If a study shows a fragrance ingredient can cause “adverse effects” in a lab, why is it still considered safe for me to use in my daily products?
As a toxicologist specializing in repeated dose and reproductive health, I often encounter this concern. The answer lies in a principle established centuries ago by the father of toxicology, Paracelsus:
“All things are poison, and nothing is without poison; only the dose permits something not to be poisonous.”
In modern science, we call this the distinction between hazard (an adverse effect observed at a particular dose) and risk (the likelihood of harm). The identification of hazards is required by regulatory agencies (such as the CLP Regulation under the European Commission), which means researchers must test at massive dose levels to actually induce adverse effects. Keep in mind that even substances like water can be hazardous at high doses. These doses used are often thousands of times higher than what consumers would ever encounter, highlighting the importance of considering fragrance exposure, or how much a person comes into contact with, when it comes to making safety decisions. Fortunately for fragrances, only a tiny amount is needed for people to detect them, because humans have an excellent sense of smell.
Putting Dose into Perspective
RIFM recently collaborated with North American and European academic experts on a peer-reviewed study titled “The difference between hazard and risk: the dose range prevalent in toxicological studies vs real life fragrance exposure,” which translates these laboratory doses into real-world scenarios.
We looked at common ingredients like benzaldehyde (found in almonds) and p-cymene (found in raspberries). To reach the “No Observed Adverse-Effect Level” (NOAEL, the highest-tested dose where science shows no harm occurs), a person would need to consume:
- 83,000 almonds every single day, for life.
- 153,778 raspberries every single day, for life.
What This Means for Your Fragrance
When we translate these lab doses to fragrance use, the numbers are equally staggering. To reach that same safe threshold for benzaldehyde, you would need to apply 138,330 sprays of perfume every day. In reality, even the most “loyal consumer” (someone in the 95th percentile of fragrance use) is only exposed to about 0.011 mL of benzaldehyde from all their products combined over an entire year. That is roughly equivalent to just 0.2 drops per year.
Safety by Design
In RIFM’s work assessing the safety of fragrance ingredients for reproductive and developmental health, we apply significant safety buffers to ensure the amount of an ingredient in your products is many times lower than any level that showed an effect in a study. Using advanced exposure modeling, we ensure that, while a hazard may exist at astronomical doses, the risk to you at real-world levels remains negligible.
Read the full study: doi.org/10.1016/j.yrtph.2026.106063
Watch: Fragrance Safety Explained: Why Scientists Say You Don’t Need to Worry