A shedding event triggered by physical stress — illness, surgery, sudden weight loss, severe emotional stress, certain medications, or hormonal shifts. Almost always temporary. Almost always resolves on its own within twelve months.
Hair grows in cycles. Each follicle goes through three phases: anagen (active growth, usually two to seven years), catagen (a brief transition phase), and telogen (resting, ~three months) before shedding the old hair and beginning a new growth cycle. At any given time, roughly 85–90% of your hair follicles are in anagen and 10–15% in telogen.
Telogen effluvium happens when a triggering event — physical or emotional stress, illness, major surgery, sudden weight loss, certain medications, hormonal shifts (postpartum, perimenopause, thyroid changes) — pushes a higher-than-normal percentage of follicles simultaneously into telogen. Two to three months after the trigger, those follicles release their hairs all at once. That’s the shed.
The clinical picture: diffuse thinning across the entire scalp, increased shedding in the brush and shower, often visible at the part line. The hair is not lost — it’s released by follicles that are about to start new growth cycles.
Major stress event. Bereavement, divorce, severe work stress over months. The shed often appears two to three months after the peak of the stress.
Illness or surgery. Significant fever, hospitalisation, major surgery, COVID-19. The body diverts resources away from non-essential systems including hair growth; the shed appears two to three months later.
Postpartum. Sharp estrogen drop after delivery — see the postpartum hair loss page for detail.
Thyroid disorders. Both hyperthyroidism and hypothyroidism can trigger telogen effluvium. Bloodwork (TSH, T3, T4) is part of any workup for unexplained shedding.
Iron deficiency. Low ferritin is a common contributor, particularly in menstruating women. Replenishing iron usually resolves the shed.
Crash dieting or rapid weight loss. Caloric restriction below maintenance for several weeks can trigger the shed.
Medications. Beta-blockers, retinoids, anticoagulants, some antidepressants, and chemotherapy are common pharmaceutical triggers.
Telogen effluvium is not a surgical condition. Hair transplant on someone in active telogen effluvium would be a mistake — the underlying issue isn’t a missing follicle, it’s a temporary disruption to the hair cycle. Wait it out, treat the underlying cause, and the hair returns.
You should see a doctor (or send us photos) if: 1. The shed hasn’t resolved at twelve months — that suggests something else is going on. 2. The pattern of loss is changing from diffuse to concentrated. 3. Other symptoms have appeared (fatigue, weight changes, cycle irregularity) that point to thyroid or other systemic causes.
If you’re past the twelve-month mark and worried that what looked like telogen effluvium has revealed an underlying androgenetic pattern, send photos. Dr. Jones will tell you what he sees, in writing.
Send photos for an honest read. Dr. Jones reviews personally — and refers to bloodwork or trichology if those come first.