SOT Spotlight: Q&A with Chloe Stewart

Posted on Behalf of  Chloe Stewart

What is the title of your presentation?

Quantitative Risk Assessment Of Skin Sensitization Elicitation Following Use Of Shampoo Products Containing Formaldehyde Releasing Preservative DMDM Hydantoin

What was the scope of your research?

DMDM hydantoin (DMDMH) is formaldehyde-releasing preservative that is used in personal care products, including shampoos, to extend product shelf-life. DMDMH acts by releasing approximately 2% free formaldehyde in equilibrium with hydantoin. Although it has been deemed, “safe as used” by the Cosmetic Ingredient Review (CIR) Expert Panel, there have been allegations of hair loss following use of shampoo products containing this preservative in recent years. We conducted a quantitative risk assessment (QRA) in order to evaluate the potential risk of skin sensitization elicitation after the application and use of a shampoo product containing approximately 1% (w/v) DMDMH, the maximum allowable concentration found used in personal care product formulations.

What did you find?

After comparing the estimated daily dermal exposure or consumer exposure level to the acceptable exposure limit, we found that there was no expected elicitation of skin sensitization following use of a shampoo product containing 1% DMDMH (0.02% formaldehyde) for a typical use scenario among healthy individuals who are not previously sensitized to formaldehyde.

What are the next steps/what other research is needed?

This QRA considered DMDMH to be the only formaldehyde-releasing preservative present in the shampoo formulation (i.e., did not consider potential additive formaldehyde exposure), should other sources of formaldehyde be present, further evaluation would be appropriate. This framework can be utilized in future studies evaluating skin sensitization elicitation following exposure to other formaldehyde-releasing preservatives or sources of formaldehyde.