What causes hair loss in women?
Last updated September 3, 2026.
First the baseline: losing 50 to 100 hairs a day is normal. Real loss falls into patterns - female-pattern thinning (gradual, crown and parting, genetic and hormonal), telogen effluvium (sudden shedding 2 to 3 months after a baby, illness, surgery, or severe stress - usually regrows in 6 to 12 months), medical causes (iron deficiency, thyroid, low vitamin D), and mechanical damage from tight styles and heat. See a doctor for sudden loss, patchy loss (suggests alopecia areata), scalp itching or scaling, loss after a new medication, or shedding clearly beyond brush level - a few blood tests answer most medical causes. Pymander is a free AI doctor, 24/7 by text, and can help you sort the pattern.
What to do
- Calibrate against 50 to 100 a day: the brush is usually normal cycling, not loss.
- Look back 2 to 3 months for the trigger: birth, illness, fever, surgery, diet, stress.
- Ask for the three labs: iron (ferritin), thyroid (TSH), vitamin D.
- Loosen the styling: tight ponytails, braids, and extensions pull hair out over time.
Related questions
- How do you treat dandruff?
- How do you tell if you have a thyroid problem?
- How do you tell if you are anemic?
- What helps with menopause hot flashes?