Telogen Effluvium: Stress-Related Hair Shedding

Telogen effluvium is a common, temporary type of hair shedding triggered by significant physical or emotional stress on the body — illness, surgery, childbirth, major weight loss, certain medications, or prolonged psychological stress. It’s one of the most frequently diagnosed causes of sudden, diffuse hair shedding, and the reassuring news is that it’s almost always reversible once the underlying trigger resolves.

It’s also been documented as a real, well-studied consequence of viral illness, including COVID-19 — published research found a meaningful share of COVID-19 patients reported increased hair shedding in the months following infection, consistent with how telogen effluvium follows any significant illness. It isn’t a symptom of the illness itself, but a delayed aftereffect of the body’s stress response to it.

Why it happens: the hair growth cycle

Hair grows in a repeating cycle: the anagen (growth) phase lasts several years, the catagen (transition) phase lasts about 10 days as the hair detaches from its follicle, and the telogen (resting) phase lasts roughly 60–90 days before the hair sheds naturally. Losing 70–150 hairs a day during normal telogen shedding is considered typical.

During significant physical or emotional stress, the body deprioritizes “non-essential” functions like hair growth, redirecting resources toward more immediately critical systems. This pushes a much larger-than-usual share of follicles into the telogen phase at once. Because there’s a lag between entering the resting phase and actually shedding, the increased hair loss typically becomes noticeable 2–3 months after the triggering event — which is why the connection to the original stressor is so often missed.

Acute vs. chronic telogen effluvium

Acute telogen effluvium is the more common, uncomplicated form. Shedding begins 6–8 weeks after the trigger and typically resolves within about six months once the underlying cause is addressed.

Chronic telogen effluvium persists longer — sometimes over a year — and is more likely when the underlying trigger (such as an unaddressed thyroid condition or ongoing nutrient deficiency) hasn’t been resolved. This form generally warrants dermatologist involvement to identify and treat the root cause.

Common triggers

• Prolonged physical or emotional stress – elevated cortisol redirects the body’s resources away from hair follicles.
• Illness and fever – including viral infections like COVID-19, flu, and other significant infections.
• Nutrient deficiencies – particularly iron, zinc, and vitamin D, along with protein and certain B vitamins.
• Pregnancy and postpartum hormonal shifts – commonly called postpartum telogen effluvium.
• Menopause – hormonal changes during this transition can trigger shedding.
• Certain medications – including some used for cancer treatment, tuberculosis, and hormonal contraception.
• Rapid or significant weight loss – particularly when combined with inadequate calorie or nutrient intake.
• Thyroid disorders and autoimmune conditions – both hypothyroidism and hyperthyroidism can trigger it.
• Major surgery or hospitalization – the physical stress of surgery and recovery is a recognized trigger.

Recognizing telogen effluvium

There’s no single defining symptom, but the pattern typically includes:

• Diffuse thinning across the scalp rather than a well-defined patch (which would point to a different condition, like alopecia areata).
• Increased shedding during washing or combing — noticeably more than the typical 70–150 hairs a day.
• A receding or widening part that develops over a period of weeks.
• In more extensive (chronic) cases, shedding beyond the scalp, including eyebrows or eyelashes.

How doctors diagnose it

A dermatologist typically combines several assessments to confirm telogen effluvium and rule out other causes:

• Hair pull test – gently pulling a small section of hair to count how many strands release and examine their structure.
• Wash test – counting hairs shed during a normal wash and comb.
• Scalp examination – checking for diffuse thinning versus patchy loss, and ruling out visible scalp conditions.
• Blood tests – commonly a complete blood count, thyroid function test, and vitamin D level, to identify an underlying deficiency or thyroid issue driving the shedding.

Treatment: addressing the underlying cause

There’s no single medication that treats telogen effluvium directly — the actual treatment is identifying and addressing whatever triggered it. Once the underlying cause (illness, deficiency, thyroid imbalance, medication, stress) is resolved, hair typically regrows on its own over the following months. Minoxidil, the one FDA-approved over-the-counter hair-loss treatment, is sometimes recommended alongside addressing the root cause to potentially support faster regrowth, though it isn’t a substitute for treating the actual trigger.

If a nutrient deficiency is confirmed by blood testing, targeted supplementation of the specific deficient nutrient (rather than a broad multivitamin approach) tends to be more effective. For a full, practical routine covering stress management, gentle hair care during shedding, and supporting nutrients, see our guide on regaining hair loss from stress.

When to see a dermatologist

See a dermatologist if shedding continues beyond six months, if hair loss is patchy rather than diffuse, or if you can’t identify a clear trigger — these patterns can point to a different underlying condition that needs its own diagnosis and treatment rather than the wait-and-support approach that works for straightforward telogen effluvium.