The Dirty Dozen Chemicals in Cosmetics

Beauty is only skin deep, but the products we use to attain it contain chemicals that may penetrate far deeper. The average adult uses nine personal care products a day, with roughly 120 chemicals spread among them, many of which are incompletely tested for toxicity.

Below we've listed 12 chemicals that are best avoided. A single exposure to any of them is unlikely to cause harm, but daily exposure over a lifetime may add up. When shopping, be prepared to spend some time reading labels; even brands that advertise themselves as "natural" or "botanical" have been known to include some of these (see our Smart Shopper's Dirty Dozen Ingredients card).

1. Antibacterials
Overuse of antibacterials can prevent them from effectively fighting disease-causing germs like E. coli and Salmonella enterica. Triclosan, widely used in soaps, toothpastes and deodorants, has been detected in breast milk, and one recent study found that it interferes with testosterone activity in cells. Numerous studies have found that washing with regular soap and warm water is just as effective at killing germs.

2. Coal Tar
Coal tar is a known human carcinogen used as an active ingredient in dandruff shampoos and anti-itch creams. Coal-tar-based dyes such as FD&C Blue 1, used in toothpastes, and FD&C Green 3, used in mouthwash, have been found to be carcinogenic in animal studies when injected under skin.

3. Diethanolamine (DEA)
DEA is a possible hormone disruptor, has shown limited evidence of carcinogenicity and depletes the body of choline needed for fetal brain development. DEA can also show up as a contaminant in products containing related chemicals, such as cocamide DEA.

4. 1,4-Dioxane
1,4-Dioxane is a known animal carcinogen and a possible human carcinogen that can appear as a contaminant in products containing sodium laureth sulfate and ingredients that include the terms "PEG," "-xynol," "ceteareth," "oleth" and most other ethoxylated "eth" ingredients. The FDA monitors products for the contaminant but has not yet recommended an exposure limit. Manufacturers can remove dioxane through a process called vacuum stripping, but a small amount usually remains. A 2007 survey by the Campaign for Safe Cosmetics found that most children's bath products contain 10 parts per million or less, but an earlier 2001 survey by the FDA found levels in excess of 85 parts per million.