In December 2025, a scientific team at UCLA advanced a major breakthrough in regenerative medicine with the development of PP405, a novel small molecule that can "reawaken" dormant hair follicles. This discovery centers on a previously unknown metabolic switch in hair follicle stem cells (HFSCs), allowing them to exit their resting phase and restart the growth cycle in as little as one week of topical application. The breakthrough lies in how the molecule alters the way hair cells process energy