A widely shared skincare trend that focuses on rosemary and its extract now has scientific backing. A JCI Insight study from Penn researchers found that a natural compound in rosemary leaves may enhance wound healing and lessen scarring.
“Most skin injuries scar, causing lasting issues,” said senior author Thomas Leung, MD, PhD. “Rosemary extract, especially carnosic acid, may promote true skin regeneration.” We currently lack reliable methods to achieve this in humans.
Penn undergraduate Jiayi Pang (left) and Penn PhD candidate Emmanuel Rapp Reyes (right) discovered that rosemary may promote wound healing without leaving scars.
A Social Media Trend Sparks Scientific Inquiry
The project originated from trends on TikTok and Instagram. After seeing many creators promote rosemary for skin repair, Pang and Rapp Reyes consulted Leung to verify the claims. Their questions sparked a series of lab investigations.
“We suspected the online buzz had merit because rosemary contains abundant antioxidants,” said Pang, co–lead author. “But to truly understand its potential, we needed to demonstrate its healing effects and identify the mechanism behind them.”
In experiments with mice, the researchers developed a cream containing carnosic acid, a naturally occurring antioxidant most abundant in rosemary. The cream accelerated wound healing and supported the regrowth of structures like hair follicles, oil glands, and cartilage. They also discovered that the compound activated a skin nerve receptor called TRPA1, previously associated with scar-free healing. When the cream was applied to mice lacking TRPA1, the regenerative benefits disappeared.
“Thyme and oregano can trigger TRPA1, but rosemary is the strongest and safest,” said Rapp Reyes, co–lead author. “Some substances, such as mustard oil and imiquimod, also activate TRPA1 but often cause irritation, unlike rosemary.”
Benefits Occur Only at the Application Site
The team found that rosemary’s regenerative benefits act only where the carnosic acid cream is applied. Applying it to distant skin areas didn’t improve healing, showing its effects are purely local.
The Penn researchers advise consulting a healthcare provider before using rosemary in skincare but hope its accessibility will encourage further studies on its potential for treating wounds and reducing scarring.
“If rosemary in your skincare routine seems to help, it likely does,” Leung said. “I’m proud that the young scientists who led this project pursued answers to questions that arose from their everyday experiences.”
Read the original article on: Sciencedaily
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