hairlossWhat is telogen effluvium?
Every hair follicle cycles between a long growing phase (anagen) and a resting phase (telogen), after which the resting hair falls out and a new one starts. Normally about 85% of scalp follicles are growing and about 15% are resting (DermNet). The American Academy of Dermatology (AAD) says it is normal to shed 50 to 100 hairs a day (AAD).
In telogen effluvium, a stressor pushes a larger-than-usual share of growing hairs into the resting phase at the same time. A few months later those hairs fall out together. The follicles are not damaged, which is why the hair can grow back. The result is diffuse thinning across the whole scalp rather than bald patches or a receding hairline.
Common triggers
The AAD lists these common stressors behind excessive shedding:
- Losing 20 pounds or more
- Giving birth
- Major stress, such as caring for a sick loved one, divorce or losing a job
- A high fever, or recovering from an illness, especially one with a high fever
- Having surgery
- Stopping birth control pills
Other recognized causes include thyroid disorders, nutritional deficiency and certain medicines (DermNet). A 2019 review notes that stopping estrogen-containing pills, minoxidil or finasteride can itself set off shedding about 3 to 4 months later (Rebora, Clin Cosmet Investig Dermatol, 2019). The AAD warns not to stop any medicine you suspect is causing hair loss without first talking to your doctor. According to the International Society of Hair Restoration Surgery (ISHRS), about a third of cases have no identifiable cause (ISHRS).
The shedding timeline
The delay is what confuses most people. Because hairs rest for weeks to months before they fall, shedding usually starts 2 to 4 months after the trigger (DermNet), often when you have already recovered from the illness or event. After a high fever the gap can be shorter, around 2 to 6 weeks (Rebora, 2019).
Once the body readjusts, the AAD says shedding stops and hair typically regains its normal fullness within 6 to 9 months. Length takes longer: the ISHRS notes that scalp hair grows only about a quarter to half an inch a month, so it can take 18 months or more before your hair looks the way it did. If the stressor continues, shedding can continue too.
Acute vs chronic telogen effluvium
| Feature | Acute | Chronic |
|---|---|---|
| Duration | Less than about 6 months | More than 6 months, sometimes years (Rebora, 2019) |
| Trigger | Usually a clear event 2 to 4 months earlier | Often no obvious trigger |
| Who | Any age, any sex | Most often otherwise healthy women aged 30 to 60 (DermNet) |
| Course | Usually resolves once the trigger is gone | Can wax and wane; needs a fuller medical work-up |
The ISHRS cites self-remission in about 95% of patients within several months of the stressor ending, and recommends a broader medical evaluation if symptoms last longer than 6 months.
Telogen effluvium vs pattern hair loss
Telogen effluvium thins hair evenly, including the sides and back. Pattern hair loss (androgenetic alopecia) is gradual, follows a pattern at the temples, crown or part line, and involves hairs becoming finer over time. Alopecia areata usually causes sudden smooth patches; see our alopecia areata guide. A 2019 review notes that thinning above the ears, an area pattern loss usually spares, points toward chronic telogen effluvium, while many fine (vellus) hairs point toward pattern loss (Rebora, 2019).
The two can overlap. DermNet notes that an episode of telogen effluvium can unmask an underlying tendency to pattern hair loss, so if your hairline or crown does not fully recover, our receding hairline guide and Norwood scale guide can help you describe what you see to a doctor.
How it's diagnosed
A dermatologist will ask about illnesses, life events, diet and medicines in the months before the shedding started, and examine the scalp. Common checks include:
- Pull test: gently tugging small groups of hairs to see how many come out easily.
- Wash test: collecting and counting hairs shed in one wash after 5 days without shampooing. More than 100 hairs suggests telogen effluvium (Rebora, 2019; ISHRS).
- Trichoscopy or a trichogram: looking at hairs under magnification. More than 25% resting hairs strongly suggests telogen effluvium (DermNet).
- Blood tests where appropriate, such as thyroid function and iron studies, to look for a treatable cause. A scalp biopsy is rarely needed.
Treatment and recovery
For most people, the treatment is time plus fixing the cause. DermNet describes acute telogen effluvium as self-correcting and recommends gentle hair care, a nutritious diet and treating any underlying hormonal, nutritional or scalp problem. Practical steps:
- Identify the trigger. Count back 2 to 4 months from when the shedding started.
- See a doctor or dermatologist if the shedding is heavy, lasts more than a few months, or comes with other symptoms such as fatigue, weight change or irregular periods.
- Avoid self-prescribing supplements. The 2019 review found no support for biotin or vitamin E for telogen effluvium, and links excess vitamin A and selenium to shedding.
- Ask about options for prolonged cases. The ISHRS mentions topical minoxidil, correcting nutritional deficiencies, PRP and low-level laser therapy for some patients. Talk to a doctor or dermatologist about whether any of these suits you.
- Look after your mental health. Shedding can cause real anxiety, and DermNet notes the psychological effects should not be ignored.
The angle most guides skip: telogen effluvium and hair transplants
Top-ranking guides explain the biology but rarely address a question people ask once they see hair in the drain: should I get a transplant? For telogen effluvium on its own, the answer is usually no. A 2024 review of pre-surgical considerations in hair restoration says telogen effluvium "tends to self-resolve without the need for hair restoration surgery," and that diffuse, unpatterned thinning does not respond well to transplantation (Tan, Yong & Wang, Plast Aesthet Res, 2024). The same review recommends ruling out causes such as iron deficiency and thyroid disorders, and suggests a blood count, thyroid panel and iron studies for women with apparent pattern loss.
Three practical points follow:
- Wait for the shed to settle. A good surgeon will want to see your hair after an episode has run its course, because the donor and recipient areas can look thinner than they really are.
- Surgery itself can trigger shedding. Transplanted hairs are normally shed after the procedure and start regrowing after 3 to 6 months, fully grown by 9 to 14 months (Tan et al., 2024). Some nearby native hairs can also shed temporarily, often called shock loss. Our hair transplant recovery guide covers what is normal.
- Treat the underlying pattern, if there is one. If telogen effluvium has unmasked pattern hair loss, that is the condition a transplant may address, and candidacy depends on donor supply and age. See our female hair transplant guide and best age for a hair transplant.
When to see a doctor
See a doctor or board-certified dermatologist if you are worried about how much hair you are losing, if shedding lasts longer than 6 months, if you see patches, scalp redness, scaling or pain, or if you have other symptoms that could point to a thyroid, nutritional or hormonal problem. The AAD notes that a dermatologist can tell whether you have shedding, hair loss or both, and that earlier treatment generally gives a better outlook.
Frequently asked questions
How long does telogen effluvium last?
Acute telogen effluvium usually starts 2 to 4 months after a trigger, and the AAD says hair typically regains its normal fullness within 6 to 9 months once the body readjusts. Regaining full length can take 12 to 18 months or longer. Shedding that lasts more than 6 months is called chronic and deserves a medical evaluation.
Will my hair grow back after telogen effluvium?
In most cases, yes. The follicles are not destroyed, and the ISHRS cites self-remission in about 95% of patients within several months of the stressor ending. Recovery can be incomplete if the trigger continues or if pattern hair loss is also present.
Can stress cause telogen effluvium?
Yes. The AAD lists major stress, such as caring for a sick loved one, divorce or losing a job, among the common triggers, along with high fever, childbirth, surgery, losing 20 pounds or more and stopping birth control pills.
How can I tell telogen effluvium from male or female pattern baldness?
Telogen effluvium causes sudden, even shedding across the whole scalp, including the sides. Pattern hair loss develops gradually at the temples, crown or part line, with hairs becoming finer. The two can coexist, so a dermatologist's exam is the most reliable way to tell.
Should I get a hair transplant for telogen effluvium?
Usually not. A 2024 review in Plastic and Aesthetic Research notes that telogen effluvium tends to resolve without surgery and that diffuse, unpatterned thinning does not respond well to transplantation. If an underlying pattern hair loss remains after the shedding settles, a hair restoration surgeon can assess whether you are a candidate.