"Just finding these metals isn't the issue; it's the levels that matter," principal investigator S. Katharine Hammond, professor of environmental health sciences at the University of California, Berkeley, said in a statement. "Some of the toxic metals are occurring at levels that could possibly have an effect in the long term."
The researchers tested 32 different lipsticks and lip glosses commonly found in U.S. drugstores and department stores.
The study, published in the journal Environmental Health Perspectives, found lead, cadmium, chromium, aluminum and five other metals, some of which were found at levels that could raise potential health concerns. Lipstick and lip gloss are of special concern because they are ingested or absorbed, bit by bit, by the individual wearing them, the study authors said.
The researchers developed definitions for average and high use of lip makeup based on usage data reported in a previous study.
Average use was defined as a daily ingestion of 24 milligrams of lip makeup per day, but those who slather on lip color and reapply it repeatedly could fall into the high use category of 87 milligrams ingested per day, Hammond said.
The average use of some lipsticks and lip glosses would result in excessive exposure to chromium, a carcinogen linked to stomach tumors and high use of these makeup products could result in potential overexposure to aluminum, cadmium and manganese as well, the study said.
The study authors said for most adults, there is no reason to toss the lip gloss in the trash, but the amount of metals found do signal the need for more oversight by health regulators, currently, there are no U.S. standards for metal content in cosmetics.
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