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Hair fall and thinning: causes in men and women

Losing 50–100 hairs a day is normal. Hair fall becomes worth investigating when you notice thinning, a widening parting, a receding hairline or sudden heavy shedding.

Common causes

  • 01Pattern hair loss (androgenetic alopecia), which is genetic and hormonal
  • 02Heavy shedding 2–3 months after illness, surgery, childbirth, crash dieting or major stress (telogen effluvium)
  • 03Thyroid disorders
  • 04Iron deficiency
  • 05Patches of hair loss (alopecia areata)

In women, iron deficiency, thyroid problems and PCOS are worth checking together.

In men, hair loss is usually genetic pattern loss. Treatments work best at keeping the hair you still have, so starting early helps.

What a doctor may check

Ferritin and thyroid (TSH). A dermatologist can examine your scalp.

When to see a doctor

See a dermatologist for patchy loss, a painful or scarred scalp, or sudden heavy shedding.

This page is general information, not a diagnosis. Venva's content is written against clinical guidelines and systematic reviews, listed below. See our medical disclaimer.

References

  1. 1.Iron-deficiency anemia. New England Journal of Medicine, 2015.doi:10.1056/NEJMra1401038
  2. 2.Hypothyroidism. The Lancet, 2017.doi:10.1016/S0140-6736(17)30703-1
  3. 3.Recommendations from the 2023 International Evidence-based Guideline for PCOS. Journal of Clinical Endocrinology & Metabolism, 2023.doi:10.1210/clinem/dgad463

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