The concern raised about these widely used synthetic preservatives stems from research showing that parabens can mimic the hormone estrogen and a broadly criticized 2004 study that suggested a potential link between parabens and breast cancer. But what if parabens are not as dangerous as feared? And what if the substitutes being used in countless “paraben-free” products can have major side effects? Could it be that the focus on parabens has been misplaced?
That’s the stance of many scientists — including Philippa Darbre, professor emeritus in the School of Biological Sciences at the University of Reading in Great Britain, who led the controversial 2004 study that sparked the worry about parabens and breast cancer. And it’s making some of us who follow the industry (including myself, once open to the concept of “clean” beauty) start digging into the science that has spread fear of parabens and other synthetic ingredients.
But first, some background: Parabens were introduced in the 1920s and are found in personal care items, food products and pharmaceuticals such as antacids, cough suppressants and antidepressants. They became the preservatives of choice because they are broadly antimicrobial and inexpensive and rarely prompt an allergic response. Of the 21 parabens, the four most commonly found in cosmetic and skin care products are methylparaben, propylparaben, butylparaben and ethylparaben.
These concentrations are higher than those typically used in cosmetic formulations, according to Lalita Iyer, a New York City-based cosmetic chemist who has formulated personal care products for both beauty conglomerates and indie brands. “Parabens are one of the most effective broad-spectrum preservatives out there,” Iyer said. “The beauty of parabens is that you can really use them at a low percentage.”
But doubts about the safety of parabens were raised in the late 1990s, when research led by British molecular endocrinologist Edwin Routledge indicated they could have an estrogenic effect. Those results prompted Darbre’s 2004 paper, a small study that found parabens in the tissue of breast tumors and sparked concerns that there could be an association between parabens and breast cancer. While much of the research into the hormonal effects of parabens that followed was conflicting, none of it confirmed a connection between parabens and breast cancer.
According to “Parabens Toxicology,” a 2019 review of the literature led by surgical dermatologist Anthony Fransway, no study of parabens has concluded that they contribute to hormone disruption, breast cancer or skin cancer in humans. “Until such time as convincing data are published and verified, claims that parabens have any role in these controversial and important health problems are premature,” the researchers wrote.
But that didn’t settle the matter. While research was ongoing, concern about parabens had taken hold in the public, and “paraben-free” products started appearing on drugstore shelves and beauty counters. Experts warn, however, that these formulations are potentially more harmful than their counterparts because the preservatives used in place of the parabens are less studied and more likely to cause an allergic response or allow product contamination.
“The issue is that when people freaked out about parabens, we started using more preservatives, which are way more allergenic,” said Walter Liszewski, an assistant professor of dermatology specializing in allergic contact dermatitis at Northwestern University in Chicago. “For example, my Head & Shoulders shampoo says ‘paraben-free’ but uses methylisothiazolinone (MIT) in place of parabens, which is way nastier.” Methylisothiazolinone is a known contact allergen.
Iyer, the cosmetic chemist, added that natural preservatives typically do not extend the shelf life of a product more than six months, compared with two years for parabens, and that natural preservatives kill a much narrower spectrum of microbes. “This is extremely problematic,” she said.
According to the FDA’s “Cosmetics Recalls and Alerts” page, several “clean” companies have voluntarily recalled products in the past two years because of the presence of mold, yeast and bacteria. This included multi-level-marketing company Beautycounter, which voluntarily recalled Beautycounter Brilliant Brow Tinted Brow Gel because testing found a species of mold Penicillium.
Esther Oluwaseun, a Santa Ana, Calif.-based research and development formulation chemist, said that most of the recalled product cases listed on the FDA’s site could have been avoided had the brands used broad-spectrum preservatives like parabens. “But because parabens have been demonized, formulators are forced to use less effective preservative systems.”
Darbre’s 2004 study, “Concentrations of parabens in human breast tumours,” has been broadly discredited. Critics started raising concerns immediately after its publication, citing the study’s small sample size (20 tumors), its failure to look at control samples of normal breast tissue, its inability to determine the source of the parabens and possible contamination of samples used in the research.
Later that year, Darbre published a response in the Journal of Applied Toxicology stating, “Nowhere in the manuscript was any claim made that the presence of parabens had caused the breast cancer.” But in the public mind, the connection had been made, though scientists and organizations have continued to point out the research’s flaws.
The American Cancer Society agrees with the criticism: “The study did not show that parabens caused or contributed to breast cancer development in these cases — it only showed that they were there,” it says on a Web page about parabens. The National Cancer Institute also noted that there is no evidence parabens cause breast cancer and included a footnote to a 2019 report by the industry-funded Cosmetic Ingredient Review’s expert panel, which concluded that 20 of the 21 parabens in the report are safe in cosmetics as long as the total in a product is less than 0.8 percent.
Despite the strong critiques, Darbre’s study has been cited close to 1,000 times since publication. Timothy Caulfield, the Canada research chair in health law and policy at the University of Alberta, said it’s not unusual for what he calls “zombie papers” to live on. “This is a big problem — bad studies are polluting the academic literature and, sometimes, meta-analysis.”
Caulfield said there are other forces at work that are contributing to the public’s wariness of parabens, however, pointing to some beauty companies that he says spread “chemophobia” (the irrational fear of chemicals). “I don’t know a universe where chemicals don’t exist,” he said, “but that’s the narrative that brands like Goop and Honest Company like to sell, and unfortunately, it’s extremely effective.” Goop and Honest Company declined to comment.
Iyer also cited the influence of retailers such as Sephora that promote paraben-free products. “Brands want that ’Clean at Sephora’ label on their products,” she said, “so they refuse to use parabens.” A representative from Sephora said the company’s Clean at Sephora criteria “reflect the latest data and research.”
But Iyer also has concerns about the way research about parabens is being disseminated to the public. “I think a lot of the push away from parabens stems from organizations like the Environmental Working Group (EWG) spreading misinformation and cherry-picking data to meet their agenda.”
The activist organization’s science, tactics and publications, including its annual “Dirty Dozen” list of produce most likely to be contaminated by pesticides, have been questioned by experts.
Iyer pointed to the EWG’s parabens overview page, saying that the organization had chosen “outdated studies to meet their narrative” and left out context. For example, the page cites a study of rats exposed to butylparaben during development, which found harm to the animals’ reproductive systems. But, she said, the rats were orally fed high amounts of parabens “which is quite different than topical application on humans. It’s fearmongering.”
When asked about these examples, Carla Burns, the EWG’s senior director of cosmetic science, said the parabens article was written in 2019. “We have more recent information,” she said, “and the continuing, evolving scientific space is listed on our Skin Deep database under each of the applicable paraben ingredient pages.”
Evolving science does not seem to have affected the public’s mistrust of parabens, however. That concerns Darbre, author of the 2004 study, who has continued her research into estrogenic chemicals. She now says many hundreds of such chemicals “may add together at low concentrations to make cells grow up to their maximal rate.” Therefore, she said, “hounding” one set of chemicals, such as parabens, is not useful.
“It would be wonderful if a single chemical could be identified as a sole problem and then replaced by something ‘safe,’ but this is unlikely to happen,” Darbre said. “What often happens now is that one chemical with ‘bad press’ is replaced by a new chemical with less data.”
She cited the reduction of bisphenol A (BPA), a chemical heavily used in plastics until 2008. When products are sold as “BPA-free,” she said, it “lures everyone into thinking that the new products are ‘safer’ when all that has happened is that other bisphenols have replaced bisphenol A.”
And as for parabens, which are being stripped from products partly based on her research? “They are cheap and effective as preservatives,” she said, “and the only alternative to removing preservatives is for the shelf life to be reduced dramatically.”
Janna Mandell is a San Francisco-based journalist covering the beauty and wellness industries.