Telogen Effluvium: Why Your Hair Is Falling Out After Stress, Illness or Weight Loss

Telogen Effluvium: Why Your Hair Is Falling Out After Stress, Illness or Weight Loss

You notice it in the shower drain. On your pillow. Wrapped around your hairbrush in numbers that feel alarming. If you've been through a stressful period, recovered from an illness, or lost weight quickly in the past few months, what you're seeing likely has a name: telogen effluvium.

It's one of the most common causes of sudden, diffuse hair shedding in adults — and understanding why it happens is the first step toward doing something about it.

What Is Telogen Effluvium?

Telogen effluvium (TE) is a temporary form of hair loss caused by a disruption to the natural hair growth cycle. It was first described and named by dermatologist Albert Kligman in 1961 and remains one of the most studied patterns of non-scarring hair loss today.¹

To understand why it happens, it helps to know how your hair normally grows:

• Anagen phase (growth): Lasts 2–6 years. Roughly 85–90% of your follicles are here at any given time.
• Catagen phase (transition): A brief 2–3 week period where the follicle shrinks.
• Telogen phase (resting/shedding): Lasts around 3 months, after which the hair is shed. Normally about 10–15% of your follicles are in this phase.

In telogen effluvium, a physiological shock causes a large proportion of anagen follicles to abruptly shift into telogen simultaneously. When those hairs reach the end of the resting phase — typically 2 to 3 months later — they shed all at once.²

This delay is why many people are confused: the hair falling out now is reacting to something that happened months ago.

What Triggers Telogen Effluvium?

TE is not random. It's your body's response to a stressor significant enough to interrupt normal cellular processes. The most common triggers include:

1. Physical or Emotional Stress

Severe psychological stress — bereavement, major life changes, prolonged anxiety — can push follicles into premature telogen. The body essentially deprioritises hair growth during perceived crisis states.³

Physical trauma, including surgery, accidents, or high fever (including from infections like COVID-19 or dengue), is equally disruptive. Studies document TE onset 8–12 weeks after acute febrile illness.⁴

2. Rapid Weight Loss or Restrictive Dieting

One of the most underappreciated triggers. Crash diets, very low-calorie protocols, and weight-loss surgery can all precipitate TE through a combination of caloric restriction and micronutrient depletion.

Low ferritin (stored iron) is particularly implicated. Research by Harrison and Bergfeld at the Cleveland Clinic found that suboptimal ferritin — even without clinical anaemia — was consistently associated with TE in women.⁵ Zinc, vitamin D, and protein deficiencies have also been independently linked to diffuse shedding.⁶

3. Hormonal Shifts

Childbirth is one of the most common TE triggers. During pregnancy, elevated oestrogen prolongs the anagen phase, keeping more hair on the head. When oestrogen drops postpartum, a mass shift into telogen follows — typically peaking at 3–4 months after delivery.²

Thyroid dysfunction (both hypothyroidism and hyperthyroidism) can also cause or prolong TE. It's one reason thyroid-stimulating hormone (TSH) is routinely tested when evaluating hair loss.⁷

4. Nutritional Deficiencies Without Dieting

You don't have to be on a diet to be deficient. Poor dietary diversity, gastrointestinal malabsorption, vegetarian or vegan diets without adequate supplementation, and heavy menstrual bleeding can all silently deplete the nutrients your follicles need.

How to Recognise It

Telogen effluvium has a distinct clinical profile:

• Diffuse shedding across the scalp (not patchy baldness)
• Increased hair on pillow, in shower drain, or on brush — often 200–300+ hairs per day (normal is ~50–100)
• Onset 2–3 months after a trigger event
• Hair that comes out with a small white bulb attached (telogen root)
• Thinning most noticeable at the temples and crown, though the hairline is usually preserved

The hair pull test — a gentle tug on 40–60 hairs — is a simple clinical indicator. More than 10% of pulled hairs detaching easily suggests active TE.⁸

Getting a Diagnosis

If you're experiencing diffuse shedding, it's worth seeing a dermatologist or trichologist to rule out other causes. A thorough evaluation typically includes:

• Full blood panel: Complete blood count, serum ferritin, iron studies, TSH, zinc, and vitamin D
• Clinical history: Identifying the timing of the trigger (usually 2–3 months prior)
• Trichoscopy: Dermoscopy of the scalp to assess follicle miniaturisation and distinguish TE from androgenetic alopecia
• Pull test

Telogen effluvium can coexist with androgenetic alopecia, and distinguishing the two matters for treatment planning.

How Long Does It Last?

Acute telogen effluvium — triggered by a specific, resolvable event — typically resolves within 3 to 6 months once the trigger is addressed. Hair regrowth follows, though it may feel thinner during the transition period as shorter, regrowing hairs catch up.⁹

Chronic telogen effluvium is defined as diffuse shedding lasting more than 6 months. It's more common in women aged 30–60 and may cycle through phases of active shedding and relative stability. The prognosis is still generally positive, but identifying persistent triggers — ongoing stress, subclinical deficiencies, thyroid irregularity — becomes important.²

What Can Help?

Treatment focuses on the underlying cause:

• Address nutritional deficiencies: Supplementing iron (with ferritin as the target marker), zinc, and vitamin D where deficient is the foundational step. Work with a physician to establish baseline levels first.
• Prioritise dietary protein: Hair is primarily keratin. Adequate protein intake (~1.2–1.6g/kg body weight) supports follicle function.
• Manage stress: Easier said than done, but techniques that reduce cortisol — regular exercise, sleep hygiene, psychological support — have documented impact on hair cycle physiology.
• Topical minoxidil: Clinically supported for promoting hair regrowth; often recommended off-label while waiting for the underlying cause to resolve.⁶
• Scalp-supportive care: Gentle, sulphate-free formulations that minimise mechanical stress on fragile regrowing strands.

A Note on Hair Density After TE

Many people find that even after active shedding stops, hair feels thinner than before. This is partly because shorter regrowing hairs haven't reached full length yet, and partly because cumulative shedding episodes — especially in those with a family history of androgenetic alopecia — can unmask underlying thinning. Supporting scalp health consistently during recovery matters.

Frequently Asked Questions

Q: How do I know if my hair loss is telogen effluvium or something else? Telogen effluvium typically presents as diffuse shedding across the whole scalp 2–3 months after an identifiable trigger, without bald patches. Patchy loss, a receding hairline, or shedding without a preceding trigger should be evaluated by a dermatologist to rule out alopecia areata, androgenetic alopecia, or scalp conditions.

Q: Can telogen effluvium cause permanent hair loss? In most cases, no. TE is a reversible condition. Once the trigger resolves and the hair cycle resets, regrowth occurs. However, prolonged or repeated episodes — particularly alongside a genetic predisposition to androgenetic alopecia — can contribute to cumulative thinning over time.

Q: How much shedding is normal? Losing 50–100 hairs per day is within the normal range. In active TE, daily shedding can reach 200–300+ hairs. If you're consistently losing large amounts and noticing visible thinning, that warrants a clinical evaluation.

Q: Can stress alone cause hair to fall out? Yes. Psychological stress is a well-documented trigger for telogen effluvium. Significant emotional events — job loss, bereavement, relationship breakdown — can be sufficient to shift follicles into premature telogen. The hair loss typically appears 2–3 months after the stress peak.

Q: Will my hair grow back after weight loss? In most cases, yes — once nutritional deficiencies are corrected and weight stabilises, the hair cycle resumes. The key is ensuring ferritin, iron, zinc, vitamin D, and protein intake are adequate during and after the weight loss period.

Q: How long until I see regrowth? After the trigger resolves, new growth typically becomes noticeable within 3–6 months. Full density recovery can take 12–18 months, as regrowing hairs need time to reach visible length.

The Bottom Line

Telogen effluvium is your body's delayed stress response — and the 2–3 month lag between trigger and shedding is often what makes it so confusing. The good news is that for most people, it's temporary and reversible.

If you're seeing diffuse hair shedding and suspect a link to recent stress, illness, or dietary changes, the priority is identifying and addressing the root cause early.

A Zoey doctor can help you identify likely triggers, assess your shedding pattern, and recommend evidence-based treatment options. Visit zoey.sg →

References

1. Kligman AM. Pathologic dynamics of human hair loss. I. Telogen effluvium. Arch Dermatol. 1961;83:175–198.
2. Malkud S. Telogen Effluvium: A Review. J Clin Diagn Res. 2015;9(9):WE01–WE03. doi:10.7860/JCDR/2015/15160.6492
3. Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus. 2020;12(5):e8320. doi:10.7759/cureus.8320
4. Grover C, Khurana A. Telogen effluvium. Indian J Dermatol Venereol Leprol. 2013;79(5):591–603. doi:10.4103/0378-6323.116731
5. Harrison S, Bergfeld W. Diffuse hair loss: its triggers and management. Cleve Clin J Med. 2009;76(6):361–367. doi:10.3949/ccjm.76a.08080
6. Phillips TG, Slomiany WP, Allison R. Hair Loss: Common Causes and Treatment. Am Fam Physician. 2017;96(6):371–378.
7. Shrivastava SB. Diffuse hair loss in an adult female: approach to diagnosis and management. Indian J Dermatol Venereol Leprol. 2009;75(1):20–27.
8. Rebora A. Telogen effluvium: a comprehensive review. Clin Cosmet Investig Dermatol. 2019;12:351–358. doi:10.2147/CCID.S200618
9. Trüeb RM. Telogen effluvium. In: Trüeb RM, Tobin DJ, eds. Aging Hair. Springer, Berlin, Heidelberg. 2010.