Shop for cosmetics with natural ingredients, and stay away from anything that lists “fragrance” or “parfum” as an ingredient.

The effects of cosmetic chemicals may be more than skin deep.

RODALE NEWSROOM, EMMAUS, PA—Chemicals associated with cancer and hormone disruption turned up in the blood and urine of every teenage girl tested in a recent study by the Environmental Working Group (EWG). The September report found that the teens tested had an average of 13 hormone-altering chemicals in their bodies. The chemicals in question are commonly found in makeup and body-care products; a questionnaire administered on the day of the blood tests revealed that the girls used 17 personal-care products that included more than 174 chemical ingredients.

THE DETAILS: Researchers tested the blood and urine of 20 teenage girls, ages 14 to 19, looking for 25 chemicals often found in cosmetics. The teens involved in the study lived in different parts of the country and included white, black, Asian-American, and multiethnic girls. Tests detected 16 chemicals from 4 chemical families in either the blood or urine of the girls, including:

Phthalates, which have been linked with reproductive and developmental problems and an increased risk for asthma and allergies. They are often in products that list “fragrance” as an ingredient.

Triclosan, the bacteria-killing ingredient in antibacterial liquid soaps. Research suggests it can promote antibiotic resistance, which means some infections could start outsmarting our medicine. When it gets into the waste stream, triclosan can have a toxic effect on aquatic life. It’s also been linked to thyroid problems in people.

Parabens, possible endocrine disrupters and carcinogens; may impair fertility.

Synthetic musks, manmade chemicals used as fragrances and perfumes in many cosmetics, shampoos, soaps, and deodorants. Some have been linked to cancer in lab animals. “Musk” also refers to an odor some animals give off, but synthetic musks are made in labs.