Exhibit 99.1 Yatsen Announces Fourth Quarter and Full Year 2023 Financial Results Conference Call to Be Held at 7:30 A.M. U.S. Eastern Time on March 6, 2024 GUANGZHOU, China, March 6, 2024 – Yatsen Holding Limited ("Yatsen" or the "Company") (NYSE: YSG), a leading China-based beauty group, today announced its unaudited financial results for the fourth quarter and full year ended December 31, 2023. Fourth Quarter and Full Year 2023 Highlights • Total net revenues for the fourth quarter of 2023 increased by 6 ...