Ask a RIFM Scientist

Two people in lab coats having a discussion over a microscope and tablet
Headshot of Dan Selechnik

What does science tell us about using fragrance over time?

Dan Selechnik, PhD

Often, our body’s response to a single exposure or even a few exposures to an ingredient (what we call acute exposure) does not provide a complete picture of how the ingredient may affect us.

The “repeated dose” perspective examines the effects of frequent and regular ingredient exposures over a prolonged period. For example, we use fragrance products daily for most of our lives (what we call chronic exposure), so repeated dose studies better simulate real-life conditions. 

Repeated dose toxicity differs from studying endpoints like skin sensitization in that we are investigating an ingredient’s potential systemic rather than local effects.

Local refers to an ingredient’s effects on one particular organ or site, such as the skin or the lungs.

Systemic refers to an ingredient’s general effects on the body, such as changes to multiple organs.

We do this by measuring “ADME,” which stands for four aspects of how an ingredient interreacts with the human system over time: Absorption, Distribution, Metabolism, and Excretion.

Absorption refers to an ingredient’s potential to enter the body.

Distribution refers to where in the body an ingredient might travel.

Metabolism is a more complicated process wherein the body breaks down a substance to use and eliminate it. The substance may change its molecular structure during this process, and scientists refer to these new, temporary structures as metabolites.

Excretion refers specifically to the elimination of the ingredient.

Dan Selechnik, PhD, leads RIFM’s Repeated Dose Toxicity efforts.