TELOGEN EFFLUVIUM ASSOCIATED WITH WEIGHT-LOSS MEDICATIONS: PATHOPHYSIOLOGICAL MECHANISMS AND CLINICAL EVIDENCE

Abstract

Telogen effluvium is the leading cause of diffuse non-scarring alopecia and is characterized by the premature transition of hair follicles from the anagen phase to the telogen phase in response to various systemic stimuli. In recent years, the increasing use of weight-loss medications, particularly GLP-1 receptor agonists and dual GIP/GLP-1 receptor agonists, has been accompanied by a growing number of reports of hair loss, raising interest in the underlying pathophysiological mechanisms and clinical implications of this association. In this context, the present study aimed to conduct a narrative literature review on the association between telogen effluvium and the use of weight-loss medications, emphasizing the underlying pathophysiological mechanisms, predisposing factors, clinical characteristics, diagnostic aspects, and contemporary prevention and management strategies. This narrative review adopted a descriptive, analytical, and interpretative approach, based on studies retrieved from the PubMed/MEDLINE, SciELO, Scopus, Web of Science, and Embase databases, including clinical trials, observational studies, systematic reviews, meta-analyses, clinical guidelines, and experimental studies published between 2020 and 2026. The findings demonstrated that the association between weight-loss medications and telogen effluvium is multifactorial and is predominantly related to the metabolic adaptations induced by rapid weight loss, including caloric restriction, negative energy balance, macro- and micronutrient deficiencies, hormonal changes, and metabolic stress, rather than to a direct pharmacological effect on the hair follicle. Semaglutide and tirzepatide accounted for the greatest number of reported cases of hair loss; however, the magnitude of weight reduction appears to be the primary determinant of telogen effluvium development. Nevertheless, important limitations remain, including methodological heterogeneity among studies, the lack of standardized diagnostic criteria, and the scarcity of prospective investigations capable of distinguishing the relative contributions of weight loss and direct pharmacological effects on the hair cycle. It is concluded that telogen effluvium associated with weight-loss medications is predominantly a consequence of the physiological adaptations to rapid weight reduction, highlighting the importance of clinical and nutritional monitoring during obesity treatment and the need for future studies to establish evidence-based preventive and therapeutic strategies.