Telogen Effluvium

Telogen Effluvium

Telogen effluvium is a reversible kind of widespread hair shedding. A physical or emotional stressor shifts more scalp hair follicles than usual out of the active growth phase (anagen) and into the resting phase (telogen). About 2-3 months after the stressor, those follicles let go of their hairs, and shedding becomes visibly heavier. The condition resolves on its own: the follicles return to the growth phase, and hair density usually recovers within 6-12 months once the stressor has passed.

Common triggers include rapid or large weight loss, severe illness, surgery, childbirth, major emotional stress, suddenly stopping estrogen-containing medicines, and some nutrient deficiencies (notably iron, zinc and vitamin D). Diagnosis is clinical, supported by a positive hair pull test in which more than 10% of pulled hairs come out in the telogen phase.

In obesity drug treatment, telogen effluvium has been reported with all the GLP-1-class drugs, including semaglutide and tirzepatide, and is likely to be reported with retatrutide once its long-term Phase 3 safety data are fully described. The cause is most likely the rapid weight loss itself rather than a direct effect of the drug on hair follicles, the same pattern seen after bariatric surgery and very-low-calorie diets.

Treatment is mainly reassurance and time. Eating enough protein (typically 1.2-1.6 g/kg of ideal body weight per day), taking iron and vitamin D if levels are low, and not cutting calories harder than the medicine already does can help recovery. Topical minoxidil is sometimes used, but its effect in this setting is limited. Hair density usually returns to baseline within several months once weight stabilizes.