Ingredient Glossary

A byproduct of ethoxylation, listed as a probable human carcinogen. Not an ingredient — it's a contaminant.

Commonly found in: Products containing PEGs, SLES, or polysorbates

Used in conventional deodorants to block sweat. Controversial link to breast cancer and Alzheimer's; absorbed through the skin.

Commonly found in: Antiperspirants, some deodorants

Synthetic antioxidants used as preservatives. BHA is a possible human carcinogen; both disrupt endocrine function.

Commonly found in: Moisturizers, lip products, diaper creams, food packaging

Derived from petroleum, many are carcinogenic or contaminated with heavy metals.

Commonly found in: Hair dye, cosmetics, shampoos

Can react with other ingredients to form nitrosamines, known carcinogens. Irritating to skin and eyes.

Commonly found in: Shampoos, conditioners, lotions, soaps, sunscreens

Known human carcinogen. Releasers slowly emit formaldehyde into products over time.

Commonly found in: Nail polish, hair straightening treatments, shampoos, baby wash

A catch-all term hiding hundreds of undisclosed chemicals including phthalates, allergens, and carcinogens.

Commonly found in: Almost everything — body wash, lotions, cleaning products, candles, detergents

Skin-lightening agent linked to a skin condition called ochronosis with long-term use. Potential carcinogen.

Commonly found in: Skin lightening creams, some serums

Chemical UV filter that disrupts thyroid hormones and is absorbed into the bloodstream rapidly.

Commonly found in: Chemical sunscreens, some moisturizers with SPF

Chemical sunscreen filter that disrupts hormones and absorbs through skin. Detected in blood after single use.

Commonly found in: Chemical sunscreens, lip balms with SPF

Synthetic preservatives that mimic estrogen and can disrupt hormones. Linked to breast cancer tissue in studies.

Commonly found in: Lotions, shampoos, conditioners, makeup, deodorants

Derived from crude oil; can be contaminated with PAHs (polycyclic aromatic hydrocarbons), probable carcinogens. Clogs pores.

Commonly found in: Lip balm, moisturizers, hair products, baby oil

Plasticizers that disrupt hormones, impair reproductive health, and are especially harmful during pregnancy.

Commonly found in: Nail polish, hair sprays, synthetic fragrances, plastic packaging

Often contaminated with 1,4-dioxane and ethylene oxide, both carcinogens. Also enhances absorption of other chemicals.

Commonly found in: Creams, sunscreens, shampoos, toothpastes

May speed the development of skin tumors and lesions when used on sun-exposed skin.

Commonly found in: Sunscreens, anti-aging creams, lip balms

Harsh surfactants that strip skin and disrupt the moisture barrier. SLES is often contaminated with 1,4-dioxane, a probable carcinogen.

Commonly found in: Shampoos, body wash, toothpaste, face wash, dish soap

Persistent environmental pollutants that accumulate in body fat and breast milk. Weakly estrogenic.

Commonly found in: Synthetic fragrances, laundry detergents, fabric softeners

Cosmetic-grade talc is often contaminated with asbestos, a known carcinogen. Look for tested or certified talc-free products.

Commonly found in: Loose powders, dry shampoo, baby powder, eyeshadow

Nonstick coating linked to cancer, thyroid disease, and immune system disruption. Releases toxic fumes when overheated.

Commonly found in: Nonstick cookware, some makeup (mascara, foundation)

Antibacterial chemical that disrupts thyroid hormones and contributes to antibiotic resistance.

Commonly found in: Antibacterial soaps, some toothpastes, deodorants

Drying and can damage the skin barrier with regular use. Occasional use is generally fine.

Commonly found in: Toners, serums, hairspray, hand sanitizers

UV-blocking compound found in some lip products and nail polish. Possible carcinogen and hormone disruptor.

Commonly found in: Lip balms, nail polish, sunscreens

Generally safe but can erode tooth enamel in oral products and irritate sensitized skin at high doses.

Commonly found in: Toners, vitamin C products, cleaning products, oral rinses

Usually safe in small amounts, but can be irritating to sensitive skin and may enhance penetration of other chemicals.

Commonly found in: Moisturizers, serums, deodorants, hair products

Preservatives that are among the most common causes of contact allergic dermatitis.

Commonly found in: Shampoos, conditioners, wipes, some 'natural' cleaning products

Generally well-tolerated, but concentrations above 10% can cause flushing or irritation in some people.

Commonly found in: Serums, toners, moisturizers

A preservative considered safer than parabens, but may irritate skin and eyes in some individuals at higher concentrations.

Commonly found in: Lotions, serums, baby products, some 'natural' cosmetics

Effective anti-aging ingredient but increases sun sensitivity. Avoid during pregnancy. Use at night with SPF in the morning.

Commonly found in: Anti-aging serums, eye creams, moisturizers

Not harmful to health, but coat the skin and hair, potentially blocking absorption of beneficial ingredients. Environmental concern.

Commonly found in: Primers, conditioners, moisturizers, serums

Antimicrobial preservative that can cause contact dermatitis. Also a concern for antibiotic resistance.

Commonly found in: Eye drops, some hand sanitizers, disinfectant wipes

Derived from seaweed; used as thickener. Some animal studies link it to GI inflammation, though evidence in humans is limited.

Commonly found in: Plant-based milks, some skincare products, toothpastes

Naturally derived but potent — can cause allergic reactions, photosensitivity (citrus oils), or hormone disruption (lavender, tea tree) in some.

Commonly found in: Natural skincare, aromatherapy, 'clean' cleaning products

Preservative that may disrupt thyroid function. The EU restricts it in products for 3-and-under.

Commonly found in: Wipes, some moisturizers, some shampoos

Natural fragrance compounds that oxidize to allergens when exposed to air. Common skin sensitizers.

Commonly found in: Natural fragrances, essential oil blends, some 'clean' products

Possible carcinogen found as a contaminant in some polystyrene packaging. Trace amounts may migrate into products.

Commonly found in: Products in polystyrene containers

Gentler alternatives to SLS, but still surfactants that can strip moisture in sensitive individuals.

Commonly found in: Shampoos, body wash, toothpaste

Petroleum-derived dyes that may contain trace heavy metals. Some are restricted in the EU.

Commonly found in: Cosmetics, nail polish, hair color, some food products

Safe in sunscreens on skin, but inhaled titanium dioxide (in spray sunscreens or powders) is a possible carcinogen.

Commonly found in: Spray sunscreens, loose powders, paint

Nano-sized particles in sunscreens may penetrate skin more than non-nano; research is ongoing. Non-nano zinc oxide is considered safe.

Commonly found in: Mineral sunscreens