Comparing Facial Aging Between Identical Twins With 3D Imaging

Overview

Identical twins share the same genes, which makes them a powerful way to study how lifestyle and environment - rather than genetics - affect how faces age. This study builds on a landmark 2009 twin study by using modern three-dimensional (3D) facial imaging, which measures facial shape and volume precisely instead of relying on regular photographs. The study will also look at whether use of GLP-1 weight-loss medications (such as semaglutide or tirzepatide), sometimes associated with facial changes informally called "Ozempic face," is related to measurable differences in facial aging. The study will enroll adult identical twin pairs attending the Twins Days Festival in Twinsburg, Ohio, in August 2026. Participation takes about 30 minutes and happens in a single visit at the festival study booth. Each twin will complete a questionnaire about lifestyle, environment, and medical history (such as sun exposure, smoking, sleep, and medication use) and have a 3D image of their face taken with a non-contact camera system. There is no treatment, no medication, no blood draw or biological sample, and no follow-up visit. Researchers will then compare facial measurements within each twin pair to learn which lifestyle and environmental factors are linked to visible facial aging.

This is a prospective, observational, single-site study conducted at the Twins Days Festival, Twinsburg, Ohio (August 8-9, 2026). The design revisits the 2009 identical-twin facial aging study of Guyuron and colleagues with two methodological advances: replacement of standardized two-dimensional photography with three-dimensional facial surface imaging, permitting objective quantitative measurement of volumetric and topographic facial differences, and inclusion of GLP-1 receptor agonist and other rapid weight-loss medication exposure as a facial-aging variable that did not exist as a widespread exposure at the time of the original study. Participation is completed in a single session. After eligibility screening and written informed consent, each twin independently completes a structured questionnaire covering demographic, lifestyle, environmental, and medical-history domains, and undergoes standardized 3D facial surface imaging using a non-contact, non-ionizing optical system (approximately 1-2 minutes per participant). A staff member records Fitzpatrick skin type by brief visual assessment. No intervention is administered, no biological specimens are collected, no genetic testing is performed, and no individual results are returned. Zygosity is established by participant self-report, supported where available by prior DNA testing or physician confirmation; self-reported dizygotic or zygosity-uncertain pairs are recorded as such and analyzed separately from the confirmed monozygotic cohort. All data are recorded against coded participant identifiers. Because each monozygotic pair serves as its own genetic control, the primary analysis is of within-pair differences in quantitative 3D facial measurements, correlated with discordance in self-reported exposures. For the secondary objective, twin pairs discordant for self-reported GLP-1 receptor agonist use are compared with respect to midface and lower-face volume and contour. All measurement, extraction, and analysis of study data are performed by the study team on coded data.