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Nicht richtig ist hingegen, dass SLS und SLES Krebs auslösen. Jedenfalls gibt es keine ernst zu nehmenden wissenschaftlichen Studien, die eine kanzerogene (krebserregende) Wirkung dieser Substanzen belegen [1]. Ebenso wenig gibt es Nachweise, dass durch SLS oder SLES "Grauer Star" ausgelöst wird (wenn man es sich nicht täglich in konzentrierter Lösung in die Augen träufelt...).
Einer der möglichen Gründe, warum SLS unter Krebsverdacht geraten ist, kann der Umstand sein, dass in den 1970er Jahren teilweise Ethanolamin statt Natrium eingesetzt wurde. Dieses Ethanolaminlaurylsulfat kann (im Gegensatz zu SLS und SLES) krebserzeugende Nitrosamine als Verunreinigung enthalten. Es wird jedoch bereits seit mehreren Jahrzehnten nicht mehr in Kosmetika eingesetzt. [3]

Sehr auffällig ist, dass eine große Zahl der Webseiten, die man bei Suche nach Laurylsulfat findet und die es verteufeln, zu angeblich "unabhängigen" Vertriebsagenten von angeblichen "Öko-" oder "Natur"produkten gehören [2]. Diese Produkte werden per Network-Marketing ("MLM": Multi-Level-Marketing, auch "Empfehlungs-Marketing") unters Volk gebracht. Das erklärt auch, warum die Texte weitgehend identische Formulierungen enthalten: Sie sind schlicht aus den Werbetexten der Hersteller abgeschrieben oder kopiert.

Fazit: Natriumlaurylsulfat & Co. sind nach aktuellem Stand der wissenschaftlichen Erkenntnis nicht krebserregend [1]. Das bedeutet jedoch nicht, dass diese Substanzen völlig harmlos und ihre Verwendung in jeder Hinsicht unbedenklich wäre.

# [1] engl. American Cancer Society: über SLS/SLES | über Fehlinformationen
# [2] engl. UrbanLegends.About, liefert etliche weiterführende Quellen
# [3] engl. Urban Legends Reference (Snopes)

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In fact, three different agencies - the Occupational Safety and Health Administration (OSHA), the National Toxicology Program (NTP), and the International Agency for Research on Cancer (IARC) have all rated SLS as being non-carcinogenic.

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Well, how about the writer's claim that "I called the company and told them their product contains a substance that will cause people to have cancer, and they say they know it but there is nothing they can do about it. They need that product to produce foam"? Didn't these shampoo manufacturers learn anything from the tobacco companies, who denied admitting that cigarette smoking causes cancer despite all the evidence to the contrary (and despite the warning labels that cigarette packages have been required to carry for over thirty years now)? If the government allowed shampoo companies to sell products containing known carcinogens without requiring them to place warning labels on their products, why in the world would they freely admit it to anyone who asked?

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So where does the idea that SLS is carcinogenic come from? Back in the 1970s some shampoos were found to be contaminated with small amounts of nitrosamines, which are carcinogenic. Ethanolamine lauryl sulfates used in these shampoos were determined to be the source of the nitrosamine contamination, and manufacturers took corrective action. Perhaps someone is now confusing ethanolamine lauryl sulfate with sodium lauryl sulfate. Or, since the "SLS is dangerous" message has been widely disseminated by sellers of "alternative" or "all natural" products who tout that their wares don't contain SLS, perhaps someone in the "natural products" business deliberately created the message as a way of drumming up sales. There's nothing like an unfounded medical scare to get those cash registers ringing, and you can altruistically claim you have your customers' best interests at heart while you fleece them.

Wherever this notion came from, there simply is no medical evidence that SLS poses a significant risk of cancer to consumers of household products such as shampoo and toothpaste.

# Goldemberg, Robert.   "Minimizing Irritation in Cosmetic Foundations."; Drug & Cosmetic Industry.   Vol. 156; 1 January 1995   (p. 37).
# Henrickson, Eric.   "Edible Bubbles Add Tasty Twist to Timeless Fun."; Gannett News Service.   20 February 1997.
# Murray, Caryn Eve.   "It Doesn't Have to Be Hair Today, Gone Tomorrow."; Newsday.   24 March 1996   (p. 28).
# Oldenburg, Don.   "Rhetoric or Reality?"; The Washington Post.   21 October 1998   (p. D6).
# Oldenburg, Don.   "How Safe Is Toothpaste?"; St. Louis Post-Dispatch.   19 July 1997   (p. 35).
# Schwarz, Joe.   "Secrets of Shampoo."; The Washington Post.   9 December 1998   (p. H1).

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Rumors have circulated widely on the internet that SLS/SLES are carcinogenic. They have spread through chain emails citing a fake report supposedly published by the Journal of the American College of Toxicology. No legitimate evidence can be found to support this claim. In response to the rumour, the Cosmetics Toiletry and Fragrance Association (CTFA) and the American Cancer Society have confirmed it to be an urban legend.
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