Homosalate, a common sunscreen ingredient, disrupted hormone balance in male fish at relatively low concentrations—lowering testosterone and raising estrogen levels while damaging the liver. When combined with avobenzone (another UV filter), the hormonal disruption got worse. The study suggests these effects happen through interference with the body's steroid hormone production system.

Researchers exposed male zebrafish and human hormone-producing cells to homosalate alone and mixed with avobenzone, then measured changes in testosterone, estrogen, liver health, and gene activity related to hormone production.

Funding not disclosed in abstract