The Impact of GLP-1 Receptor Agonists on Hair: Beneficial Effects or Adverse Outcomes?

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly used for metabolic disorders, including type 2 diabetes mellitus (T2DM) and obesity. Reports to date have documented hair loss as an adverse event, while cases of hair regrowth have also been described [1]. This review evaluates evidence linking GLP-1RA use to hair outcomes. Following PRISMA guidelines, Embase and MEDLINE were searched (from inception to July 2025) using keywords specific to GLP-1RAs, “alopecia,” and “hair regrowth” (PROSPERO: CRD420251104356). Of 485 records identified, 10 full-text studies were included, comprising three retrospective cohort studies, four retrospective pharmacovigilance database studies, one living benefit-harm modeling study, one case–control study, and one case report. Risk of bias was assessed using Joanna Briggs critical appraisal tools. Hair loss type was mostly unspecified; however, 82 patients had centrifugal cicatricial alopecia (CCCA), 20 had androgenic alopecia (AGA), and 10 had telogen effluvium. Pharmacovigilance and modeling analyses examined a total of 920,890 adverse events, while cohort studies involved 382 patients. GLP-1RAs investigated included exenatide (27.1%, 170,880/630,671), dulaglutide (23.4%, 147,624/630,671), liraglutide (21.4%, 135,178/630,671), semaglutide (11.3%, 71,528/630,671), and tirzepatide (9.9%, 62,196/630,671). Of 626,894 patients on GLP-1RA for whom hair outcomes were reported, 9933 (1.6%) experienced hair loss, whereas 52 (0.008%) reported hair regrowth. Latency to hair loss or gender differences in alopecia events were not well described in studies. Clinical outcomes are summarized in Table 1. Multiple pharmacovigilance analysis studies identified a weak association between GLP-1RA use and hair loss, most commonly with semaglutide (reporting odds ratio (ROR), 1.24–2.46), followed by tirzepatide (ROR, 0.83–1.73) and liraglutide (ROR, 0.61–1.53). One disproportionality analysis of the US Food and Drug Administration's Adverse Event Reporting System (FAERS) (2022–2023 exclusively) revealed a positive signal for alopecia with semaglutide (ROR, 2.46) and tirzepatide (ROR, 1.73), suggesting that rates may exceed background reporting levels [2]. A review of several pharmacovigilance databases (FAERS, Vigibase, Eudravigilance, Database of Adverse Event Notifications (DAEN)) found that GLP-1RAs were associated with greater reporting of hair loss compared with other antidiabetic medications; however, disproportionality analyses were negative [3]. Hair regrowth was observed in select cases, and was variably defined as improvement in density, symptom resolution, or hair loss stabilization. A 57-year-old male with insulin resistance, obesity, and AGA experienced hair regrowth and normalized insulin resistance parameters within 6 months of initiating tirzepatide [1]. In 81 patients with CCCA, longer GLP-1RA duration and improved metabolic parameters (e.g., reduced HbA1c) were associated with scalp symptom improvement and/or hair regrowth in 58.0% of patients classified as “GLP-1RA responders”; however, explicit hair regrowth data were not reported; therefore, the number experiencing true hair gains is unknown [4]. Conversely, a cohort study of 283 GLP-1RA users visiting a hospital-based dermatology clinic for any dermatologic diagnosis found mixed outcomes: 32 patients (11.3%) had new-onset or worsening hair loss, while three patients (1.1%) with preexisting hair loss had resolution/stabilization following treatment [5]. Several mechanisms may contribute to the relationship between GLP-1RA use and hair loss or regrowth (Figure 1). Hormonal changes (particularly involving insulin and insulin-like growth factor), rapid weight loss, and the psychosocial stress of managing chronic disease may influence androgen production or the hair follicle cycle, precipitating AGA or telogen effluvium. Changes in dietary intake and potential nutritional deficiencies (i.e., vitamin D) secondary to altered satiety could potentially also contribute. Semaglutide and tirzepatide had the strongest associations with hair loss (ROR values > 1); however, without direct comparison, it is unclear whether their risk is greater than that of other GLP-1RAs. Several types of hair loss (e.g., CCCA, AGA) may improve with glycemic control. Causality cannot be inferred, and study limitations include the predominance of pharmacovigilance data, where reporting bias or differential GLP-1RA prescribing patterns may confound results. Further larger cohort studies are required to determine if certain hair loss disorders may benefit or worsen from GLP-1RA therapy. M.K.B., M.S.L., E.M. and T.K.-H. have no conflicts of interest to declare. J.D. has received honoraria from Pfizer and Vichy, has participated on advisory boards at Pfizer for payment, receives royalties from UpToDate, participates on the Board of Directors for the Scarring Alopecia Foundation, and is the active director of the Evidence Based Hair Fellowship Training Program. The data underlying this study are available in the article and in the supplemental material at https://data.mendeley.com/datasets/k7pydjb66f/1.

In recent years, the application of various light and laser devices in the treatment of different types of alopecia has been established. This systematic review aims to assess the efficacy and safety of laser therapy and phototherapy in cicatricial and non-cicatricial alopecia. A comprehensive search was conducted on PubMed, Scopus, Science Direct, and Google Scholar. Articles were evaluated across four subgroups: alopecia areata, androgenic alopecia, telogen effluvium, and cicatricial alopecia. Included studies were published in English or Persian between January 2010 and September 2023, focusing on interventional, cohort, or case series research that achieved a minimum score of 75% on the EBL checklist. Exclusion criteria encompassed animal and in vitro studies, review articles, case reports, duplicated or irrelevant research, as well as studies that did not meet the designated EBL score. Editorial letters and case studies were also excluded. Initially, 965 records were collected, resulting in the inclusion of 58 studies in the final review: 26 on alopecia areata, 26 on androgenic alopecia, five on cicatricial alopecia, and one on telogen effluvium. Narrow-band ultraviolet B, 308-nm excimer laser, and psoralen ultraviolet A therapy showed varying effectiveness; specifically, the excimer laser was notably effective for patients with shorter disease duration. In androgenic alopecia, erbium-glass and thulium lasers effectively increased hair density but showed a gradual decline posttreatment. Low-level light/laser therapy also increased hair density and diameter and exhibited potential benefits when used alongside minoxidil, but did not significantly enhance outcomes in telogen effluvium treatment. Light/laser therapy can serve as an additive treatment for cicatricial alopecia, particularly lichen planopilaris, but has limited efficacy in treating telogen effluvium. Overall, light/laser therapies exhibit a significant positive effect on increasing hair density and diameter across various alopecia types.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have recently gained widespread use among patients with type 2 diabetes mellitus or obesity, owing to their substantial impact in lowering blood glucose levels and reducing body weight. Apart from this, the FDA Adverse Event Reporting System (FAERS) identified several dermatological side effects, including hair loss, associated with the administration of GLP-1 RAs, prompting further research. This systematic review aimed to provide a comprehensive and up-to-date overview of hair loss related to the use of GLP-1 RAs. The search strategy utilized PubMed, SCOPUS, and Web of Science databases using key terms: (("GLP-1 receptor agonist"[Mesh] OR "GLP1- receptor agonist"[tiab] OR "Glucagon-Like Peptide 1"[tiab] OR "GLP-1 agonist"[tiab] OR semaglutide[tiab] OR liraglutide[tiab] OR tirzepatide[tiab] OR exenatide[tiab] OR dulaglutide[tiab]) AND (hair loss[Mesh] OR alopecia[tiab] OR "telogen effluvium"[tiab] OR "alopecia areata"[tiab] OR hair[tiab]) ). Including all primary English studies, the hair loss outcomes associated with the use of GLP-1 RA in adults were reported without time restriction. A total of five relevant studies were included in this review, encompassing 2,905 adult patients who received subcutaneous trizepatide mainly on a weekly basis. The study yielded conflicting findings, with some indicating significant improvement and hair regrowth, while others reported hair loss as an adverse dermatological event. Further research is recommended to clarify the relationship between GLP-1 RAs and alopecia.

Vitamin D status in scarring and nonscarring alopecia

A Human Folliculoid Microsphere Assay for Exploring Epithelial– Mesenchymal Interactions in the Human Hair Follicle

p75 Neurotrophin Receptor-Mediated Signaling Promotes Human Hair Follicle Regression (Catagen)

Context: Trichoscopy is a non-invasive, bedside diagnostic tool used to classify alopecia. It is instrumental in distinguishing between non-cicatricial (non-scarring) and cicatricial (scarring) alopecia, aiding in disease classification, prognosis, and treatment decisions. This modality reduces the need for skin biopsies by identifying specific trichoscopic patterns that correlate with disease activity, severity, and potential for hair regrowth, especially in cicatricial alopecia. It also helps select biopsy sites in diagnostically challenging cases. Objectives: The review discusses trichoscopy of various forms of non-scarring and scarring alopecia. Methods: The authors searched the literature on non-cicatricial and cicatricial alopecia and their clinical and trichoscopic characteristics in various research databases. Results: Non scarring alopecia includes androgenetic alopecia (AGA), female pattern hair loss (FPHL), telogen effluvium, alopecia areata (AA), tinea capitis, trichotillomania (TTM), and tractional alopecia. In AGA and FPHL, trichoscopy identifies hair thickness variability and signs like yellow dots and vellus hair, which aid in assessing disease severity and surgical candidacy for hair transplants. Alopecia areata shows unique trichoscopic features like exclamation mark hairs and yellow dots, which help gauge disease activity. Tinea capitis and TTM also display distinct trichoscopic markers, facilitating accurate diagnosis without invasive biopsies. In scarring alopecias such as discoid lupus erythematosus (DLE), lichen planopilaris (LPP), and frontal fibrosing alopecia (FFA), trichoscopy reveals inflammation-related features like Perifollicular hyperkeratosis, erythema, and the absence of follicular ostia, guiding treatment and biopsy decisions. It helps distinguish FFA from conditions like AGA and AA by showing characteristic features like concentric Perifollicular erythema and loss of vellus hair. Morphea and pseudopelade of Brocq each display hallmark trichoscopic features. Morphea, in its early stages, responds well to immunosuppressive treatments, whereas pseudopelade of Brocq, being an end-stage condition, shows limited responsiveness to medical interventions. Conclusions: Overall, this review article emphasizes the importance of trichoscopy as a bedside tool for narrowing differential diagnoses and guiding clinical management in various types of alopecia. It highlights the need for ongoing knowledge of trichoscopic signs to facilitate prompt diagnosis and tailored treatment for both non-scarring and scarring alopecia.

Time to Follow the Evidence: Glycemic Control and Cardiovascular Benefits of New Diabetes Medications

Human hair follicles, which are distributed in various and specific sites of the body, appear to have an inherited susceptibility for androgen-dependent growth. Beard, axillary, and frontal scalp dermal papilla cells (DPC) were recently shown to possess the characteristics of androgen target cells. These DPC show strong expression of androgen receptors, and the expression of type II 5alpha reductase is restricted to beard and frontal scalp DPC. These findings suggest that DPC mediate the signals of androgen to follicular epithelial cells in a paracrine fashion. We developed an in vitro co-culture system using DPC and keratinocytes (KC) to characterize the mode of androgen action in human hair follicles. Androgen significantly stimulated the proliferation of KC co-cultured with beard DPC, indicating that beard DPC produce androgen-dependent diffusible growth factors. Insulin-like growth factor-I was identified as one of the androgen-dependent paracrine growth factors produced by beard DPC. We also identified the inhibitory role of androgen on the growth of KC co-cultured with DPC from androgenetic alopecia (AGA) when the DPC were transfected with an expression vector encoding the androgen receptor. This growth suppression of KC was mediated by transforming growth factor-beta1 (TGF-beta1) derived from DPC of AGA, suggesting that TGF-beta1 is a paracrine mediator for AGA.

An Albumin-Exendin-4 Conjugate Engages Central and Peripheral Circuits Regulating Murine Energy and Glucose Homeostasis

Overweight and obesity seriously damages human health. The World Health Organization estimates that 1.5 billion adults were overweight in the year of 2011. Of this overweight population, over 200 million men and nearly 300 million women were obese. At least 2.8 million adults die each year as a result of being overweight or obese. A total of 44% of the diabetes burden and 23% of the ischemic heart disease burden are attributable to overweight and obesity1. More than 70% of diabetic patients will experience macrovascular disease that is strongly associated with overweight and obesity2. Type 2 diabetes is continuing to be the leading cause of cardiovascular disorders, end-stage renal disease, blindness and amputations. Therefore, effective interventions designed to achieve weight reduction are a critical part of type 2 diabetes management to prevent the development of microvascular and macrovascular complications. However, the majority of diabetic patients gain rather than lose weight, particularly during intensifying glycemic control. Many antidiabetic agents are currently available for glycemic control, but less than 50% of type 2 diabetic patients can reach their therapeutic goal. This problem might be related to the side-effects of antidiabetic agents, including hypoglycemia (insulin, sulfonylureas and repaglinides) and bodyweight increase (insulin, thiazolidinediones, sulfonylureas and lifestyle). Action to Control Cardiovascular Risk in Diabetes (ACCORD) initially aimed to investigate the effects of intensive glycemic control on cardiovascular end-points in type 2 diabetes patients at high risk of cardiovascular events, but a 22% increase in total mortality was observed in this group, mainly driven by cardiovascular mortality. The explanation for higher cardiovascular (CV) mortality remains unclear, but hypoglycemia and weight gain were responsible for the adverse outcomes3. These results make a great impact on the concept of hyperglycemic management in type 2 diabetes, and patients should receive treatment that enables them to safely achieve an ideal glycemic control without a risk of hypoglycemia or higher gain in bodyweight. Hyperglycemia in type 2 diabetes has been well investigated and can be attributed to increased hepatic glucose production, defective insulin-stimulated glucose disposal in target tissues, abnormal islet cell function and hypersecretion of glucagon. Antihyperglycemic agents are directed to one or more of the aforementioned defects of type 2 diabetes, or to modify physiological processes relating to appetite or to nutrient absorption or excretion. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are secreted from the intestines, and can enhance the endogenous secretion of insulin induced by meal ingestion and inhibit glucagon secretion, thereby improving glucose homoeostasis. Notably, GLP-1 also suppresses food intake and appetite. Abnormalities in this incretin system were found in type 2 diabetes. GLP-1 receptor (GLP-1R) agonists were recently introduced as a new treatment for patients with type 2 diabetes. Several clinical trials have shown that GLP-1R agonists can effectively and safely lower hyperglycemic parameters by dependently stimulating insulin secretion and inhibiting glucagon secretion. They have a rather low risk of hypoglycemia because of their mode of action. GLP-1 can slow down gastric emptying after a meal. Additionally, GLP-1 binds to its receptor on hypothalamic neurons and stimulates satiety by directly acting on its receptor. All clinical trials of GLP-1R agonists have shown that agonists could lead to weight reduction in type 2 diabetes. Recently, Vilsbøll et al.4 carried out a systematic review with meta-analyses to determine whether treatment with GLP-1R agonist resulted in weight reduction in overweight or obese patients with type 2 diabetes. Adult participants with a body mass index of 25 or higher were included in these randomized controlled trials. They received exenatide twice daily, exenatide once weekly or liraglutide once daily for at least 20 weeks. Control interventions were placebo, oral antidiabetic drugs or insulin. Vilsbøll et al. carried out a random effects meta-analysis of 3,395 participants randomly assigned to GLP-1R agonists and 3,016 assigned to control groups for the change of bodyweight from 21 trials. They found that the mean change in bodyweight was larger for patients with GLP-1R agonist treatment than those in the control groups (weighted mean difference −2.9 kg; 95% confidence interval −3.6 to −2.2; Table 1). In the overall analysis, GLP-1R agonists improved glycemic control, with an increase in patients who achieved the therapeutic glycated hemoglobin (HbA1c) goals. Additionally, GLP-1R agonists had beneficial effects on systolic and diastolic blood pressure, and plasma concentrations of cholesterol. Importantly, they also found that GLP-1R agonists were not associated with hypoglycemia, despite the side-effects of nausea, diarrhea and vomiting. The present meta-analysis provides convincing evidence that GLP-1R agonists should be considered in patients with diabetes who are obese or overweight4. Several once-weekly GLP-1R agonists have been found to decrease HbA1c, and fasting and postprandial hyperglycemia. They can also greatly reduce bodyweight. More recently, the position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) for the management of hyperglycemia in type 2 diabetes was published. In this statement, metformin is the preferred first agent if it is not contraindicated or if tolerated. If metformin alone does not achieve or maintain a HbA1c target over 3 months, a second oral agent, GLP-1R agonist or basal insulin, would be added. When a two-drug combination is not yet or no longer achieving the glycemic target, this statement suggests adding a third non-insulin agent, including GLP-1R agonist5. Some studies have shown advantages from the addition of GLP-1R to a combination therapy. Over 80% of individuals with type 2 diabetes are overweight or obese. GLP-1R agonists show their beneficial effects on weight loss and safety without hypoglycemia in type 2 diabetes. The systematic review with meta-analysis carried out by Vilsbøll et al. convincingly confirms the place of GLP-1R agonists in guidelines for management of hyperglycemia in type 2 diabetes.

Emerging evidence suggests a potential association between glucagon-like peptide-1 (GLP-1) receptor agonists and alopecia. Drug-induced hair loss is a recognized adverse effect linked to various medications, including chemotherapeutics, immunosuppressants and certain biologics.1 Recently, semaglutide and tirzepatide—two GLP-1 receptor agonists widely used in managing type 2 diabetes mellitus and obesity—have been implicated in hair loss. A study by Godfrey et al.2 conducted a disproportionality analysis using data from the FDA Adverse Event Reporting System (FAERS) between 2022 and 2023. The authors identified elevated reporting odds ratios (RORs) for alopecia associated with semaglutide (ROR: 2.46; 95% CI: 2.14–2.83) and tirzepatide (ROR: 1.73; 95% CI: 1.42–2.09). These findings suggest a potential link between these medications and hair loss, an adverse event not previously reported in clinical trials.2, 3 Interestingly, this association was observed with the once-weekly GLP-1 agonists semaglutide and tirzepatide but not with the older, once-daily injectable liraglutide. The mechanisms underlying this association remain speculative. Previous studies have demonstrated the expression of GLP-1 receptors in murine hair follicles, although their precise role within the hair growth cycle is not clearly defined.4 This raises the possibility that GLP-1 agonists could influence hair growth cycles. However, human data are lacking, necessitating further research. Alternatively, the rapid weight loss induced by these agents may precipitate telogen effluvium (TE), a form of non-scarring alopecia characterized by diffuse hair shedding often seen following metabolic stress.1 TE is well documented in patients experiencing significant weight loss, such as after metabolic and bariatric surgery.5 The metabolic changes and nutritional deficiencies associated with rapid weight reduction may disrupt the hair growth cycle, leading to increased shedding. Clinically, this potential adverse effect warrants attention. Patients initiating GLP-1 agonists like semaglutide or tirzepatide should be informed about the possibility of hair loss, especially those with a history of alopecia or concerns about hair appearance. Monitoring for signs of TE and providing nutritional support may mitigate this risk. Since TE is generally reversible, reassurance and patient education are essential. Clinicians are advised to include GLP-1 agonists in the medication history of patients presenting with hair loss, discuss the possibility of hair shedding when initiating these therapies and ensure patients maintain adequate nutrition to mitigate the risk of TE. Further investigations are needed to elucidate the relationship between GLP-1 agonists and alopecia. Prospective studies assessing hair loss incidence in patients undergoing treatment with these agents, controlling for weight loss and nutritional status, would provide more definitive evidence. Exploring the expression and role of GLP-1 receptors in human hair follicles could also shed light on potential direct effects. Such studies could help identify risk factors that predispose certain individuals to alopecia with these medications or guide clinical dose adjustments. In conclusion, the study by Godfrey et al.2 highlights a possible association between GLP-1 agonists and alopecia, underscoring the importance of pharmacovigilance in detecting rare adverse events. Clinicians should remain vigilant, discuss potential side effects with patients and consider monitoring hair health during treatment with semaglutide and tirzepatide. Ongoing research is essential to confirm these findings and guide clinical practice. None. Michael G. Buontempo has no conflicts to disclose. Bianca T. Santos has no conflicts to disclose. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

Preoperative considerations of new long-acting glucagon-like peptide-1 receptor agonists in diabetes mellitus

Aims/hypothesisOur aim was to assess treatment discontinuation, reinitiation and switching between drugs within the same drug class for glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors in individuals with type 2 diabetes.MethodsWe used data from nationwide registers in Sweden to perform separate analyses for all patients with type 2 diabetes who filled a first prescription of a GLP-1 receptor agonist or an SGLT2 inhibitor between 2017 and 2021. Patients were considered to be on treatment for the period during which prescriptions were refilled before the estimated end date of the most recent prescription, including a 90-day grace period, i.e. the time allowed between and after prescriptions before treatment is considered as discontinued. We used the Aalen–Johansen estimator to estimate cumulative incidences of discontinuation and reinitiation, and Fine–Gray sub-distribution hazard models to assess the association of clinical variables with the risk of discontinuation.ResultsAmong 73,895 new users of GLP-1 receptor agonists, the cumulative incidence of treatment discontinuation was 23.6% at 1 year and 38.5% at 3 years. Among patients who discontinued, the cumulative incidence of treatment reinitiation was 41.1% at 1 year and 57.4% at 3 years after discontinuation. Among 113,207 new users of SGLT2 inhibitors, the cumulative incidence of treatment discontinuation was 27.9% at 1 year and 45.9% at 3 years, with a cumulative incidence of reinitiation of 40.4% at 1 year and 55.7% at 3 years after discontinuation. When varying the grace period between 60 days and 365 days, treatment discontinuation rates at 3 years ranged from 23.3% to 43.6% among GLP-1 receptor agonist users and from 28.8% to 50.6% among SGLT2 inhibitor users. The proportion of patients who had ongoing treatment, regardless of previous discontinuation episodes, ranged between approximately 70% and 80% for both drugs during a 1–5 year period after treatment initiation across analyses using various grace periods. In terms of switching, 22.9% of the GLP-1 receptor agonist users and 2.1% of the SGLT2 inhibitor users switched between drugs within the same drug class. Patient characteristics associated with treatment discontinuation were similar for GLP-1 receptor agonists and SGLT2 inhibitors, although the association between higher BMI and a lower likelihood of treatment discontinuation was stronger for GLP-1 receptor agonists.Conclusions/interpretationApproximately half of type 2 diabetes patients who had started using GLP-1 receptor agonists or SGLT2 inhibitors had discontinued treatment within 5 years of follow-up. However, more than half of those who discontinued treatment subsequently reinitiated treatment, such that the proportion with ongoing treatment was approximately 70–80% for both drugs during a 1–5 year period after treatment initiation. This suggests that the proportion of patients with long-term use of the medications is larger than indicated by analyses focusing on treatment discontinuation. Patient characteristics associated with treatment discontinuation were similar for GLP-1 receptor agonists and SGLT2 inhibitors.Graphical

Introduction: Hair loss is one of the most frequent complaints for which patients see a dermatologist. The three most common causes of hair loss in women are telogen effluvium, alopecia areata and female pattern hair loss. Objectives The aim of this study was to investigate haemoglobin, iron profile and thyroid function tests in women with telogen effluvium, alopecia areata and female pattern hair loss. Materials and Methods: This was a hospital based cross sectional study conducted at the Department of Dermatology and Venereology, Nepal Medical College and Teaching Hospital (NMCTH). We recruited female patients with telogen effluvium, alopecia areata or female pattern hair loss who presented to our outpatient department between June 2019 and July 2020. Clinical and demographic data were collected and haemoglobin, serum iron profile and thyroid function investigated. Results: A total of 80 patients were recruited in the study period. The most common diagnosis was telogen effluvium (49, 61.25%) followed by alopecia areata (18, 22.5%) and female pattern hair loss (13, 16.25%). Although mean haemoglobin levels were within normal limits, inadequate ferritin levels for normal hair cycle were found in 77.55% of patients with telogen effluvium, 88.89% with alopecia areata and 84.61% with female pattern hair loss. Thyroid abnormalities were less commonly observed with more than 75% of the patients being euthyroid. Conclusion: Haemoglobin levels are not representative of true iron status in females with acquired alopecia. We therefore recommend investigating iron profile in all females with telogen effluvium, alopecia areata or female pattern hair loss.