Absorption As you’ve read earlier in this article, monograph reform— specifically, the back and forth regarding which ingredients need more testing—has been confusing news to the general public. Part of the reason for more testing relates to a May 2019 FDA-sponsored study that also made headlines: “Application of four commercially available sunscreens under maximal use conditions resulted in plasma concentrations that exceeded the threshold established by the FDA for potentially waiving some nonclinical toxicology studies for sunscreens. The systemic absorption of sunscreen ingredients supports the need for further studies to determine the clinical significance of these findings. These results do not indicate that individuals should refrain from the use of sunscreen.” The filters in this study were three of the six most commonly used organic filters and one of the “new” filters: avobenzone, oxybenzone, octocrylene, and ecamsule. Some in the general public were now confused AND scared. Phrases like “systemic absorption” and “plasma concentrations that exceeded the threshold” seemed incompatible with the idea that sunscreen with these ingredients was beneficial. Other people were unfazed, knowing these sunscreen ingredients have been in use for decades. And it was helpful when media reported the language accurately: The concentrations did not exceed safety thresholds; they exceeded the threshold for waiving toxicology studies. FDA messaging attempted to explain the nuance: “The fact that an ingredient is absorbed through the skin and into the body does not mean the ingredient is unsafe.” But the overall messaging was not clear or robust. Media coverage often made the situation more confusing. In January 2021, the FDA announced the results of a followup study of absorption of the active ingredients in certain sunscreen filters into the body’s bloodstream. This study confirmed the absorption found in the first study and included all six commonly used organic filters: avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate.
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