We get it: Clean skin care can be confusing. And one of the most common questions any beauty expert gets is this: "What ingredients should I avoid?" It's a question that pops up so much because there's little to no regulation in the personal care industry, and thus consumers are left to figure it out for themselves. Thankfully, in the last several years, retailers and brands have stepped up: Many now have long "no" lists (or ingredients you won't find in their products) as well as just being generally more transparent as a whole. The industry is not perfect, but it's come a long way.
That being said, there are some things we generally advise you to avoid in your personal care products, as research has shown them to be questionable at best. They're commonly referred to as the "dirty dozen." If you stick to clean and natural products, you likely won't find these—but if you dabble in more traditional products, keep an eye out for these on the ingredient list:
Coal tar dyes
This pigment gives beauty products—from mascara and powdered shadow to hair dye—an inky black hue and is a byproduct of burning coal. The EWG ranks it as a 7 to 10, as studies have indicated it as an irritant and potential human carcinogen1. The use of the ingredient has been banned by the E.U., and there have been some regulations placed on its use by the FDA2 in the U.S., but not near enough according to many clean beauty experts. "While several variants of coal-tar-derived colorants have been prohibited for use over the years [as well as restrictions on concentration as well as mandatory labeling], broadly coal-tar-derived colorants are used in the industry still," says cosmetic chemist Yashi Shrestha, research scientist at the clean beauty retailer NakedPoppy.
The compound diethonolamine is used in a variety of products as a pH balancer (when you formulate beauty products with a variety of ingredients, the final pH might be too acidic, and this is added to make the final pH more alkaline). It's also the reason washes and soaps are sudsy. The EWG ranks the ingredient as a 7 to 10, as it is a known irritant to skin3 in a variety of human and animal studies, as well as a potential endocrine disrupter4. Not only that, but there's an environmental concern, as they can bioaccumulate. "Bioaccumulation in the environment is a concern that sometimes people don't think about, but we really should, just because you wash the soap off your body doesn't mean it stops there: It goes down the drain and can accumulate in our natural resources," says environmental expert Lindsay Coulter, who acts as the senior public engagement specialist at the Canadian environmental advocacy group David Suzuki Foundation. Currently, it is banned in the E.U.—however, the FDA does not deem it necessary to restrict its use. Along with DEA, look for its two other counterparts: MEA (monoethanolamine) and TEA (triethanolamine).
DBP is an oily substance used as a common fragrance ingredient, plasticizer (an additive that makes a formula more flexible or fluid), and solvent (a chemical that helps dissolve other actives). Though it is currently banned in the E.U., California has flagged it as hazardous material on Proposition 65 due to its potential to disrupt reproductive health.
Used to keep products stable, this class of ingredients is tricky. Few products are going to outright say they contain formaldehyde, yet several preservatives release5 the irritant over time, with temperature variations, or when it comes into contact with other actives. According to the EWG, a few of the most common are DMDM hydantoin, Imidazolidinyl urea, Diazolidinyl urea, Quaternium-15, Bronopol (2-bromo-2-nitropropane-1,3-diol), 5-Bromo-5-nitro-1,3-dioxane, Hydroxymethylglycinate. Formaldehyde is an issue for several reasons: First, we come into contact with the probable carcinogen6 often from various sources, from pollution to secondhand smoke—so we should limit our exposure when possible. But it's an issue for more day-to-day reasons, too: Research shows that even trace amounts of formaldehyde are enough to trigger dermatitis in humans7.
An older survey found that a releaser was found in one-fourth of all beauty products8; there is no more up-to-date version of this study to assess the current cosmetics industry. The E.U. has put restrictions on how much formaldehyde can be found in a product (less than 0.2%); while the FDA does not regulate this, the industry regulatory committee Cosmetic Ingredient Review does put involuntary guidelines to follow similar standards in the U.S.—however, we don't currently have the data to know how well brands follow this.
Phthalates and parabens
Two big clean beauty buzzwords you've likely heard if you follow the space: Phthalates and parabens are ubiquitous in the beauty industry, used in body care and skin care and makeup. "Banned by the European Union in 2003, phthalates and parabens are a group of chemicals commonly used as preservatives in cosmetics and pharmaceuticals," functional medicine doctor Frank Lipman, M.D., tells mbg. "[However] Both have been shown to be carcinogenic." Their overuse is much of the reason they are cause for concern, as they are absorbed dermally and have been shown to build up in the body with regular use9 in a variety of human studies. However, by limiting your exposure, those same studies show they are fairly easily flushed out of the body.
According to clean beauty experts the major problem with fragrances is transparency. Fragrances are considered a trade secret, and therefore brands do not have to disclose what actually went into the product—they can just put "fragrance" on the ingredient label. One older study found that there are, on average, 14 undisclosed ingredients in every product that has "fragrance" listed.
Clean retailers in the past few years have advocated for more transparency in their brand's fragrances. For example at clean beauty retailer Credo, the brands must at least disclose where the fragrance is sourced from (be it essential oils or safe synthetic fragrances), and many of their brands go as far as to list every single ingredient in their fragrance.
However, another element to keep in mind is sensitivity. Many people are sensitive to fragrances—natural or otherwise—and avoid them in products for personal reasons. This is why many derms will advise you to look for "fragrance-free" products if you have easily irritated skin or conditions like eczema.
BHA and BHT
BHA (or butylated hydroxyanisole, not to be confused with beta-hydroxy acids) and BHT (butylated hydroxytoluene) are closely related synthetic preservatives found in many skin care products like moisturizers and creamy makeup products like lipsticks. Currently, the watchdog and advocacy nonprofit the Environmental Working Group notes that BHAs, in particular, might be cause for concern, rating the ingredient a 5 or 6 on the scale of 1 to 10.
These are also called polyethylene glycols and are petroleum-based compounds that are widely used in cosmetics as thickeners, solvents, softeners, and moisture-carriers. The EWG rates polyethylene glycol low itself; however, clean beauty experts' primary concern with the ingredient class is the products it releases: ethylene oxide and 1,4 dioxane. These are heavy-duty sterilizers that the federal agency the Environmental Protection Agency notes10, "chronic, long-term exposure can cause irritation of the eyes, skin, nose, throat, and lungs, and damage to the nervous system" as well as evidence of being a human carcinogen.
Additionally, PEGs are often formulated to act as "penetration enhancers," meaning they allow other actives to reach farther into the epidermis but in doing so break apart your natural lipid barrier. "PEGs dissolve oil and grease. Thus, on the body, they take the protective oils off the skin and hair, making them more vulnerable to other toxins," notes Lipman.
Petrolatum, you'll likely see it as a petroleum, is a gelled mineral oil. It's used as a highly occlusive conditioning agent, meaning it helps seal in moisture. It is a byproduct of refining petroleum. Again, this is a tricky one: When it's fully refined, it's safe for external human use—with research showing no health concerns. However, it's not regulated by the FDA in the U.S., so it's possible that the petroleum that ends up in various beauty products is contaminated. The primary contaminant is polycyclic aromatic hydrocarbons (PAHs), which has been shown in human studies to be a carcinogen11. If you purchase a petroleum product, ensure that it has been vetted and verified as fully refined—even if the FDA does not require brands to do so, many will.
Otherwise known as silicones, these are often found in skin and hair care products—however, they get the lion's share of attention in the hair care space. They are used as softening and smoothing agents, providing a thin film over skin or hair that gives off the appearance of healthy, vibrant strands or complexion. The problem with this ingredient class is twofold: The first is specific silicones (D4 and D5) are shown to be potentially hazardous for human health and can also bioaccumulate in our water supply12.
The second is far less insidious, yet worth noting: Because silicone;s job is to create a film over hair and skin, it can be difficult to remove and causes buildup overtime. This is especially true of dimethicone, which is commonly found in hair care. The ingredient coats the strand but does not simply wash off with a shampoo—so with long-term, repeated use, you create a cycle of damage in the hair.
Sodium laureth sulfate
Sulfates are foaming and cleaning agents in soaps, detergents, and shampoos—and are met with ire in the clean beauty industry. We should note: Many people think sulfates are classed as carcinogenic, but they are, in fact, not—they are also allowed in the E.U. However, it's suggested to avoid the ingredient class as it is irritating to skin, eyes, and hair—stripping off all your natural oils. This has been shown to be very problematic for sensitive and inflamed skin, as it can trigger dermatitis13. And lately, significant research has shown sulfates are highly disruptive to your skin microbiome, which can have a cascading inflammatory effect on the body: Essentially, recent studies suggest that when your skin barrier is compromised, it not only causes external inflammation, but it causes internal inflammation as well. One study found that people with a poor skin barrier had more proinflammatory cytokines in the bloodstream than those who had healthy skin barrier.
This ingredient has had some of the most robust studies done on it in the last few years, and the research is showing more and more that its use in personal care and hygiene products should be restricted14. In fact, the EWG now rates it at a 7 depending on usage. Even though the FDA banned its use15 in antibacterial hand soaps in 2017, the agent is commonly found in toothpastes, dishwashing soaps, and other cleaning products. "This is a synthetic antibacterial ingredient that has been compared to nothing less than Agent Orange. The Environmental Protection Agency registers it as a pesticide, dangerous to any living organism. It is also classified as a chlorophenol, which means a cancer-causing chemical class. Triclosan disrupts hormones, can affect sexual function and fertility, and may be linked to birth defects," says Lipman.
Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and Allure.com. In her current role, she covers all the latest trends in the clean and natural beauty space, as well as lifestyle topics, such as travel. She received her journalism degree from Marquette University, graduating first in the department. She lives in Brooklyn, New York.