White birch sap reduced melanin production in lab tests and showed minimal irritation compared to common skin-lightening ingredients like hydroquinone and kojic acid. The ingredient worked by suppressing genes involved in melanin creation, suggesting it could be an alternative for people sensitive to traditional brightening agents.

Researchers tested white birch sap on mouse melanoma cells and zebrafish larvae to measure how well it inhibited tyrosinase (the enzyme that creates melanin) and whether it caused irritation. They also checked gene expression to understand how the ingredient worked.

Funding not disclosed in abstract