chemical information


Chemical Class:


Found in these people:

Jessica Assaf, Rizza Alcaria, Anonymous Teen 9, Emma Spencer, Natalie Klapper, Anonymous Teen 11, Sarah Oswald, Jenny Gilbertson

Found in these locations:

San Rafael, CA; Manteca, CA; Washington, DC; Winchester, MA; San Francisco, CA; Los Angeles, CA; Palm Beach Gardens, FL; Novato, CA


Parabens are extremely common synthetic preservatives used in cosmetics and personal care products, and also in some foods, beverages, and pharmaceuticals. Parabens are absorbed rapidly through intact skin (CIR 2006). Isopropylparaben, a branched form of propylparaben, is not in common use, and few studies describe the toxicological properties of this chemical.

Isopropylparaben is known to trigger irritation and allergic reactions in the skin, especially damaged or broken skin (Schamberg 1967; Nagel 1977; CIR 2006). Generally parabens are thought to mimic estrogen (Routledge 1998), causing concern that they may contribute to estrogen-stimulated breast cancers. In fact, research from 2002 found that doses of a similar compound, propylparaben (also called n-propylparaben), increased the growth and gene expression of estrogen-sensitive breast cancer cells, responses similar to those provoked by a potent form of estrogen known as estradiol (Byford 2002).

Animal studies on propylparaben suggest that isopropylparaben may have other hormone-disrupting effects as well. Exposing young rats to propylparaben in food led to reduced sperm and testosterone production in males (Oishi 2002). The exposure level that triggered this harm to the male reproductive system was the same as that thought to be acceptable for daily intake by the European Union and Japan (10 mg/kg body weight/day; Oishi 2002). Studies on fish species have revealed estrogenic (Inui 2003) and antiestrogenic (Mikula 2006) effects caused by exposure to propylparaben, indicating a potential for more complex hormone activity. Aquatic organisms can suffer reproductive harm resulting from exposure to hormone-disrupting chemicals present in treated wastewater discharged to lakes and streams. Research on related paraben compounds indicates the branched or iso- forms of these chemicals may be more estrogenic than the linear or n- forms (Darbre 2002).


Preservative widely used in cosmetics. Can trigger skin allergy and irritation, and may be linked to hormone disruption and breast cancer.

Isopropylparaben has been found in 8 of the 28 people tested in EWG/Commonweal studies.

Results for Isopropylparaben

in urine

Showing results from Dateline NBC Families, EWG Study #10, cosmetic chemicals in teens, Dateline NBC Families

EWG/Commonweal results

  • geometric mean: 0.398 ug/g creatinine in urine
  • found in 8 of 28 people in the group
ug/g creatinine in urine 20.7

Isopropylparaben results