Quick answer: Telogen effluvium is heavy, all-over hair shedding that usually starts around 2 to 3 months after a shock to the body, such as an illness, an operation, a bereavement or a crash diet. The British Association of Dermatologists says the shedding phase lasts about 3 to 6 months and then new hair grows. It usually settles on its own, but it can come back if a cause like low iron is not found and fixed.
If your hair started coming out in handfuls a few months after something difficult, this post is for you. It explains why the delay happens, what a normal timeline looks like, and what you can do while you wait.
What telogen effluvium is
Every hair on your head goes through a cycle. It grows for years, then rests, then falls out so a new hair can push through in the same follicle.
According to the British Association of Dermatologists (BAD) leaflet on telogen effluvium, about 85% of scalp follicles are growing at any one time and about 15% are resting before they shed. In telogen effluvium (often shortened to TE), the resting share rises to 30% or more. So a much bigger batch of hairs falls out than usual, all at roughly the same time.
Alopecia UK puts normal shedding at up to 100 hairs a day and says some people with TE may lose up to 300 a day. If you are not sure whether your own shedding is normal, our guide on how much hair loss is normal walks through it.
The good news: the follicles are not damaged. They have simply been pushed into the resting phase early, all together.
Why the shedding starts months after the stress
This is the part that confuses most people. You were ill in January, you felt better by February, and then in April your hair starts falling out. It feels random. It isn't.
When the body goes through a big shock, a large number of growing hairs switch into the resting phase at once. Alopecia UK says the resting phase lasts 2 to 4 months before the hair sheds. That is why the hair loss shows up later: the hairs were "told" to stop growing at the time of the illness, but they only let go when the resting phase ends.
The BAD leaflet says shedding can begin around 3 months after a trigger. A 2020 review of the medical literature in the journal Cureus gives a similar window of about 2 to 3 months, and says hair loss linked to a new medicine usually starts after about 12 weeks of taking it.
So if you are trying to work out what caused your shedding, count back roughly 2 to 4 months.
Common triggers for hair shedding after illness or stress
The BAD and Alopecia UK both list similar triggers. Between them they include:
a severe illness or infection, especially one with a high fever
surgery or physical trauma
major emotional stress, such as a bereavement or a relationship breakdown
rapid weight loss or extreme dieting (Alopecia UK also mentions weight loss drugs)
childbirth and other big hormone changes, including stopping the contraceptive pill
starting a new medicine
iron deficiency and thyroid problems
Not every case has an obvious cause. The BAD says that for 1 in 3 people diagnosed with telogen effluvium, no cause can be found.
If you want a wider view of why hair falls out, including causes that are not TE, see why is my hair falling out: 10 causes.
What it looks and feels like
TE usually starts suddenly. You notice more hair in the shower drain, on your brush, or on your pillow. The thinning is spread across the whole scalp, so you won't usually see a bald patch. Your ponytail may feel thinner, or your parting may look a bit wider.
The BAD notes that some people also get a tender or odd-feeling scalp (doctors call this trichodynia, which just means scalp discomfort). Otherwise, there are usually no other symptoms.
Patchy bald spots, a receding hairline, or redness and scaling on the scalp point to something else. Those need checking.
Telogen effluvium timeline: will the hair grow back?
For most people, yes. The BAD says TE usually resolves completely without treatment, and the 2020 Cureus review reports that acute TE settles in about 95% of cases.
Here is a rough timeline based on the sources above:
The trigger happens (illness, operation, shock, diet).
Around 2 to 3 months later, shedding starts.
The heavy shedding phase lasts about 3 to 6 months, according to the BAD.
New hair grows. Alopecia UK says TE typically resolves within 6 to 9 months as the hair cycle returns to normal.
Getting back your full thickness and length takes longer. The BAD says it can take many months, and Alopecia UK says it depends partly on how long your hair is.
One sign of recovery is short new hairs coming through. The Cureus review notes shorter, regrowing hairs at the front of the scalp in cases that have settled. They can stick up a bit around your hairline and parting.
When shedding lasts longer than 6 months
If heavy shedding goes on past 6 months, the BAD calls it chronic telogen effluvium. The Cureus review adds that chronic TE is seen mostly in middle-aged women and tends to come and go.
The BAD also says TE can come back if an underlying cause, such as iron deficiency, is not treated, and that it can sit alongside or bring forward a diagnosis of male or female pattern hair loss. So long-running shedding is worth getting looked at properly.
Telogen effluvium treatment: what helps
There is no pill that switches TE off. The BAD is direct about this: taking medication does not speed up hair regrowth. Most people need no treatment, because the hair grows back by itself once the trigger has passed.
What you can do is find and fix anything that is keeping it going, and look after the hair you have while it recovers.
Get the right blood tests
Both the BAD and Alopecia UK say blood tests can help rule out other causes, with thyroid problems and iron deficiency the two they name. The Cureus review says management starts with removing the trigger, correcting any deficiency, and checking your medicines.
Your GP is the person to arrange these. Our bloods checklist lists what to ask about, so you go in prepared.
Be gentle with your hair
The BAD suggests avoiding harsh brushing, heated styling tools, bleaching and relaxing treatments, and tight hairstyles while you are shedding. It also says a balanced diet with enough iron and protein may help, and that stopping smoking may help too.
Cover it while it grows
If your scalp is showing, the BAD mentions camouflage fibres or sprays and volumising shampoos. Wigs are rarely needed for TE, but are available on the NHS with a consultant's prescription.
Minoxidil
Alopecia UK says a dermatologist may suggest topical minoxidil if regrowth is incomplete. Talk to your GP, pharmacist or dermatologist before starting it. The NHS hair loss page also advises seeing a GP to find the cause before paying for treatment at a commercial hair clinic.
When to see your GP
The NHS says to see a GP if you are worried about your hair loss. Based on the sources above, book an appointment if:
the shedding has gone on for more than 6 months
you see patches, a receding hairline, or a sore, red or scaly scalp
you recently started a new medicine (do not stop it without speaking to the prescriber)
the hair loss is affecting your mood or confidence
If the shedding is getting you down, tell your GP. The NHS notes they may be able to arrange counselling.
Frequently asked questions
Will telogen effluvium hair grow back?
In most cases, yes. The BAD says TE usually resolves completely without treatment, though full thickness can take many months to return.
How long does telogen effluvium last?
The BAD says the shedding phase lasts about 3 to 6 months. Alopecia UK says TE typically resolves within 6 to 9 months. Shedding beyond 6 months is called chronic TE.
Can stress alone cause hair to fall out?
Yes. Both the BAD and Alopecia UK list major psychological stress as a trigger. The hair loss usually starts 2 to 4 months after the stressful event.
Do I need treatment for telogen effluvium?
Usually not. The BAD says hair regrows on its own and medication does not speed it up. It is still worth asking your GP about blood tests for iron and thyroid, because an untreated cause can make TE come back.
Book a hair loss consultation in Belfast
If you are shedding heavily and want a calm, clear look at what is going on, we offer a £30 hair loss consultation at our Botanic Avenue clinic, and a full hair and scalp analysis. You can see all our treatments and prices online, or call 028 9096 4731.
Sources: British Association of Dermatologists: Telogen effluvium · Alopecia UK: What is telogen effluvium? · NHS: Hair loss · Asghar F et al. Telogen effluvium: a review of the literature. Cureus, 2020
About the author: Theresa Anthony is the trichologist at Tess Hair and Scalp Clinic, 77a Botanic Avenue, Belfast BT7 1JL, where hair loss treatment and a full hair salon sit under one roof. More about Theresa.
Written with AI help using the sources above, then checked by Theresa Anthony or her team before it went live.
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