2002 Dr. Sam Epstein's Explanation to the Hazards of SLS - Sodium Laurel Sulfate 

Following is Dr. Epstein's answer regarding the degree of SLS toxicity. 

Regarding  Sodium Lauryl Sulfate, there is no evidence that SLS is carcinogenic.
However, contrary, SLS is a harsh ionic detergent which is a strong irritant to skin, depending on concentration and the duration of exposure. The Cosmetic Ingredient Review (CIR) 2000 Compendium, of the Cosmetic, Toiletry and Fragrance Association, admits that SLS "causes severe epidermal changes--of the skin of mice--(indicating) a need for tumor-enhancing activity assays," (1). The Compendium also admits that SLS containing products are "designed for brief discontinued use, following which they are thoroughly rinsed
from the surface of the skin."

Furthermore, as reported in model studies, published by the Danish Institute of Public Health, a single 24-hour exposure of SLS to human skin damages skin protein and causes prolonged disruption of "the skin barrier integrity of the skin," to allow the penetration of carcinogens such as nickel and chromate (2,3). Thus, skin absorption of the multiple carcinogenic ingredients commonly found in mainstream industry cosmetics and toiletry products (4), including shampoos, could be greatly increased by SLS type detergents.

 Clearly, the American Cancer Society is unaware of this information, besides the fact that mainstream industry cosmetics and toiletries contain a wide range of carcinogenic ingredients, precursors, and contaminants, besides ingredients that break down to release carcinogens such as formaldehyde. 

Furthermore, laureths, besides other ethoxylated alcohols, are generally contaminated by the volatile carcinogen 1,4-dioxane, as admitted by the CIR Compendium (1), and also the carcinogen ethylene oxide.

Samuel S. Epstein, M.D.

1. CTFA. Cosmetic Ingredient Review (CIR) Compendium 2002.

2. Nielsen, G.D. et al. Effects of Industrial Detergents on the
Barrier Function of Human Skin. Int. J. Occup. Med. 6(2):138-142, 2000.

3. Nielsen, G.D. Effects of Four Detergents on the In-Vitro
Barrier Function of Human Skin. Int. J. Occup. Med. 6(2):143-147, 2000.

4. Epstein, S.S. and Steinman, D. The Safe Shopper's
Bible. Macmillan/Hungry Minds, Inc., New York, 1995.

5.  Unreasonable Risk, Avoidable Risks of Cancer, 2002.

6.  Unreasonable Risk, 2nd edition, 2005

7.  Cancer Gate- How to win the Losing Cancer  War

8.   What's In your Milk?

Llike soap, sls can sting if it gets into your eyes and that, at higher
concentrations than you'll find in any shampoo, SLS can irritate the skin.

Compare this to similarly alarming reports about //vm.cfsan.fda.gov/~dms/cos-dea.html" >diethanolamine (DEA), another shampoo
component. Here, a study from the National Toxicology Program linked http://ntp-server.niehs.nih.gov/main_pages/about_NTP.html"
residual levels of DEA to cancer in laboratory animals.

Although the study didn't even address the question of whether
DEA can cause cancer in humans, the FDA announced that it would evaluate the data to determine the risk, if any, to consumers. They have seen the peer reviewed studies on the carcinogenicity of DEA, but say they still need more proof that it causes cancer. Meanwhile, all they will do is require a "warning label" on products containing DEA, Mineral Oil, etc.

SLS has a long history of use in shampoos and other personal care products  without proper testing or controls.

I don't think you need to worry about it. If you'd rather not take any chances, you should have no trouble finding alternative products that do not contain it.

For Safe Products without SLS or harmful ingredients