How Good Housekeeping surveyed 900-plus readers to find out which synthetic ingredients topped their list of concerns. Then we asked experts to weigh in on which are simply annoying (for example, merely skin-irritating) and which may lead to more serious trouble (endocrine problems, or even cancer). Unfortunately, because research in humans tends to be scant, the risks in many cases are not well-known. But here is what we do know, and what you can do about five of the ingredients that worry you most.
Listed on labels as methylparaben, benzylparaben, or other ingredients ending with the same word, these effective preservatives are used in cosmetics from lotions to lipsticks.
Since many parabens appear to mimic the activity of estrogen in the body, there's concern that they may affect the endocrine system (hence the term "endocrine disruptor") and lead to decreased sperm counts in men and even breast cancer in women. A much-debated 2004 study found parabens in a small sample of 20 cancerous breast tumors. A follow-up study this year yielded similar results: Parabens were found in the breast tissue of 40 women who'd undergone mastectomies. However, "neither study proves parabens caused the cancer," explains breast cancer researcher and retired surgeon Susan Love, M.D. "The published data on cancer risk from parabens is either on cells grown in petri dishes or on lab rats, and unfortunately, you cannot extrapolate from those to women. We need more research in women to actually figure this out." One study has shown that even a very strong paraben is only a weak endocrine disruptor at worst, 10,000 to 100,000 times less active than estrogen itself. And most products that use parabens contain only low concentrations, from .01% to .3%. The FDA maintains, based on currently available data, that parabens are safe for use in cosmetics, but if you're still concerned, paraben-free beauty options are abundant - check labels.
Related: 5 All-Time Best Haircuts
2. SYNTHETIC COLORS AND DYES
Colorants are "the most highly regulated cosmetic ingredients in the U.S.," says cosmetic chemist Perry Romanowski.
In 1938, to protect consumers, Congress gave the FDA authority to regulate color additives. Due in part to questions about carcinogenicity, the agency has banned a number of dyes and has specified where certain ones may be used - for example, only food-grade dyes can be used in products applied around the eyes, Romanowski says. One exception to the ban: coal-tar dyes. These dyes can be used in darker hair-coloring products, provided they carry a warning about possible skin sensitivity and against dyeing eyelashes or eyebrows (which may cause blindness). "Coal-tar dye ingredients [listed on labels as, for example, 4-methoxy-m-phenylenediamine (4-MMPD)] are infrequently used," says Romanowski. In addition, the FDA notes that surveys show the industry has phased them out (go to fda.gov for a list of hair dyes shown to cause cancer in animal studies).
This large class of chemicals derived from fossil fuels includes gasoline, coal, tar, and the common beauty-product ingredient petrolatum (a.k.a. petroleum jelly).
An inexpensive, effective sealant that traps moisture, petrolatum is well tolerated by people who have irritable skin and is a choice dry-skin remedy of dermatologists, says Valori Treloar, M.D., of Newton, MA. While petrolatum may contain trace impurities of a class of chemicals called polycyclic aromatic hydrocarbons (PAHs) - probable carcinogens - manufacturers can eliminate the contaminants via a chemical process, says Nneka Leiba, a senior analyst with the Environmental Working Group. "The petrolatum grade used in cosmetics undergoes strict purification," says Romanowski. Still, a 2001 study found tiny quantities of a few PAHs in multiple petroleum jelly brands. The risk, if any, is contested, but if you're concerned, minimize exposure to PAHs by choosing cosmetics without petrolatum, petroleum jelly, or mineral oil on their labels.
Related: 30 Best Beauty Buys For $10 Or Less!
These multipurpose chemicals are used in cosmetics to reduce brittleness in nail polish, make fragrances last longer, and more. Two common ones: DBP (di-n-butyl phthalate) and DEHP (di [2-ethylhexyl] phthalate).
In studies on lab rats, certain phthalates have been shown to have "an anti-testosterone effect linked to testicular changes, liver injuries, and cancer," says Dr. Treloar. In addition, male rats exposed to phthalates in utero have been born with reproductive-system defects. To protect consumers, the European Union has banned DBP, DEHP, and a third phthalate, BBP, in cosmetics; closer to home, the Environmental Protection Agency (EPA) has placed DBP and DEHP on a list of chemicals that may present a hazard to humans. (In the U.S., DBP, DEHP, and BBP have been banned from children's toys in amounts greater than .1%.) Moreover, a recent study of 319 mother-and-child pairs from Columbia University Mailman School of Public Health showed a link between higher phthalate exposure in utero and slower development, including motor delays and increased behavioral problems. The good news: If you're concerned about phthalates in cosmetics (one of many sources of these chemicals) and/or wish to avoid them during pregnancy, manufacturers have reformulated products, particularly nail polish, to be DBP-free.
Related: 70+ Bedroom Decorating Ideas
5. SYNTHETIC FRAGRANCES
Formulas for scents, synthetic and natural, are closely guarded trade secrets, whether in a perfume or the fragrance of your favorite lotion.
Manufacturers aren't required to disclose ingredients (you'll simply see "fragrance" on the ingredients list). So while synthetic fragrances and fragranced cosmetics may contain phthalates, you won't be able to discern which ones. Nor will you be able to tell if a scent contains galaxolide or tonalide, synthetic musks thought to be endocrine disruptors. Doctors' main concern regarding scents is that they can cause an allergic reaction or dermatitis in sensitive skin - and that goes for natural fragrances, too. If you're sensitive to fragranced products or want to avoid added phthalates (some of these chemicals may sneak in, for example, through the supply chain or in manufacturing), seek out the plentiful "fragrance-free" options in stores.
More from Good Housekeeping: