The Impact of Junk Science on R&D: A Review of the 'Dirty Dozen'

By: David C. Steinberg, Steinberg & Associates

Posted: September 29, 2010, from the October 2010 issue of Cosmetics & Toiletries.

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The next ingredient on the list is cyclomethicone as well as ingredients ending in siloxane, e.g., cyclotetrasiloxane. The report states: Cyclomethicone and siloxanes are used in cosmetics to soften, smooth, and moisten. These compounds can, however, irritate the skin, eyes and lungs. They are also suspected of interfering with hormone function (endocrine disruption) and of liver toxicity. These chemicals are persistent. In other words, they don’t easily degrade and can remain in the environment long after they are rinsed down the shower drain. Environment Canada considers cyclotetrasiloxane and cyclopentasiloxane to be toxic to fish and other aquatic organisms.

Facts: Both the CIR and EU have reviewed the safety of cyclotetrasiloxane and cyclopentasiloxane and neither has found studies to indicate these materials cause eye irritation, skin irritation or irritation to the lungs. If the foundation has valid scientific studies to prove these charges, this author suggests the group submit them. Environment Canada has not yet completed its work on these materials and could restrict the use of cyclotetrasiloxane since it is suspected under the Canadian Environmental Protection Act to potentially be toxic to the environment.¹⁹ This is why using the generic term cyclomethicone in ingredient listings should be avoided.

In addition to these two ingredients, the INCI dictionary lists 30 other ingredients ending in siloxane that have been approved for cosmetic use. The FDA database shows the following numbers of formulations containing these materials: 1,506 with cyclomethicone; 76 with cyclotetrasiloxane; 3,004 with cyclopentasiloxane and 759 with cyclohexasiloxane. Again, some vendors have introduced replacement ingredients for these materials to allow “free from” claims, although such claims are self-destructive to the industry, as is evidenced by this column.

Sodium Laureth Sulfate

The foundation also cautions consumers to watch for sodium lauryl sulfate and other related ingredients that include the letters eth. According to the report, sodium laureth sulfate is used in cosmetics as a cleansing agent and also to make products bubble and foam. This and other “ethoxylated” ingredients (which usually have chemical names including the letters “eth”) may be contaminated with ethylene oxide and 1,4-dioxane. Both contaminants may cause cancer. Also, ethylene oxide may harm the nervous system and interfere with human development, and 1,4-dioxane is persistent. In other words, it doesn’t easily degrade and can remain in the environment long after it is rinsed down the shower drain.

Facts: The foundation has already condemned sodium laureth sulfate (SLES) in the previous discussion on PEG compounds. Here, it has added nothing new except to relate the material to sodium lauryl sulfate (SLS). As the starting alcohol is ethoxylated, the resultant surfactant becomes more water-soluble and less irritating. Since both of these surfactants are sold as aqueous solutions, there is no chance of any non-reacted ethylene oxide being present. Currently, the FDA reports 1,428 formulations containing SLS and 3,218 containing SLES. There are also replacement materials for these ingredients that, again, are more expensive, which poses a challenge to their application in the cost-competitive shampoo market.

Triclosan