Scientists have identified a vital protein that helps protect hair follicle stem cells (HFSCs) and enables adult hair regeneration.

Published in March 2025 in Nature Communications, their research reveals how MCL-1 acts as a ‘cellular bodyguard’ for activated HFSCs. In this study, the team used mouse models to show that deleting the MCl-1 gene led to rapid death of activated HFSCs and a complete block in hair regrowth after induced hair removal. 

Interestingly, quiescent (inactive) HFSCs were unaffected by the absence of MCL-1. It was only when the cells were called into action that they succumbed to stress and died – unless MCL-1 was present. 

The researchers also discovered that MCL-1 is regulated by the ERBB signaling pathway, which is known to promote stem cell activation and hair growth. This connection highlights a potential target for future treatment: boosting ERBB signaling or MCL-1 activity could enhance stem cell survival and promote hair regeneration.