New RIFM study confirms robustness of critical skin sensitization protocol
7.2.25
A new study published in Dermatitis® confirms that the Research Institute for Fragrance Materials, Inc. (RIFM)’s Confirmation of No Induction in Humans (CNIH) protocol remains scientifically sound, even with the adoption of a more sensitive challenge method.
The study, “Updates to the Research Institute for Fragrance Materials, Inc. Confirmation of No Induction in Human Test Standard Protocol”, evaluated whether switching from a 24-hour to a 48-hour challenge patch, which is more in line with clinical dermatology practices, would impact the validity of RIFM’s more than three decades of human patch-testing data.
“This was a crucial pilot study,” said lead author Maura Lavelle, a scientist supporting RIFM’s Skin Sensitization Safety Assessment and Research Programs. “We needed to ensure that evolving our protocol wouldn’t invalidate over 30 years of carefully conducted studies. The findings give us that confidence.”
RIFM tested 19 fragrance materials, including major components of natural complex substances (NCS), on 2,317 human subjects using both 24-hour and 48-hour challenge patch protocols. The results showed no significant difference in sensitization outcomes between the two methods.
“Even though the 48-hour patch is more sensitive, the results aligned remarkably well with our existing data,” said Anne Marie Api, PhD, RIFM’s President. “This means we can enhance our alignment with clinical practice without losing the continuity or reliability of our historical safety assessments.”
The study reinforces RIFM’s commitment to continuously refining safety science while maintaining the value of existing data. It was conducted at the recommendation of the Expert Panel for Fragrance Safety, an independent panel comprising internationally recognized academic scientists, including dermatologists, pathologists, toxicologists, and environmental scientists, who review and must approve of all RIFM’s studies before submission to the peer-reviewed literature.
The full article is available via Dermatitis: https://doi.org/10.1089/derm.2025.0125.