Hair falling out

Start three months ago

Before anything else, do this. Count back three months from when the shedding started, and write down what was happening then.

An illness with a fever. A surgery. A crash diet. A birth. A bereavement. A period of barely sleeping. A new medication. A month where you stopped eating properly.

Because here is the thing almost nobody is told, and it is the single most useful fact on this page.

Your hair does not shed when the stressor hits. Each follicle runs a cycle: a long growing phase lasting years, then a resting phase, then release. A physiological shock pushes a large batch of follicles out of growing and into resting all at once.

And then those hairs sit there. For about three months. Attached, looking entirely normal, until they let go together.

Which means the handful in the shower this morning was decided in a month you have probably stopped thinking about.

That delay is why people look in the wrong place and conclude there is no cause. There usually is one. It is just wearing last season's date.

Why nobody has found it yet

Here is the tension though.

When someone brings hair loss to an appointment, the usual test is a complete blood count and a TSH. Both come back normal, and the conversation ends with reassurance.

But a complete blood count measures hemoglobin, which is the last thing your body lets fall. Your iron stores can be genuinely at the floor while your blood count reads perfectly normal, because your body drains the warehouse to keep the shelves stocked.

And hair is not a survival priority. When resources get scarce, hair is one of the first things your body economises on, long before it will let hemoglobin drop.

So the sequence goes: stores empty, hair investment falls, hair sheds three months later, and the blood count is still entirely normal throughout.

The test that would have shown it is ferritin, which measures stores rather than circulation, and it is not on a standard panel unless somebody asks.

The same logic applies to thyroid. A TSH is the pituitary's instruction, not the hormone reaching the follicle, so it answers roughly a third of the question.

The causes, and what separates each

Read this as a map rather than a diagnosis. Two of these frequently run together, particularly iron and under-eating.

Low iron stores. The most common findable cause in women, and the one most often missed behind a normal blood count. Distinguishing marker: ferritin, read alongside hs-CRP so inflammation does not disguise a low value as an adequate one. An iron, TIBC and ferritin panel gives stores and transport together.

Thyroid, in either direction. Thyroid hormone regulates the hair cycle directly, so both underactive and overactive cause shedding. Distinguishing markers: a full thyroid panel with free T3, free T4 and antibodies.

A period of illness, fever, surgery or childbirth. Classic telogen effluvium triggers, and usually self-limiting once recovery is complete. Distinguishing sign: a clear event two to three months before the shedding began.

Rapid weight loss or severe restriction. A physiological stressor plus low protein and low iron intake at once. Distinguishing sign: a diet or a training block in the relevant window. This one usually resolves on eating properly again.

Medications. A long list contributes, including some antidepressants, beta blockers, anticoagulants, retinoids, and hormonal contraceptives when started or stopped. Distinguishing move: check your list against the timeline, then raise it with your prescriber rather than stopping anything.

Pattern hair loss rather than shedding. If it is thinning at the crown or a receding hairline rather than diffuse shedding, that is a different condition with different treatments, and it is worth a dermatologist rather than a panel.

Patchy round bald spots, or a changed scalp. Not telogen effluvium. That needs a doctor promptly rather than a testing menu, and it is in the hedge below.

The ferritin question, honestly

Alright. This is the number everyone wants an answer about, so let me give you what the research actually measured.

A 2022 study in Cureus recruited 100 women with non-scarring alopecia and compared their serum ferritin against controls. Mean ferritin in the alopecia group was 20.47 against 27.87 in controls, a statistically significant difference at p equals 0.005. The authors concluded that iron stores are an independent hazard for alopecia in non-menopausal women.

So the direction is established. Lower iron stores track with hair loss in women, measured rather than assumed, and that is a solid basis for testing ferritin and correcting it when it is low.

Building on that, dermatology practice commonly works to get ferritin above roughly 30 to 50 ng/mL in someone who is shedding, and many root-cause practitioners aim higher, on the reasoning that a follicle running a years-long growth cycle wants reserve rather than a number scraping the floor.

Where exactly your own line sits is a clinical judgement, made against your symptoms and the rest of your iron panel rather than read off a chart. That is why the person reading it matters as much as the number.

The practical version is straightforward either way. If your ferritin is low, correct it, and that is worth doing regardless of your hair since stores also drive energy, temperature and cognition. If it is comfortably high, look elsewhere on the list.

And test before supplementing, always. Iron is one of the few things where guessing carries real downside, because your body has no good way to shed an excess.

Where the honest hedge goes

I am not a doctor and I am not diagnosing anyone, and hair loss is one of the areas where getting the type right matters most.

Some presentations are not telogen effluvium and need a doctor promptly rather than a lab menu. Patchy round bald spots point at alopecia areata. Any redness, scaling, pain, or a scalp that looks changed points toward scarring alopecia, where follicles can be permanently lost and early treatment genuinely matters. Do not test-and-wait on those.

I also want to set an honest expectation on timelines, because this is where people lose heart. If your ferritin is low and you correct it, rebuilding stores takes three to six months. Then shedding settles. Then regrowth becomes visible, another three to six months after that. The hair you are losing today was decided months ago and the hair you are growing today will not be visible for months.

That is slow and it is genuinely frustrating, and it is not a sign nothing is working.

Shedding that continues past six months without an identified cause deserves a dermatology referral rather than another round of supplements.

I am not saying iron is your answer. I am saying it is a variable, a common one in women, and a normal blood count does not rule it out.

So. Here is what I would actually do.

Tonight, at no cost. Count back three months from when the shedding started and write down what was happening. This costs nothing and it identifies the cause more often than any single test.

Also tonight. Check your medication list against that same window. Started or stopped anything?

Check your last blood work. If it shows a complete blood count and no ferritin, your iron stores have never been measured, whatever you were told about your levels.

When you test, order stores rather than just the count. An iron, TIBC and ferritin panel with hs-CRP alongside, plus a full thyroid panel with free T3 and antibodies. Add vitamin D3 and B12 with folate.

Eat enough protein. Hair is largely protein, and low intake is a common quiet contributor alongside restriction. This is free and it helps regardless of what the tests show.

If it is patchy, or the scalp looks changed, see a doctor now. Not a panel. That is a different condition and the timeline matters.

The bigger project. Take the results to a good functional medicine doctor, and get a dermatology referral if shedding runs past six months.

None of this has to happen this week. But tonight you can write down what was happening three months ago.

You are not falling apart. You are a body that put hair low on the priority list during a month when something else needed the resources, and is only now showing you the receipt.

Your body is not broken. It is blocked. And often the block is an empty iron store behind a normal blood count, decided one season and delivered the next.

Go count back three months.