Homosalate, a common sunscreen ingredient, disrupted hormone balance in male fish by lowering testosterone and raising estrogen levels—effects that got worse when combined with avobenzone, another popular UV filter. The chemical appeared to interfere with the body's steroid hormone production system. Researchers note that long-term exposure effects in humans still need investigation.

Researchers exposed male zebrafish and human hormone-producing cells to homosalate and avobenzone—alone and in combination—then measured changes in testosterone, estrogen, hormone-related genes, and liver health.

Funding not disclosed in abstract