Efficacy, Patient-Reported Outcomes, and Safety in Male Subjects Treated With OnabotulinumtoxinA for Improvement of Moderate to Severe Horizontal Forehead Lines BACKGROUND Men represent a growing segment of the facial aesthetic market. OBJECTIVE To evaluate investigator-assessed efficacy, patient-reported outcomes, and safety after onabotulinumtoxinA treatment of forehead lines (FHL) in men. METHODS Subjects with moderate to severe FHL received onabotulinumtoxinA (frontalis: 20 U; glabellar complex: 20 U, with/without 24 U in crow's feet regions) or placebo in 6-month, double-blind periods of 2 pivotal trials. Results for men were pooled. RESULTS Men comprised 12% (140/1,178) of subjects. Day 30 male responder rates for achieving at least 1-grade Facial Wrinkle Scale (FWS) improvement at maximum eyebrow elevation and at rest were 98.2% and 93.3%, respectively; a significant difference in responder rates was maintained versus placebo (p < .05) through Day 150. Despite men having proportionately more severe FHL at baseline, 81.8% and 79.8% achieved Day 30 FWS ratings of none or mild at maximum eyebrow elevation and at rest, respectively (p < .05); significance versus placebo was maintained through Day 120. Men reported high satisfaction rates and improved psychological impacts. No new safety signals were detected. CONCLUSION Standard dosing and administration of onabotulinumtoxinA significantly improved static and dynamic FHL appearance, despite men having proportionately more severe FHL at baseline. Men reported high satisfaction and appearance-related psychological impact improvements. Address correspondence and reprint requests to: Terrence C. Keaney, MD, SkinDC, 1525 Wilson Boulevard, Suite 125, Arlington, VA 22209, or e-mail: terrencekeaney@gmail.com Supported by Allergan plc, Dublin, Ireland. Editorial support for this article was provided by A. Drinkwater of Peloton Advantage, Parsippany, New Jersey, and was funded by Allergan plc. T.C. Keaney has served on advisory boards and speakers' bureaus and serves as a consultant for Allergan plc. M. Cavallini and C. Leys serve as investigators for Allergan plc. A. Rossi serves as a consultant and on an advisory board for, and has received honoraria from, Allergan plc. A. Drinkwater is an employee of Peloton Advantage, who received funding from Allergan plc for medical editing and editorial support. S. Manson Brown, J.K. Garcia, and C. Mao are employees of Allergan plc and may own stock/options in the company. © 2019 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. All rights reserved.