Here I will debunk some of the more dubious claims in the forwarded email. Please note that this is not a general article about the pros and cons of shampoo ingredients, or even of this particular ingredient. I will address specific allegations in the email text, the main one being that sodium laureth sulfate is carcinogenic. Sources and links for further reading are at the bottom of this page and in the sidebar to the right.
- Q: Is sodium laureth sulfate commonly found in shampoos and toothpastes?
A: Shampoos, frequently; toothpastes, occasionally. (It's much more common to find the harsher surfactant sodium lauryl sulfate in toothpastes.)
- Q: Is sodium laureth sulfate known to cause cancer?
A: No. The chemical does not appear on any official list of known or suspected carcinogens.
- Q: Is sodium laureth sulfate properly abbreviated as "SLS?"
A: No. The correct abbreviation is "SLES." The chain letter confuses this compound with another: sodium lauryl sulfate, which is abbreviated "SLS." The two substances are related, but not the same.
- Q: Is sodium laureth sulfate used to scrub garage floors?
- Q: What about the other one - sodium lauryl sulfate - is it used to scrub garage floors?
A: No doubt! SLS is a powerful surfactant (wetting agent) and detergent. It is used in both industrial cleaning products and, in lesser concentrations, personal care products.
- Q: Is sodium lauryl sulfate commonly found in shampoos and toothpastes?
A: Yes, both. It's also found in shaving creams and other lathering products.
- Q: Ah. Well, then, is SLS a known carcinogen?
A: No, it is not on any official list of known or suspected carcinogens. But it is a harsher chemical than SLES, which is why SLES is typically used in baby shampoos instead. Sodium lauryl sulfate is well known to be a skin and eye irritant and can cause dermatitis with prolonged contact in high concentrations. Results of some tests on animal tissues indicate that it's mutagenic - i.e., it may be related to abnormal cell mutations - though the evidence is inconclusive. Even so, scientists familiar with the substance insist it is not dangerous in the concentrations found in personal care products.
- Q: Would a manufacturer freely admit to consumers, as claimed in the message, that it knowingly uses a carcinogen in its products "because we need that substance to produce foam?"
A: Of course not.
Q: Is it true that my chances of getting cancer are "1 out of 3" in the '90s?
A: Yes, with a few qualifications. The problem with stating probabilities in this case is that there's no way to generalize accurately. The reasons are: 1) cancer risks for individuals vary according to a host of factors, including gender, race, habits, and family history; and 2) the likelihood of any individual contracting cancer is also a function of their age. For example, if you're 20 years old, the odds are much greater that you'll contract cancer in your lifetime than they are if you're 50, simply because there's a longer time span involved.
That said, the longer answer is: For an "average person" (that is, someone of no particular age or gender who lives nowhere in particular and inherited no genes from his or her parents), the chances of getting cancer over a lifetime work out to somewhere between 1 in 3 and 1 in 2, at present.
- Q: Were the chances of getting cancer in the 1980s "1 out of 8,000?"
A: No, that's absurd. Cancer rates were approximately the same two decades ago as they are now; if anything, they were a bit higher.
- Q: Really? Aren't cancer rates rising?
A: No, in the United States they have been falling, though at a fractional rate and there's no telling if that trend will continue.
- Q: Is the chain letter a hoax?
A: Most likely. At the very least it contains egregiously inaccurate information. But we can only guess at the motives of whoever launched it.
Q: Where did the misinformation come from?
A: Well, if you're asking who started the chain letter, there's no way of knowing. As to the misinformation itself, it turns out that there are a good many Web pages containing very similar - and in some cases identical - statements. It's a good bet that it all came from the same source at some point in time.
Interestingly, all these Websites are maintained by "independent distributors" for multi-level marketing companies hawking "natural" personal care products, etc. As a matter of fact, the majority of URLs returned in a standard Web search on the keywords "sodium laureth sulfate" point to versions of the same propaganda. Assuming all this information did come from the same source, the author of our chain letter and some of these Web entrepreneurs are sloppy copyists at the very least, and/or intent on slanting the "facts" to suit their purposes.
In the chain letter, for example, the cancer rate in the 1980s is alleged to be "1 out of 8,000"; the Web pages tend to say that was the cancer rate in 1901. That sounds more reasonable, but it's no cause to assume the Websites are entirely accurate. On some of them, the ratio cited for 1901 is not "1 out of 8,000," but "1 out of 80." Again, some of these authors are either making it up as they go along, or copying the information very carelessly.
Misinformation has a way of multiplying.
Many of the pages I looked at were littered with inaccuracies, deceptive statements and outright lies. One even alleges that "In 1993 it was documented that sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) were the leading cause of blindness in children" - as if claiming they're carcinogens weren't inaccurate enough. Another page links prominently to a site vending quack cancer cures. In some cases, the texts cite legitimate medical studies, but in a misleading way, making it appear as if the studies prove much more than they actually did.
Small wonder that by the time this information made its way into chain letter form, virtually every statement in it was outrageously false.
What's worse, as the chain letter circulates, the information continues to degrade. One of the more recent variants of the email gives the abbreviation of sodium laureth sulfate as "SLY," which is doubly wrong.
- Q: Do you think the chain letter may have been deliberately started to frighten people into using other products?
A: I suspect it, but there's no way to know for sure, and I can't prove it. For all we know, someone came across this stuff by accident, innocently believed it to be true, and decided to share it with others.
- Q: Do you really think that was the case?
A: I doubt it.
Postscript: The old adage, "Where there's smoke, there's fire," may apply here. While the "facts" stated in the sodium laureth sulfate warning are almost entirely false, there may be other potentially hazardous substances in name-brand personal care products. For more information, see the following:
Sources and further reading:
- 8th Annual Report on Carcinogens (1998). National Toxicology Program. URL: http://ntp-server.niehs.nih.gov/Main_pages/NTP_8RoC_pg.html
(1 Sep. 1998).
- "Study: U.S. Cancer Rates Declining." CNN News, 13 Mar. 1998. URL: http://www.cnn.com/HEALTH/9803/13/less.cancer/
(7 Sep. 1998).
- Clayton, R.M., et al. (1985). "The Penetration of Detergents into Adult and Infant Eyes." Food and Chemical Toxicology 23.2 (Feb. 1985): 239-246.
- Friedlander, Ed. "Sodium Lauryl Sulfate - Not a Cancer Risk." The Pathology Guy. URL: http://www.pathguy.com/sls.htm (8 April 2001).
- Hope, J. "Absence of Chromosome Damage in the bone marrow of rats fed detergent actives for 90 days." Mutation Research 56.1 (Sep. 1977): 47-50.
- Material Safety Data Sheet for Sodium Dodecyl Sulfate (Sodium Lauryl Sulfate). URL: http://www.vwrsp.com/ (1 Sep. 1998).
- "New Report on Declining Cancer Incidence and Death Rates..." National Cancer Institute Press Release, 12 Mar. 1998. URL: http://rex.nci.nih.gov/massmedia/pressreleases/deathrate.html
(7 Sep. 1998).
- "Sodium Lauryl Sulfate." American Cancer Society. URL: http://www2.cancer.org/zine/index.cfm?fn=004_09231998_0 (8 April 2001).
- UMCP Partial List of Teratogens (1995). University of Maryland. URL: http://www.inform.umd.edu/DES/ch/terat.html (4 Sep. 1998).
- Winter, Ruth. A Consumer's Dictionary of Household, Yard and Office Chemicals. New York: Crown, 1992.
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