Karlie Hyeonjeong Koo is the founding Head of Design at Endo Health, where she leads design for Glow, an AI voice coach for weight loss and chronic care whose users are 98% women. Her work addresses a defining challenge of modern femtech: how conversational AI can build trust, motivation, and lasting behavior change in women's everyday health. Glow is profitable, with 7-figure ARR, 500,000+ downloads, and more than 12,000 kg of user weight loss to date, and is backed by a16z Speedrun, General Catalyst, and angels Anne Wojcicki (23andMe), April Koh (Spring Health), and Albert Lee (MyFitnessPal). Across her career, Karlie has built deep UX design expertise across healthcare, from brain-computer interfaces to 3D medical simulation. Her design work has been exhibited internationally and featured in Vice, Dezeen, and Designboom.