Some skin and hair care ingredients get a bum rap, with critics raising the alarm—claiming certain compounds are absorbed through the skin and into the body where they contribute to disease. But how valid are the allegations? YouBeauty takes a look at some of the most talked-about culprits.
What are they?
Parabens are compounds that are used in makeup, lotions and shampoo, as well as in food and medicine. They’re preservatives that help prevent bacterial and fungal growth. The most common ones you’ll see listed on cosmetic labels are methylparaben, ethylparaben, propylparaben and butylparaben.
According to the Food and Drug Administration, the most common parabens are safe at concentrations up to 25 percent. That’s much higher than the levels found in many products, which typically have concentrations of less than one percent. (It’s worth noting that in 2010, the European Union lowered the legally allowable levels of butylparaben and propylparaben in cosmetic products to 0.19 percent.)
Should I be worried?
Once inside the body, parabens can mimic estrogen, the hormone that controls most female reproductive functions. Like all hormones, estrogen sends biological signals by attaching to specific receptors throughout the body. The parabens act as a hormone disruptor—attaching themselves to the same receptors and interfering with the body’s natural communication system.
High levels of estrogen may stimulate the growth of some types of breast cancer, and the concern is that estrogen-like hormone disruptors may do the same. But so far, it appears that it takes a higher concentration of parabens to have the same effect as a smaller amount of naturally-produced estrogen.
In 2004, a team led by Philippa Darbre, Ph.D., from the U.K.’s University of Reading, published the first study showing evidence of parabens in breast tumors. Since then, additional research has found evidence of parabens in breast milk and non-cancerous breast tissue. But there is no proven link that indicates parabens cause breast cancer, explains Darbre.
Another unknown: how parabens affect the body when other hormone disruptors, such as BPA (bisphenol A), or estrogen found in birth control or hormone replacement therapy are taken into account. Individually, these compounds may be harmless, but their cumulative effect on the body is unknown.
According to Darbre, even if parabens do contribute to breast cancer (which hasn’t been proven conclusively), it may be difficult to tease out that link amongst all the other potential environmental and genetic influences. Since we might never know for sure, says Darbre, she advises avoiding paraben-containing products. To suss them out, check for any ingredient with “paraben” as its root on the ingredient list. Those listed at the top of the list generally appear in highest concentrations, while those listed near the end have the lowest amounts. And for people who don’t want to quit them altogether, the good news is they don’t appear to bioaccumulate, meaning the body flushes them out relatively quickly.
What are they?
Phthalates are plasticizers that make plastics less brittle. Over a dozen different phthalates can be found in everyday items from plastic toys to food packaging, as a cosmetic ingredient to keep nail polish from chipping, hair products from being too stiff, or as a solvent in fragrances.
Should I be worried?
Phthalates and the molecules produced as they break down in the body have been found in human milk, urine, saliva, blood serum and amniotic fluid—although it’s not clear if they got there through skin exposure.
And, just like parabens, certain phthalates are known hormone disruptors. But rather than mimicking estrogen, phthalates interfere with testosterone production—meaning the body produces far less of this important male hormone than what’s needed for normal development, explains Russ Hauser M.D., M.P.H, Sc.D., an environmental health scientist at Harvard University.
There is limited research on whether phthalates have a direct risk for women, although a 2003 North Carolina State University study showed that di(2-ethylhexyl) phthalate (DEHP) disrupted estrogen production in female rats. For now, the biggest concern is whether a woman who is pregnant or nursing can pass phthalates onto a developing fetus or infant.
Studies on rats have also shown that certain phthalates cause abnormalities in male development, including undescended testicles and a shortness of the distance between the anus and the genitals. However, the rats in these experiments were exposed to levels of phthalates far higher than what humans typically experience.
The good news is that the phthalate most commonly found in cosmetics, diethyl phthalate (DEP) doesn’t appear to have a strong anti-testosterone effect in rats, which may mean it is also safe for humans. But riskier phthalates do show up in some cosmetic formulations. And, as with parabens, the cumulative phthalate load is a concern.
“We know people are exposed to hundreds of chemicals,” says Hauser. Even if the level of one phthalate is low, he adds, the combination of that phthalate with other phthalates and other chemicals is unknown.
Just like parabens, most phthalates are eliminated by the body within a day or so. To check for them in cosmetics, look for any chemical name that includes “phthalate” on the ingredients list. Also be aware that phthalates are common in fragrances, and the F.D.A. doesn’t require companies to list individual ingredients if a scent is proprietary.
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