20 Ingredients a Clean Cosmetic Chemist Would Avoid

When it comes to our beauty products, it might seem as though the list of ingredients to avoid is growing longer by the minute. But, that's not to say you should demonize every ingredient that's part of the conversation– truthfully, marketing has a lot to do with it. However, there's also new science coming out all the time, that offers more evidence-based information about what is and isn't good for your skin, which can help inform your decision about what to use. Then, of course, there are also personal differences because what may cause sensitivity for you might work well for someone else. Ultimately, this leaves the responsibility to the consumer to know what's good for them and what's not—and that's no easy task with all of the misinformation that's out there. To set the record straight, we consulted with three cosmetic chemists who share their expert insight into which skincare ingredients are best to avoid.

Which Chemicals Are Harmful for Skin?

Studies show that parabens and phthalates are harmful, endocrine-disrupting chemicals commonly found in beauty products but that's just beginning. Thanks to a slow-evolving industry, it's up to you to decide what ingredients you want to steer clear of. "Unfortunately, cosmetics and personal care products have little government oversight, which means many products, and the ingredients used in today's beauty products, are not well-regulated," Shrestha explains. "There is really no legal definition of clean or non-toxic," King adds. "Most of the standards are made up by retailers."

Koestline notes that carcinogenic ingredients like dibutyl phthalate (used in nail polish) and m-Phenylenediamine (used in hair color) were recently banned in California but are still allowed everywhere else. This is a great example of the inconsistencies in ingredient regulation—just because an ingredient may not be banned, does not mean that it's good for the skin.

Toxic Ingredients to Avoid

Formaldehyde: Despite decades of research that classifies formaldehyde as a known carcinogen, it’s still a fairly common ingredient in hair straightening products, nail polish, eyelash glue, and an array of other cosmetics. Thankfully, some retailers (including Whole Foods, CVS, and Target) are starting to ban products that contain formaldehyde from their shelves. 

But there’s a catch. “While formaldehyde has become a well-known toxic ingredient to avoid in beauty products, many don’t know about the lesser known ingredients that release formaldehyde which are formulated in cosmetics today,” says Shrestha. In other words, while it’s unlikely that you’ll see the word “formaldehyde” on an ingredient label, it might be hiding behind another name.

Formaldehyde releases: “Bronopol, DMDM hydantoin, diazolidinyl urea, imidazolidinyl urea, and quaternium-15 are cosmetic preservatives that slowly form formaldehyde,” says Shrestha. So steer clear if you can.

Synthetic fragrances: A heads-up: When an ingredient label simply says “fragrance” or “parfum,” it’s often an umbrella term for hundreds of chemicals that brands aren’t required to disclose. (That makes it a heck of a lot harder to discern what may cause a reaction.)

Phthalates: One such sneaky compound hiding under the “fragrance” umbrella? That would be phthalates, which are sometimes used to help perfume stick to skin, as well as eyelash adhesive and nail polish. That’s bad news because phthalates have been shown to be pretty significant endocrine disruptors—in some cases facilitating early puberty in girls and boys, and reduced sperm count in men. Oh, and did we mention they’re also harmful to the environment? The EWG reports that some retailers have started to ban phthalate-containing products from their shelves, but we still recommend a healthy dose of skepticism when it comes to added fragrance.

Polyethylene glycol (PEGs): On a similar note: Polyethylene glycol, “propylene glycol (PG) and butylene glycol (BG) could potentially be petroleum derived and irritating to the skin,” says Shrestha. These are chemical thickeners and can sometimes be found in cream-based products.

Siloxanes: Also known as cyclical silicones, these compounds are found in a variety of cosmetic and skincare products—but they’re not great for the environment, and have been linked with endocrine disruption as well. (Dimethicone, on the other hand, is considered safer when used sparingly.)

Triclosan: This antimicrobial ingredient (often found in hand sanitizers and antibacterial soap) has been linked to such a significant impact on the thyroid and reproductive hormones that it’s banned in several countries. The US has banned it from antiseptic soap, but it might still show up in deodorant, mouthwash, shaving cream, and toothpaste, says the EWG.

Ethanolamines: While these compounds (which are emulsifiers found in foundation, mascara, and skincare products) are technically classified as safe for cosmetic use by the EWG, they’re also shown to be allergens—something to keep in mind if you have sensitivities to certain ingredients. They might be listed as monoethanolamine (MEA), diethanolamine (DEA), or triethanolamine (TEA).

Oxybenzone: A potential endocrine disruptor, oxybenzone can be found in many skincare products that contain sunscreen, "including lotions, lip balms, cleansers, fragrance, and even baby products,” says Shrestha.

Octinoxate: This common sunscreen ingredient was thought originally to be harmful to coral reefs, and although that may have been recently proven false, it's still somewhat irritating to sensitive skin.

Homosalate: “This is another chemical that’s commonly used in sunscreens as a UV absorber,” says Shrestha. While regulations are starting to wisen up to octinoxate and oxybenzone, homosalate is still pretty commonly used.

Toluene: This chemical (which also goes by the name of Butylated Hydroxytoluene, or BHT), is a big no-no: It’s linked with brain toxicity and can be especially dangerous during pregnancy. While it’s banned in the EU and Southeast Asia (as well as by a few retailers in the US), you can still find it in nail polish, nail treatments, and hair dye.

Talc: While talcum powder (often used as a smoothing agent in mineral makeup) is generally safe, it also has the potential to be contaminated with asbestos, which is a known carcinogen and instigator of lung disease.

Per- and poly-fluoroalkyl substances (PFAs) and Perfluorochemicals (PFCs): Remember how we said that the term “fragrance” can potentially be hiding hundreds of chemicals? Well, PFAs are a class of thousands. “They’re fluorinated chemicals that have been found in sunscreens, hair products, and shaving creams,” says Shrestha. “They’re linked to serious health effects, including cancer, thyroid disease, and even reduced effectiveness of vaccines.”

If you commonly use waterproof mascara or eyeliner, take note: PFCs are big culprits here because they’re water repellents. 

Teflon: Teflon is one specific PFA worth calling out—it’s the brand name for Polytetrafluoroethylene (PTFE), and is sometimes added to cosmetics to improve the texture. But like other PFAs, it’s linked to hormone disruption and reproductive issues.

Resorcinol: “This common ingredient in hair color and bleaching products has been linked to skin irritation and immune system dysfunction,” says Shrestha. “In animal studies, resorcinol can disrupt normal thyroid function.”

Carbon black: The EWG has flagged this pigment (which is often found in mascara and eyeliner) because of its possible link to cancer with regard to inhalation (not topical application). For what it’s worth, the FDA has put some limits on the amounts used—but it’s still widely found in cosmetics at retailers everywhere.

Parabens: “Butyl, propyl, and ethyl parabens have been linked to hormone disruption,” notes Shrestha. These are preservatives that are found in a variety of cosmetics and are probably the most well-known ingredient to avoid due to a 2004 research paper that appeared to find traces of parabens in breast cancer tissue samples. According to EU and FDA regulations, parabens in their current form are officially considered safe to use, since cosmetic products only use a very small concentration of these ingredients in their formulas (up to around 0.4 percent, though measurements do differ for each paraben). It's important to note, however, that parabens may be irritating to some with sensitive skin.

Hydroquinone: This one may surprise you, but the safe use of the hyperpigmentation savior has long been debated, with some countries banning it for its potential carcinogenicity. "Hydroquinone is cytotoxic," explains King. "It kills the cells, thus great for skin brightening, but it has been banned."

This Is Not About Fear

Knowledge is power—and you can feel good about taking steps to better understand exactly what you’re putting on your body. "Consumers are becoming more conscious about the environmental impact of certain ingredients, and clean beauty is evolving to have more visibility into the supply chain and sourcing of ingredients," notes Shrestha. Think of this list as a jumping-off point for anyone curious about learning more about sketchy ingredients and clean beauty as whole. We recommend doing your own research on all of the ingredients above, then making a decision that feels right for you.

“Given the lack of regulations and federal oversight on what ingredients are allowed in beauty products, it’s important for consumers to seek out and demand products that are clean,” says Shrestha. “This not only drives innovation for brands creating better products, but also increases accountability so that consumers don’t have to spend time doing research on ingredients to ensure safety.” In other words, get comfortable calling brands on their BS—all in the name of a safer beauty industry for all.