year, a doctor can check for other causes.

Is hormonal hair loss treatable?

Treatment depends on the cause. Treating thyroid disease or PCOS can help, temporary shedding often settles, and pattern thinning has established treatments such as topical minoxidil.

Does menopause cause hair loss?

Many women notice thinner hair around menopause, and pattern thinning is common afterwards, although ageing and genetics also play a part.

Educational content. Not medical advice.