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SODIUM
LAURYL SULFATE -
The
Straight Story
Dr. Dennis T Sepp
Sodium lauryl
sulfate (SLS) is a detergent which is commonly used as a cleansing agent in all
sorts of personal care products. It appears in toothpastes, shampoos, bubble baths,
shaving creams -- any product that requires suds. It is very effective and also very
cheap. Most SLS is made from coconut oil because it is rich in the fatty acid called
lauric acid.
The production of SLS
begins with heating coconut oil in water in the presence of sodium hydroxide. This
converts the coconut oil into fatty acids (lauric acid and glycerin). The fatty acids are
next converted into fatty alcohols by a process called hydrogenation. These fatty alcohols
(lauryl alcohol) are waxy materials that are excellent moisturizers. For example,
cetyl
alcohol is a commonly used and effective moisturizer in lotions and creams. Lauryl
alcohol is then converted into lauryl sulfate by a process called sulfonation. In the
final step, lauryl sulfate is reacted with sodium hydroxide to produce sodium lauryl
sulfate. When lauryl sulfate is reacted with ammonia instead of sodium hydroxide you have
ammonium
lauryl sulfate. Likewise, when triethanol amine (TEA) is used, you have
TEA lauryl
sulfate. Both of these are also commonly used cleansing agents.
There have been safety
issues raised about the use of SLS. Some of these issues are valid and some are clearly
erroneous. The reports and rumors that SLS can cause blindness as well as cancer are not
substantiated and simply not true. I know of no legitimate studies or publications which
support these reports. Typically, such a rumor appears on the internet or in a sales sheet
produced by a company trying to capitalize on a "we don’t use SLS" claim.
The real problem with SLS is that it is too strong a cleansing agent which too easily
strips oils from skin and hair. This can be a genuine problem in bubble baths. Because SLS
is so cheap and makes such great bubbles, manufacturers tend to use a lot of it in these
formulas. The result can be skin irritation for a child (or anyone) who frolics too long
in their bath.
I don’t use sodium
lauryl sulfate in any of my formulas because of this. There are other cleansing and
sudsing agents which work just as well. In the lauryl sulfate family, I prefer TEA lauryl
sulfate. This is considerably more expensive but is much milder and less irritating to the
skin.
Dennis T. Sepp, PhD, Medicinal Chemistry
ShiKai Products |
