Hair thinning
Also called: hair falling out, wider part, thinner ponytail, hair loss, receding hairline
The hair in the drain, the ponytail that got thinner, the part that widened. This one lands harder than people expect it to, and it is not vain to be upset by it. It is also one of the most reversible things on this list, because it very often has a specific cause sitting on an ordinary blood test that nobody has run.
What is actually happening
Estrogen keeps hair in its growing phase for longer. As it falls, more follicles move into the resting phase at once, which is why shedding can look sudden rather than gradual. At the same time, less estrogen means the androgens you have always had are relatively less opposed, and they thin the follicles along the part and the temples — the pattern women recognize in the mirror. Iron and thyroid sit underneath both mechanisms, which is why they are the first things to check rather than the last.
If you try one thing
Asking for a ferritin test
The most common reversible cause of shedding in midlife, and it does not show on a standard blood count.
The only starting point on this list that is a test rather than a treatment, and deliberately so. If low iron is what is doing this, nothing you buy will hold while it stays low. If it is not, you have ruled out the most common reversible cause for the price of one blood test.
Ask your provider for ferritin specifically — normal haemoglobin can sit alongside empty iron stores, so a standard blood count will look fine. Shedding is associated with ferritin under about 30 ng/mL, and many clinicians aim for 40–60 for regrowth. Do not start iron without testing: too much is its own problem, and it is not one you can feel coming.
Add it to your phone the next time you book anything medical.
On a hard day: Write the word "ferritin" in your notes now, so it is there when someone asks.
When you might notice
Three to six months after levels come up. Hair is slow, and nothing changes that.
Roughly what it costs
Free
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What to say to a doctor
Ferritin, thyroid (TSH plus free T4) and vitamin D are the ones worth asking about. Ferritin is the one most often missed, because a level a lab calls normal can still be too low for hair — hair is the first thing your body stops spending iron on. If the shedding is sudden and heavy rather than gradual, say so, because that pattern has its own set of causes.
Guía is not a doctor. This is what to bring so the appointment goes somewhere.
Something else bothering you
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