Sodium Lauryl Sulfate
(SLS), Sodlium Laureth Sulfate (SLES) Effects on Health
and Hair Loss
Debunking
SLS as a carcinogen
Firstly,
let's debunk a major urban legend with regards to Sodium
Lauryl Sulfate ("SLA") or Sodium Laureth Sulfate
("SLES"). There is no evidence that they cause
cancer. The mania about SLS/SLES being a cacinogen has
been attributed to Neways promoting their all natural
products on the internet. Findings
of a study published by the Medical College of Georgia
was completely misquoted.
This
was followed by mass email circulated to perpetuate
the myth. Health Canada invested resources to investigate
this and in a press release, February 12, 1999 (http://www.hc-sc.gc.ca/)
stated, "...Health Canada has looked into the matter
and has found no scientific evidence to suggest that
SLS causes cancer. .... Upon further investigation,
it was discovered that this email warning is a hoax.
The letter is signed by a person at the University of
Pennsylvania Health System and includes a phone number.
Health Canada contacted the University of Pennsylvania
Health System and found that it is not the author of
the sodium laureth sulphate warning and does not endorse
any link between SLS and cancer..."
Further,
according to the American Cancer Society's Web site,
"Contrary to popular rumors on the Internet, Sodium
Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES)
do not cause cancer. Emails have been flying through
cyberspace claiming SLS [and SLES] causes cancer...
and is proven to cause cancer. ...[Yet] A search of
recognized medical journals yielded no published articles
relating this substance to cancer in humans."
Difference
Between SLS and SLES
Often
writers confuse the ingrediant commonly found in shampoos,
sodium laureth sulfate by abbrevating it as "SLS"
when it should be "SLES". Both SLS and SLES
are derived from coconut oil but produced from different
processes. SLS is cheaper to produce and drives the
mass market as a cleaning agent, infamously as a popular
floor cleaning agent. SLES is more compatible to the
skin and causes less skin irritation and hence its relative
popularity as the ingredient of choice in shampoos.
SLS
as an Irritant
Having
said all that, sodium lauryl sulfate is a potent skin
irritant (but sodium laureth sulfate is less so because
it has a different chemical structure that results in
a gentler cleansing agent). It is considered a standing
comparison substance for measuring skin irritancy of
other ingredients. In scientific studies when they want
to establish whether or not an ingredient is problematic
for skin, they compare its effect to the results of
SLS. In amounts of 2% to 5% it can cause irritating
or sensitizing reactions in lots of people (Sources:
European Journal of Dermatology, September-October 2001,
pages 416-419; American Journal of Contact Dermatitis,
March 2001, pages 28–32).
Conclusion
SLS
and SLES do not cause cancer. However they are proven
irritants. Since our hair calls for gentle care to maintain
its health, it is conceivable that frequent use of shampoos
with even the more popular SLES (for shampoo use) can
conceivably cause irritation to sensitive scalps. Users
who wish to err on the side of caution may want to try
SLS/SLES-free products. For sure, SLES is a cheap and
effective cleaning agent that keeps the prices of shampoos
low.
Important read on better hair care below:
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