Common Sunscreen Ingredients Absorbed Systemically

By Kelly Young

Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

Common active ingredients in sunscreen are absorbed into the blood at a level that warrants systemic safety testing on the products, FDA researchers report in JAMA.

Twenty-four healthy adults were randomized to one of four sunscreens (two sprays, one lotion, and one cream) containing various concentrations of avobenzone, oxybenzone, octocrylene, and ecamsule. Sunscreen was applied to 75% of the body surface 4 times a day for 4 days. Participants provided 30 blood samples over 7 days.

All participants had at least 0.5 ng/mL of the active ingredients in their blood on the first day of exposure. (This is the FDA's threshold at which products should undergo nonclinical toxicology testing, including for carcinogenicity.) During the trial, concentrations rose, suggesting accumulation. The maximum concentration of plasma avobenzone — the primary outcome — ranged from 1.8–4.0 ng/mL.

The authors call for additional research "to determine the clinical significance of these findings." They note: "These results do not indicate that individuals should refrain from the use of sunscreen."