Quick definition: The telogen phase is the resting stage of the hair growth cycle. After growth (anagen) and transition (catagen), the follicle rests for about three months while the old hair stays in place, then sheds it as a new hair begins. About 10–15% of scalp hairs are in telogen at any time.
What is the telogen phase?
Telogen is the third of the main stages of hair growth. It follows anagen, the years-long growth phase, and catagen, the short transition in which the follicle shrinks and the hair detaches from its blood supply.
By the time a hair reaches telogen, it has become a "club hair": a fully keratinized strand with a small, rounded bulb at the root. It is no longer growing, but it stays anchored in the hair follicle until it is pushed out, often by a new anagen hair forming underneath. Some sources call this final release "exogen."
How long does the telogen phase last?
On the scalp, telogen typically lasts about three months. The NCBI StatPearls chapter on hair physiology notes the resting phase ranges from a few weeks for eyelashes to nearly a year for scalp hair, and Cleveland Clinic describes it as lasting up to four months.
"10 to 15% of all hairs on the body are in this resting phase" — StatPearls: Physiology, Hair
How much shedding is normal?
Because a steady slice of your hair is always finishing telogen, some daily shedding is expected. The American Academy of Dermatology says it's normal to shed between 50 and 100 hairs a day. You'll notice more on wash days simply because loose telogen hairs collect in the drain at once.
|
Stage |
What the follicle is doing |
Typical scalp duration |
|
Anagen |
Actively growing hair |
2–7 years |
|
Catagen |
Shrinking and detaching |
About 2–3 weeks |
|
Telogen |
Resting, then shedding |
About 3 months |
Telogen effluvium: when too many hairs rest at once
Telogen effluvium (TE) is the most searched term connected to this phase, and for good reason: it is a common cause of sudden, diffuse shedding.
"a form of nonscarring alopecia characterized by diffuse, often acute, hair shedding" — StatPearls: Telogen Effluvium
In plain terms, a stressor pushes a large number of growing (anagen) hairs into the resting phase early. Since telogen lasts a few months, the shedding shows up well after the trigger. StatPearls notes the triggering event usually happens about three months before shedding starts, though the gap can range from one to six months. Hair comes out evenly across the scalp rather than in patches, and "nonscarring" means the follicles themselves are not destroyed.
Common triggers
Dermatology references, including Cleveland Clinic and StatPearls, list triggers such as:
• High fever, severe infection, or major surgery
• Childbirth (postpartum shedding) and other hormonal shifts, including stopping birth control
• Significant psychological stress
• Crash dieting, rapid weight loss, or low protein intake
• Thyroid problems or iron deficiency
• Certain medications
StatPearls notes that collecting 100 or more hairs in 24 hours suggests TE, and that women tend to be more susceptible because of postpartum hormonal changes.
How long does telogen effluvium last?
For most people, acute TE is temporary. Cleveland Clinic says it usually lasts three to six months, and the AAD notes hair tends to regain its normal fullness within six to nine months once the trigger has passed. Regrowth takes time to become visible because new hairs start from the root. StatPearls also describes a chronic form with a more gradual onset, which calls for a closer look at ongoing causes.
When to see a doctor
Shedding that is sudden, heavy, patchy, lasts beyond a few months, or comes with other symptoms such as fatigue or weight changes should be evaluated by a board-certified dermatologist or your doctor. Telogen effluvium can look similar to other forms of hair loss, and underlying causes like thyroid disease, iron deficiency, or medication effects need a proper diagnosis. A dermatologist may do a gentle pull test, examine the scalp, or order blood work. No cosmetic product, including a light device, replaces that evaluation.
Telogen in beauty and personal care
Understanding telogen helps you read your own shedding more calmly and choose a sensible routine.
• Gentle handling. Resting hairs release easily, so rough brushing, tight styles, and aggressive towel-drying mostly speed up shedding that was going to happen anyway, and can add breakage.
• Realistic timelines. Any scalp or haircare routine takes months to show visible changes, because the cycle itself moves slowly.
• Scalp comfort. A clean, balanced scalp is a good foundation while hairs rest and new ones begin. See our entry on scalp coverage for how at-home scalp tools are designed.
• Nutrition. Adequate protein, iron, and other nutrients matter for hair; see our zinc glossary entry for why more isn't always better.
How Reseen fits in
Reseen's scalp tools are designed for a gentle, consistent routine that you can keep up through the slow pace of the hair cycle. Weave is a handheld light comb with 39 × 660nm red VIPE™ precision light emitters for a healthier-looking scalp and fuller-looking hair.
Halo, coming soon, is a wireless cap liner with 256 red and blue precision light points and 10- to 15-minute care modes. Both are cosmetic devices that support scalp health; they are not a treatment for telogen effluvium or any hair loss condition.
Frequently asked questions
How long does the telogen phase last?
On the scalp, telogen usually lasts about three months, though some sources describe up to four months. After that, the old club hair sheds and the follicle returns to anagen to grow a new hair.
Is telogen effluvium permanent?
Acute telogen effluvium is usually temporary, with shedding typically lasting three to six months and fullness returning within six to nine months after the trigger resolves. A chronic form exists, so persistent shedding should be checked by a dermatologist.
What causes telogen effluvium?
It is triggered by a physical or emotional stressor, such as high fever, surgery, childbirth, crash dieting, thyroid issues, iron deficiency, or certain medications. Shedding typically begins around three months after the event.
How many hairs a day is normal to lose?
The AAD says shedding 50 to 100 hairs a day is normal. If you are consistently losing noticeably more, or see thinning or bald patches, see a board-certified dermatologist.
Browse every term in the Reseen glossary.
Sources
1. Telogen Effluvium — Hughes EC, Syed HA, Saleh D; StatPearls, NCBI Bookshelf, 2024
2. Physiology, Hair — Hoover E, Alhajj M, Flores JL; StatPearls, NCBI Bookshelf, 2023
3. Do you have hair loss or hair shedding? — American Academy of Dermatology, accessed 2026
4. Telogen Effluvium: Symptoms, Causes, Treatment & Regrowth — Cleveland Clinic, accessed 2026
5. Hair Follicle: Function, Structure & Associated Conditions — Cleveland Clinic, accessed 2026
This article is for general education and is not medical advice. Reseen devices are cosmetic devices and are not intended to diagnose, treat, cure, or prevent any disease. If you have a skin or scalp condition, talk to a board-certified dermatologist.