"This preliminary study of metal content in lip products suggests potential public health concerns," wrote the authors of the new study, published May 2 in Environmental Health Perspectives, a government-funded journal.
For the study, researchers at the University of California, Berkeley's School of Public Health enlisted a group of 12 girls between the ages of 14 and 19 who were part of an Asian youth group and lived in low-income neighborhoods of Oakland, Calif. They were asked to record the brands and product names of all lipsticks and lip glosses they regularly carry and use at home.
The researchers then took this list to stores and purchased the products, 32 in all (8 lipsticks, 24 lip glosses).
Back at the lab, researchers conducted spectrometry tests to determine the contents of the lipsticks. They found detectable levels of lead, cadmium, chromium, aluminum and five other metals in the products.
Lead, a neurotoxin, was found in 24 products -- 75 percent of all tested -- and all examined products contained the metals manganese, titanium and aluminum.
Half the products contained lead in concentrations higher than 0.1. parts per million cap the U.S. Food and Drug Administration places on candy frequently eaten by small children.
Concentrations of metals varied greatly across products. For example, one product had the highest chromium concentration (9.72 ppm) and the second highest concentrations of cadmium, manganese, and lead (2.16, 35.3, and 1.25 ppm, respectively). The researchers did not find a clear pattern to predict toxin levels in terms of brands, color, whether it was lip gloss or lipstick or in the cost of the products, which ranged from about $6 to $24.
The researchers also analyzed potential risk for toxin exposure by comparing how often the lip products are used to the concentration of the toxins found in the products. Results were measured in term of average use and heavy use.
They determined the estimated chromium intake from 10 products tested exceeded acceptable daily intake levels when measuring average use. Chromium is a known human carcinogen, according to the researchers, that has been linked to lung cancer and stomach tumors through inhaling the metal or swallowing it.
Heavy use of lip products could lead to too much aluminum exposure for one of the products tested, and too much chromium for 22 products tested, and potentially dangerous levels of manganese in 7 of the products tested.
Cadmium, another metal found, is a carcinogen linked to lung cancer and damage to the respiratory system when inhaled. It's also found in low levels in drinking water, and the researchers suspect exposure through drinking water and heavy use of 10 of the products they tested may lead to too much exposure.