Sodium Lauryl Sulfate
By David Steinman, from Healthy Living
Talk to many health-conscious consumers
today about personal care products and one of their main topics of
concern is use of the allegedly dangerous shampoo ingredient, sodium
lauryl sulfate. But is sodium lauryl sulfate truly dangerous or has it
received a bad rap? Or does the answer lay somewhere between these two
This is not an inconsequential question, since our recent marketplace
review of more than 100 leading brands of shampoos indicates that most
contain this ingredient. The reason sodium lauryl sulfate is used, we
believe, is because it is an inexpensive detergent and makes mixtures
All shampoos are irritating. Shampoos rank among the products most often
reported to the Food and Drug Administration for association with scalp
irritation, stinging eyes, and tangled, split, and fuzzy hair. Most
shampoos contain synthetic detergents for washing hair. But is sodium
lauryl sulfate the culprit when it comes to irritation?
What Science Says About Sodium Lauryl Sulfate
In its final report on the safety of sodium lauryl sulfate, the
Journal of the American College of Toxicology
notes that this ingredient has a "degenerative effect on the cell
membranes because of its protein denaturing properties." What's more,
the journal adds, "high levels of skin penetration may occur at even low
Interestingly, sodium lauryl sulfate "is used around the world in
clinical studies as a skin irritant," notes the journal. The publication
expressed additional concerns:
Carcinogenic nitrosamines can form in the manufacturing of sodium
lauryl sulfate or by its inter-reaction with other nitrogen-bearing
ingredients within a formulation utilizing this ingredient.
Other studies have indicated that sodium lauryl sulfate enters and
maintains residual levels in the heart, liver, lungs and brain from
skin contact. This poses the question whether it could be a serious
potential health threat from its use in shampoos, cleansers, and
Still other research has indicated sodium lauryl sulfate may be
damaging to the immune system, especially within the skin. Skin
layers may separate and inflame due to its protein denaturing
Although sodium lauryl sulfate is not carcinogenic in experimental
studies, it has been shown that it causes severe epidermal changes
in the area it is applied, indicating a need for tumor-enhancing
Additional studies have found that sodium lauryl sulfate is heavily
deposited on the skin surface and in the hair follicles. Damage to
the hair follicle could result from such deposition.
Threat to Eye Health
Damaging effects of sodium lauryl sulfate on eye health are also of
concern. In experimental, acute eye tests, a solution of 10 percent
sodium lauryl sulfate "caused corneal damage to the . . . eyes if not
irrigated or irrigation was delayed."
A solution of 5.1 percent "caused mild irritation."
There may be another more insidious problem with use of sodium lauryl
sulfate. Bear with us if we use a little scientific lingo in this
section of the report. Your reward will be a better appreciation for
whether sodium lauryl sulfate poses undesirable health effects. Often,
in order to make a shampoo gentle to the eyes, the manufacturer will
utilize a combination of anionic surfactants (i.e., detergents) with
nonionic detergents. An anionic detergent contains a negatively charged
polar group. A nonionic detergent has no polar end. Anionic detergents
"display remarkable detergent, emulsifying, and foaming properties."
"generally considered as the mildest of all surfactants" whose use "has
been restricted because of poor foaming potential. They serve more often
as auxiliary detergents."
However, while anionic detergents such as sodium lauryl sulfate are the
most irritating to the eye, nonionic detergents are less irritating.
What's more, according to Tom Conry, author of Consumer's Guide to
Cosmetics, "Some of the nonionic surfactants are believed to
anesthetize the eyeball. Although we have not been able to track down
all of these anesthetizing surfactants, the most common ones are
cocamide MEA and DEA, and lauramide MEA and DEA." This is why anionic
detergents are frequently combined with nonionic detergents to make
shampoos gentle to the eye. In essence, while more aggressive anionic
detergents like sodium lauryl sulfate are irritating the eye, the
eyeball has been anesthetized by nonionic detergents also in the
formulation. Look at shampoo labels and such combinations will be
Further, according to the Journal of the American College of
Toxicology, "Tests show permanent eye damage in young animals from
skin contact in non-eye areas. Studies indicated sodium lauryl sulfate
kept young eyes from developing properly by possibly denaturing the
proteins and not allowing for proper structural formation. This damage
Substitution of Gentler Detergents Poses Additional Risks
Unfortunately, many of the gentler detergents that may be substituted
for sodium lauryl sulfate pose their own health hazards. For example,
many companies have begun to use ethoxylated detergents such as
sodium laureth sulfate, cocamide DEA
or lauramide DEA because they tend to be less irritating.
Consumers can recognize shampoo ingredients containing ethoxylated
detergents and related ingredients by looking for the prefix, word, or
syllable PEG, polyethylene, polyethylene glycol, polyoxyethylene, eth
(as in sodium laureth sulfate), or oxynol.
Both our own commissioned independent laboratory testing and that of the
federal government have documented ethoxylated alcohol compounds are
frequently contaminated with
1,4-dioxane, which is carcinogenic and is listed by the federal
government as a probable human carcinogen.
Also, according to a 1998 report from the federal National Toxicology
Program, two DEA-based compounds‹cocamide DEA and lauramide DEA‹have
been demonstrated to be cancer-causing in at least in one species of
The Doctors' Prescription for Healthy Living/ Safe Shopper's Bible
According experts on the Cosmetic Ingredient Review (CIR) panel
(established by the Cosmetic Toiletry, and Fragrance Association, a
cosmetic industry trade association), both sodium lauryl sulfate and its
close chemical cousin ammonium lauryl sulfate
"appear to be safe in formulations designed for discontinuous, brief use
followed by thorough rinsing from the surface of the skin."
It should be recognized that shampoos represent such brief,
discontinuous use products that are thoroughly rinsed, thus clearly
minimizing the risk from sodium lauryl sulfate. It should also be
recognized that many people shampoo daily, and we really do not know
whether a lot of little exposures to sodium lauryl sulfate are dangerous
Given the lack of adequate research and suggestive evidence, however, we
believe it might be wise for health-conscious consumers to seek products
without sodium lauryl sulfate, especially with regard to young children.
Indeed, consumers have the power to choose safe and perhaps even better
products without sodium lauryl sulfate.
This may be a very wise choice for another reason. We have found very
often the presence of sodium lauryl sulfate in a shampoo formulation is
a "marker" for the use of other undesirable ingredients, including
formaldehyde-containing preservatives (e.g., imidazolidinyl urea);
possible cancer-causing wetting agents (e.g., cocamide DEA); and
nitrosamine-forming agents (e.g., triethanolamine). Also, it should be
mentioned that in Germany, where there is a concerted effort underway
now to label cosmetics and personal care products as certified natural,
formulations containing sodium lauryl sulfate, ammonium lauryl sulfate
or sodium laureth sulfate cannot be so certified, reports Michael
Wrightson, president of Logona Kosmetik.
"Bioassay of 1,4-Dioxane for possible carcinogenicity (CAS No.
123-91-1)." National Toxicology Program, TR-80.
C. "Shampoos and hair conditioners." Clinics in Dermatology, 1988; 6(3):
Consumer's Guide to Cosmetics. Garden City, NY: Ancor Press / Doubleday,
1980, p. 74.
report on the safety assessment of sodium lauryl sulfate." Journal of
the American College of Toxicology; 1983; 2(7).
Annual Report on Carcinogens, 1991. Summary. U.S. Department of Health
and Human Services, Public Health Service. National Institute of
Environmental Health Sciences, Research Triangle Park, NC, 1991, pp.
lauryl sulfate ammonium lauryl sulfate."1996 CIR Compendium. Washington,
D.C.: Cosmetic Ingredient Review, 1996, pp. 134-135.
"Toxicology and carcinogenesis studies of coconut oil acid
diethanolamine condensate (CAS NO. 68603-42-9) in F344/N rats and B6C3F1
mice (dermal studies)." National Toxicology Program, TR-479.
"Toxicology and carcinogenesis studies of lauric acid diethanolamine
condensate (CAS NO. 120-40-1) in F344/N rats and B6C3F1 mice (dermal
studies)." National Toxicology Program, TR-480.
For products without
sodium lauryl sulfate or any other controversial ingredients