Researchers at UCLA have identified a small molecule known as PP405 that can reactivate long-dormant hair follicles by changing how their cells produce energy. The compound acts as a metabolic switch, pushing inactive hair follicle stem cells into an active growth phase by increasing lactate production, a key signal for starting a new hair cycle. PP405 works by inhibiting the mitochondrial pyruvate carrier, a mechanism that normally keeps follicle stem cells in a resting state. By blocking this