Carnosic acid in topical rosemary extract enhances skin repair via TRPA1 activation

Mammalian skin wounds typically heal with a scar, characterized by fibrotic tissue that disrupts original tissue architecture and function. Therapies that limit fibrosis and promote regenerative healing remain a major unmet clinical need. Rosemary extract, particularly in the form of topical oils and creams, has gained widespread public attention for its purported wound-healing properties. However, its efficacy and mechanism of action remain poorly understood. We show in adult wound healing mouse models that an ethanol-based rosemary extract accelerates the speed of wound healing and mitigates fibrosis. Mechanistically, we identify that carnosic acid, a major bioactive component of rosemary leaves, activates the transient receptor potential ankyrin 1 (TRPA1) nociceptor on cutaneous sensory neurons to enhance tissue regeneration. Mice lacking TRPA1 in sensory neurons do not exhibit these pro-regenerative responses, confirming its role as a critical mediator. Together, these findings suggest that topical rosemary extract may represent an effective and accessible therapeutic approach to improve skin repair outcomes.