Telogen Effluvium and Metabolic Stress in Modern Weight Loss Interventions: A Narrative Clinical Review

Telogen effluvium (TE) is a common nonscarring alopecia precipitated by systemic stress, nutritional deficiencies, or rapid metabolic change. With the rise of novel weight-loss therapies, especially glucagon-like peptide-1 receptor agonists (GLP-1 RAs) such as semaglutide and tirzepatide, as well as bariatric surgery, hair loss has become an increasingly reported adverse event in clinical practice. This narrative review examines TE as an emerging complication of weight-loss interventions. While micronutrient deficiency remains a recognized factor, accumulating evidence highlights the role of systemic homeostatic disruption, rapid weight reduction, and endocrine shifts in triggering hair shedding. Pharmacological interventions with GLP-1 RAs and surgical approaches such as bariatric procedures are evaluated for their effects on hair follicle cycling, with emphasis on metabolic stress, protein-energy balance, and lean body mass preservation. The review proposes that TE in these contexts is a clinical marker of transient systemic disequilibrium rather than permanent follicular damage.