Endocrine Alopecia: How Hormones Affect Hair and What to Check
Endocrine alopecia is a broad term for hair loss linked to the endocrine system, the glands that make hormones, such as the thyroid, ovaries and adrenal glands. If your hair has thinned alongside changes to your periods, weight, energy or mood, a hormonal cause is worth looking into. This guide explains which hormone conditions affect hair, how the patterns differ, what a GP is likely to check, and how to look after your hair while you get answers.
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Endocrine alopecia means hair loss driven by a hormone problem rather than by genes alone. The most common causes are thyroid conditions, PMOS (previously called PCOS), the menopause and the hormone drop after childbirth. The NHS lists hair loss among the symptoms of both an underactive and an overactive thyroid. Because the cause sits inside the body, a GP assessment and blood tests come first.
Key takeaways
- The NHS lists dry hair or hair loss as a symptom of an underactive thyroid, and patchy hair loss or thinning as a symptom of an overactive thyroid.
- The NHS describes PMOS, previously called PCOS, as a hormone condition that can affect hair growth, with hair loss among its main symptoms.
- Hormone shifts such as childbirth can trigger shedding 2 to 4 months later, according to DermNet.
- Hair often settles once the underlying hormone problem is managed, but it takes months because hair grows about one centimetre a month.
- Gentle hair care helps hair look fuller in the meantime but cannot fix a hormone problem.
What is endocrine alopecia?
Hormone-driven hair loss is hair loss caused or worsened by an imbalance in the body's hormones, rather than by damage to the hair or by inherited pattern thinning alone. It is an umbrella term rather than one condition, covering hair changes linked to the thyroid, the ovaries, pregnancy, the menopause and other glands.
Hormones set the pace of the hair cycle. DermNet explains that each scalp hair grows for around three years and then rests for about three months before it is shed. When hormone levels shift sharply, many hairs can move into the resting phase together, and the result is noticeable shedding a few months later. With some conditions, such as PMOS, hormones can also make follicles produce finer hairs over time. Because of that, the pattern of hair change is often a useful clue to the cause.
Which hormone problems cause endocrine alopecia?
The hormone problems most often behind hormonal hair loss are thyroid conditions, PMOS, the menopause and perimenopause, and the hormone drop after childbirth. Each has its own pattern and its own set of other symptoms, which is why a GP will ask about periods, weight, energy, temperature and mood as well as your hair.
| Hormone cause | Typical hair change | Other clues the NHS or DermNet describe |
|---|---|---|
| Underactive thyroid | Dry hair or hair loss, often diffuse | Tiredness, feeling cold, weight gain, low mood |
| Overactive thyroid | Patchy hair loss or thinning | Weight loss, fast heartbeat, sweating, trembling |
| PMOS (previously PCOS) | Thinning on the scalp, sometimes extra hair on the face or body | Irregular periods, oily skin or acne, weight gain |
| Menopause and perimenopause | Gradual thinning, wider parting | Hot flushes, poor sleep, period changes |
| After childbirth | Heavy shedding a few months after birth | Usually settles over a few months |
Our dedicated guides cover the two most common in depth: thyroid-related hair loss and PCOS hair loss. For hair changes around the menopause, see our guide to oestrogen and hair loss.
How does hormonal hair loss differ from genetic hair loss?
Hormonal hair loss differs from genetic pattern hair loss mainly in its timing and its company: hormone-related hair loss usually arrives alongside other symptoms and often starts or speeds up over months, while inherited pattern hair loss develops slowly over years in a typical pattern, often with a family history and no other symptoms.
The two can overlap. DermNet notes that postpartum shedding can resolve after a few months or transition into female pattern hair loss, and that female pattern hair loss is more common after the menopause. So a hormone change can unmask a pattern that was already developing. That is one reason to get hair loss looked at properly rather than assuming one explanation.
| Feature | Hormone-related hair loss | Inherited pattern hair loss |
|---|---|---|
| Speed | Often months | Usually years |
| Pattern | Diffuse shedding, or patchy with an overactive thyroid | Wider parting in women; hairline and crown in men |
| Other symptoms | Common: periods, weight, energy, temperature | Usually none |
| Family history | Not necessarily | Often |
Is it hair loss, hair shedding or hair breakage?
Hair loss, hair shedding and hair breakage are different problems, and separating them helps you and your GP find the cause. The NHS says losing 50 to 100 hairs a day is normal, so the question is whether you are losing more than your usual amount, and in what form.
Hair shedding means whole hairs, each with a small white bulb, falling out in greater numbers; DermNet says this typically appears 2 to 4 months after a trigger such as childbirth, illness, crash dieting or severe stress. Hair loss in the stricter sense means follicles producing less hair over time, or losing hair in patches. Hair breakage means strands snapping part-way along, often from dryness, and an underactive thyroid can leave hair drier and more prone to it.
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How is endocrine alopecia checked?
Hormonal hair loss is checked by a GP, who will ask when the hair change started, look at the pattern on your scalp, ask about other symptoms and your medicines, and usually arrange blood tests. Thyroid function and iron levels are among the most common checks, and a GP may look for signs of PMOS or the menopause depending on your age and symptoms.
It helps to arrive with notes: when shedding began, any illness, birth, weight change or stress in the three or four months before, changes to your periods, and whether anyone in your family has thinning hair. Take photos of your parting and crown if you can. The NHS advises seeing a GP if you are worried about your hair loss, and it is especially worth going if hair loss comes with tiredness, feeling hot or cold, weight change or irregular periods. If your question is about products or a routine rather than a medical one, you can talk to Gail Waterman, our co-founder, as an AI avatar on the Watermans homepage.
Get urgent help if
hair loss comes with a racing heartbeat, weight loss despite eating more, or severe tiredness and feeling unwell. See a GP promptly, or call NHS 111 if you are not sure where to go.
Does hair come back once the hormones are managed?
Hair often improves once the underlying hormone problem is managed, particularly when the main change was shedding, but it takes months rather than weeks. New hair grows about one centimetre a month, according to DermNet, so visible fullness usually lags well behind any improvement in blood results or other symptoms.
The outlook depends on the cause. Shedding after childbirth or a short illness usually settles on its own. Hair changes from thyroid conditions may improve once thyroid levels are stable, though this can take several months. Hair thinning linked to PMOS or the menopause tends to be more gradual and ongoing, and deserves a longer-term plan with your GP. In all cases, give any routine at least three months before judging it, and keep photos to track progress. Our guide to what causes telogen effluvium explains the shedding timeline in more detail.
Can diet support hair during hormonal hair loss?
Diet can support hair during hormonal hair loss by avoiding shortfalls that make thinning worse, especially low iron and too little protein or overall energy. It cannot correct a hormone imbalance, but under-eating or iron deficiency on top of a thyroid problem or PMOS makes hair noticeably thinner.
The NHS says women aged 19 to 49 need 14.8mg of iron a day and those 50 and over need 8.7mg, with good sources including red meat, beans, nuts, dried fruit and fortified cereals. Avoid crash diets, which DermNet lists as a shedding trigger. Do not take iodine or thyroid supplements without medical advice, and do not start high-dose iron unless a blood test shows you need it. Our guide on ferritin levels and hair explains the iron test.
How should you care for your hair in the meantime?
Caring for your hair while a hormone cause is sorted out means being gentle: a mild shampoo on the scalp, conditioner on the lengths, low heat, loose styles and a cut that suits finer hair. These steps do not change hormones, but they reduce breakage and help thinner hair look fuller.
Wash as often as your scalp needs, blot rather than rub with a towel, and use a wide-tooth comb on wet hair. For special occasions, hair building fibres can disguise a see-through parting or crown and wash out with shampoo. For how DHEA and cortisol connect to shedding and extra hair, see our guide to adrenal hormones and hair.
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What are the frequently asked questions about endocrine alopecia?
What is endocrine alopecia?
It is hair loss linked to a hormone problem, such as a thyroid condition, PMOS, the menopause or the hormone drop after childbirth.
Can thyroid problems cause hair loss?
Yes. The NHS lists dry hair or hair loss as a symptom of an underactive thyroid, and patchy hair loss or thinning as a symptom of an overactive thyroid.
Is PCOS hair loss a type of hormonal hair loss?
Yes. PMOS, previously called PCOS, is a hormone condition, and the NHS lists hair loss among its main symptoms.
Will my hair grow back when my hormones settle?
Hair often improves, especially when the main change was shedding, but it takes months because hair grows about one centimetre a month.
Which blood tests check for hormonal hair loss?
A GP will choose the tests, but thyroid function and iron levels are common checks when hair is thinning.
Can a shampoo fix hormonal hair loss?
No. A gentle shampoo helps the scalp stay comfortable and hair look fuller, but a hormone problem needs medical assessment.
When should I see a GP?
If you are worried about your hair, or if hair loss comes with tiredness, weight change, feeling hot or cold, or irregular periods.
What is the bottom line on endocrine alopecia?
The bottom line on endocrine alopecia is that hair loss with other symptoms, such as tiredness, weight change or irregular periods, deserves a GP visit and blood tests before anything else. Once the cause is found and managed, hair often improves over months. Until then, keep your hair care gentle and your expectations realistic.
For gentle everyday washing while you get answers, a mild hair growth shampoo keeps the scalp clean and comfortable.
Sources & references
- NHS, Underactive thyroid symptoms, checked 18 September 2026.
- NHS, Overactive thyroid symptoms, checked 18 September 2026.
- NHS, Polyendocrine metabolic ovarian syndrome (PMOS), checked 18 September 2026.
- NHS, Symptoms of menopause and perimenopause, checked 18 September 2026.
- NHS, Hair loss, checked 18 September 2026.
- NHS, Iron, checked 18 September 2026.
- DermNet, Telogen effluvium, checked 18 September 2026.
- DermNet, Female pattern hair loss, checked 18 September 2026.
Watermans products are 100% cosmetic and do not treat medical hair loss. Individual results may vary.
