Sodium Lauryl Sulfate: Facts versus Fairytales
Posted By Dr. Mercola | July 03 2010
By Dr. Mercola
Personal care products have become a $50-billion industry in the United States. You are seduced on a daily basis by the intoxicating aromas, flashy packaging and enticing promises of everlasting youth these products offer.
But what is the real cost of applying these products to your body?
If I were to tell you that your personal care products could be putting you at risk for hair and skin damage, immunological problems, damage to your eyes, and possibly even cancer, would you pay a little more attention to their ingredients?
The growing awareness of chemicals in the foods you eat has led many of you to begin reading labels. If you are doing this as part of your regular shopping routine, I commend you, and you will live longer for it.
But what about the products you are smearing all over yourself?
- Eye makeup can be absorbed by your highly sensitive mucous membranes.
- Hair sprays, perfumes and powders can be inhaled, irritating your lungs.
- Lipstick is licked off and swallowed.
- Sunscreen and lotions are absorbed through your skin.
- Shampoo can run into your eyes or your baby's eyes.
- Laundry detergent, in small amounts, comes in contact with your skin via your clothes
One of the findings was that the average adult uses nine personal care products each day, containing 126 different chemicals. The study also found that more than 250,000 women, and one out of every 100 men, use an average of 15 products daily.
Are these products as safe as the labels would have you to believe?
With the sheer multitude of chemicals out there, it would be impossible to cover them all in one report. But I have covered most of the significant players, and you can find those articles using the search engine at the top of this page.
This report will focus on a compound called sodium lauryl/laureth sulfate (SLS/SLES), a very common chemical used throughout the cosmetic industry.
A great deal of misinformation, myth and rumor surrounds SLS/SLES, and I would like to discuss what is really known about this chemical and it's potential risk to you.
What You Put ON Your Skin Can Be More Dangerous Than What You Eat
Putting chemicals on your skin or scalp may actually be worse than eating them. When you eat something, the enzymes in your saliva and stomach help to break it down and flush it out of your body. However, when you put these chemicals on your skin, they are absorbed straight into your bloodstream without filtering of any kind, going directly to your delicate organs.
Once these chemicals find their way into your body, they tend to accumulate over time because you typically lack the necessary enzymes to break them down.
There are literally thousands of chemicals used in personal care products, and the U. S. government does not require any mandatory testing for these products before they are sold.
The Environmental Working Group (EWG) estimates that one out of five cosmetics might be contaminated with a cancer-causing agent. This nonprofit public-interest research group is known for making connections between chemical exposure and adverse health conditions.
The United Nations Environmental Programme estimates that approximately 70,000 chemicals are in common use across the world, with 1,000 new chemicals being introduced every year. Of all the chemicals used in cosmetics, the National Institute of Occupational Safety and Health reported that nearly 900 are toxic, and that estimate might be low.
Many of the same poisons that pollute your environment are also lurking in the jars and bottles that line your bathroom shelves. We all risk becoming a toxic waste dump from the products we use, the foods we eat, and the environment in which we live.
Why Worry About Your Skin?
Your skin is much more than a wrap to keep you from sliding down into a puddle of formless bio-goo. It is your body's largest organ.
You might not be aware of the many protective functions your skin serves. Consider that your skin:
- Protects your internal organs from injury and infection and is your primary and most important defense against infections.
- Helps eliminate wastes through perspiration.
- Assists your immune system by providing a protective barrier to viruses and bad bacteria, thus preventing infections.
- Provides a friendly habitat for good bacteria.
- Helps maintain body temperature by controlling heat flow between you and your environment.
- Seals in moisture, maintaining your body's delicate fluid balance.
- Produces vitamin D, which is crucial for your health.
- Sends sensory feedback to your brain because it is rich in receptors, such as hard/soft and hot/cold, so that you can react to dangerous conditions around you.
Your skin is vital to your health, yet many people fail to take care if it. Because your skin has the ability to absorb much of what you put on it, informed choices are critical to optimize your health.
You should give your skin the same thoughtful care you give your diet, because much of what goes ON you ends up going IN you.
Choose Your "Natural" Cosmetics Carefully
There are no federal regulations for beauty products; anyone can claim their product is "natural" or "organic." A label with the word "natural" does not mean the product contains only natural or organic ingredients.
According to the Organic Consumers Association, whose current "Coming Clean Campaign" aims to clean up the organic personal care product industry, the word "organic" is not properly regulated with personal care products as it is with food products, unless the product is certified by the USDA National Organic Program.
In fact, some "organic" beauty products contain only a single-digit percentage of organic ingredients. Some brands use ingredients that were simply derived from natural sources but are highly processed and contain synthetic and petrochemical compounds.
When it comes to the labeling of cosmetics and body care products, it's kind of a free-for-all.
In a report released on March 14, 2008, the OCA found at least one toxic, cancer-linked chemical in over 40 percent of products that call themselves "natural."
Sodium Lauryl Sulfate (SLS), Sodium Laureth Sulfate (SLES), and Ammonium Laurel Sulfate (ALS)
Sodium lauryl sulfate is a surfactant, detergent and emulsifier used in thousands of cosmetic products, as well as in industrial cleaners. It is present in nearly all shampoos, scalp treatments, hair color and bleaching agents, toothpastes, body washes and cleansers, make-up foundations, liquid hand soaps, laundry detergents and bath oils/bath salts.
Although SLS originates from coconuts, the chemical is anything but natural.
The real problem with SLES/SLS is that the manufacturing process (ethoxylation) results in SLES/SLS being contaminated with 1,4 dioxane, a carcinogenic by-product, which will be discussed in more detail later.
SLS is the sodium salt of lauryl sulfate, and is classified by the EWG Cosmetics Database as a "denaturant, surfactant cleansing agent, emulsifier and foamer," rated as a "moderate hazard."
Similar to sodium lauryl sulfate (SLS) is sodium laureth sulfate (short for sodium lauryl ether sulfate, or SLES), a yellow detergent with higher foaming ability. SLES is considered to be slightly less irritating than SLS.
Ammonium lauryl sulfate (ALS) is another surfactant variation commonly put into cosmetics and cleansers to make them foam. ALS is similar to SLS, with similar risks.
SLS goes by other names, including:
Sodium dodecyl sulfate
Sulfuric acid, monododecyl ester, sodium salt
Sodium salt sulfuric acid
Monododecyl ester sodium salt sulfuric acid
Can 16,000 Studies About SLS be Wrong?
According to the Environmental Working Group's Skin Deep: Cosmetic Safety Reviews , research studies on SLS have shown links to:
- Irritation of the skin and eyes
- Organ toxicity
- Developmental/reproductive toxicity
- Neurotoxicity, endocrine disruption, ecotoxicology, and biochemical or cellular changes
- Possible mutations and cancer
If you visit the SLS page on the Environmental Working Group's (EWG) website, you will see a very long list of health concerns and associated research studies. In fact, you will also see their mention of nearly 16,000 studies in the PubMed science library (as well as their link to that list) about the toxicity of this chemical.
There are clearly grounds for concern about using products containing this agent. Yet, skeptics abound who claim that these concerns are overblown and unfounded. It's no wonder that consumers are completely confused about just how much risk this chemical poses.
Since most of the research studies are done on SLS itself—not on products containing it—the EWG states:
"Actual health risks will vary based on the level of exposure to the ingredient and individual susceptibility."
Many of the studies on laboratory animals have involved applying SLS directly to the eyes of the animals and feeding them straight SLS. As would be expected with ANY chemical, eating it or putting it in your eyes would be bad news!
Even natural substances applied in high concentration (for example, cinnamon oil or oregano oil) can have harmful effects.
But high levels of SLS intake, either orally or through the skin, are not ordinarily experienced in normal cosmetics use—it's the gradual,cumulative effects of long-term, repeated exposures that are the real concern. And there is a serious lack of long-term studies on ALL of the chemicals in these products—so we don't really know what the long-term effects are.
It's not just repeated exposure to one chemical—it's the combined effect of thousands of little chemical exposures, day in and day out, that is of concern.
Sorting through the evidence is even more complicated when research findings are exaggerated and misquoted, and then circulated around the Internet as if it were fact.
The Green Study Debacle
A huge source of misinformation arose from a gross misinterpretation (or misrepresentation) of a study done by Dr. Keith Green of the Medical College of Georgia, Department of Ophthalmology, which looked at the uptake of SLS by eye tissues. Paula Begoun (aka "The Cosmetics Cop") explains on her website how the Green controversy occurred.
Dr. Green investigated SLS uptake into the eye, but he did NOT study the effect of SLS on vision, nor did he study children or cataracts.
However, his findings were misquoted by anti-SLS zealots, to the point that he spent years trying to set the record straight about his findings and conclusions.
Dr. Green found that SLS is rapidly taken up and accumulated by eye tissues, where it is retained for up to five days. He also found that SLS uptake is greater in younger rabbits than in adult rabbits, and that SLS causes changes in some eye proteins.
However, someone quoted him as writing (in a report to the Research to Prevent Blindness conference):
"SLS is a systemic that can penetrate and be retained in the eye, brain, heart, liver, etc., with potentially harmful long-term effects. It can retard healing and cause cataracts in adults, and can keep children's eyes from developing properly."
Of course, this statement went far beyond the reaches of his study—and he denied ever saying it. The controversy that ensued led to a whole slew of articles and statements, based on this misinformation, that have done nothing but add to the confusion about SLS and fueling both sides of the issue.
Dr. Green later stated in an interview with Paula Begoun:
"There is no part of my study that indicated any eye development or cataract problems from SLS or SLES and the body does not retain those ingredients at all."
He also said that he did not even look at the issue with children, and later claimed his findings were so insignificant that he no longer had any interest in further researching the subject.
In spite of Green's later statements dismissing the importance of his findings, there are legitimate concerns about SLS and its systemic effects—based on multiple other studies.
The fact that one study's findings were misrepresented doesn't mean the risks aren't real. Naysayers are fond of citing the Green study debacle but NOT mentioning the other evidence of potential health risks of SLS.
Real Dangers of SLS—Rumors Aside
A number of studies report SLS being damaging to oral mucosa and skin. This is not at all surprising since SLS is actually used as a skin irritant during studies where medical treatments for skin irritation require an intentionally irritating agent.
- A study at the Stern College for Women at Yeshiva University in New York in 1997 examined SLS in mouthwash. They found that SLS in mouth rinses caused desquamation of oral epithelium and a burning sensation in human volunteers.
- A study appearing in Exogenous Dermatology confirmed SLS to be a very "corrosive irritant" to the skin—irritation which persisted in research subjects for 3 weeks. SLS exerts its damage by stripping your skin of protective oils and moisture.
- SLS is associated with increased aphthous ulcers (canker sores) due to the denaturing effect and irritation of the oral mucosa.
Swallowing SLS will likely lead to nausea and diarrhea and is even used as a laxative in enemas. So be careful not to swallow much of your toothpaste if it contains SLS.
According to Judi Vance, author of Beauty to Die For, SLS can cause cellular DNA damage. In an article for ConsumerHealth.org, she states that a dental association in Japan tested the effects of SLS on bacteria, finding it to be mutagenic. She also states that hair follicles are significant transporters of harmful chemicals into your body.
Links Between SLS, Ethylene Oxide, 1,4 Dioxane, and Cancer
The evidence linking SLS to cancer is a bit challenging due to the paucity of scientific studies. However, carcinogenic effects are quite possible when you consider that SLS/SLES is often contaminated by two known carcinogens:
1. Ethylene oxide (which is what the "E" in SLES represents). A return to the Skin Deep website for ethylene oxide reveals a rating of "high hazard," which appears as an impurity in thousands of personal care products. It is used to "ethoxylate" SLS and other chemicals, to make them less harsh.
2. 1,4 dioxane, a byproduct of ethylene oxide, also receives a "high hazard" rating from Skin Deep and is associated with an even longer list of common personal care products. On the CDC site, 1,4 dioxane is described as "probably carcinogenic to humans," toxic to the brain and central nervous system, kidneys and liver. It is also a leading groundwater contaminant.
To avoid 1,4 dioxane, the Organic Consumers Association (OCA) recommends avoiding products with indications of ethoxylation.
To do this, look for the following suffixes in the ingredient list: "myreth," "oleth," "laureth," "ceteareth," any other "eth," "PEG," "polyethylene," "polyethylene glycol," "polyoxyethylene," or "oxynol."
For example—sodium laureth sulfate.
The FDA continues to take the stance that the levels of 1,4 dioxane in body care products are too low to be considered harmful. But given that there are products available that have NO 1,4 dioxane, why take a chance with your health?
Your best bet is to purchase products that are certified under the USDA National Organic Program, and if those aren't available, select products whose ingredients you recognize—and can pronounce!
SLS and Nitrosamines
SLS has also been linked to nitrosamines. Nitrosamines are potent carcinogens that cause your body to absorb nitrates, which are known to be carcinogenic as well.
According to one article by Greenfeet, at least one study linked SLS to nitrate absorption.
The Greenfeet article states:
"A study citied in the Wall Street Journal (November 1, 1988) linked SLS to cataracts and nitrate absorption (nitrates are carcinogens—or cancer causing substances). Apparently, this absorption occurs when the SLS becomes contaminated with NDELA (N-nitrosodiethanolamine) during processing.
This contamination comes about as a result of SLS coming into contact with any number of chemicals including TEA (triethanolamine,), which is a commonly used ingredient in shampoos as a detergent."
So, the SLS combines with the TEA, resulting in NDELA, which is a nitrosamine and a recognized carcinogen.
The biochemistry is very complex due to the "chemical cocktail" that is your shampoo or hand wash. When these chemical ingredients come into contact with each other, all sorts of molecular bonds begin to form and new and unintended chemicals are produced.
Unfortunately, some of these unintended chemicals are nitrosamines.
As the above article points out, there is no way the FDA can possibly test all of the combinations of chemicals available, in every unique blend.
So, while the individual ingredients may be considered safe, once you mix them up into a brew, all bets are off. Just because SLS doesn't contain nitrogen, doesn't mean it can't GET a nitrogen from the chemical soup and bond with it to form deadly nitrosamine.
How to Evaluate Your Toxic Toiletry Burden
Lest you shrug these findings off, thinking that your exposure is "insignificant," think again.
Did you know that, if you use conventional cosmetics on a daily basis, you can absorb almost 5 pounds of chemicals and toxins into your body each year?
Daily use of ordinary, seemingly benign personal care products like shampoo, toothpaste and shower gel can easily result in exposure to thousands of chemicals, and many will make their way into your body and become "stuck" there, since you lack the means to break them down.
This toxic load can become a significant contributing factor to health problems and serious diseases, especially if your diet and exercise habits are lacking.
Women seem to be predisposed to more autoimmune disorders than men. Diseases such as thyroid disease, fibromyalgia, and multiple sclerosis are far more common in women. Perhaps one of the major contributing factors is that women tend to use far more personal products than men.
If you are a woman, acting on the information in this report is particularly important. Is your make-up cabinet a toxic wasteland?
It is especially challenging to establish a link between these routine chemical exposures and health problems down the road, because the adverse effects might not show up for years.
As Theo Colburn discusses in Our Stolen Future, in some cases, effects are not seen in the person exposed but DO appear in her offspring. This has been seen in the animal kingdom, as well as in humans. Some adults have been known to suddenly show a disease many decades after prenatal exposure.
If you would like to learn more about the health effects of the chemicals you are routinely exposed to, I strongly urge you to read Our Toxic World: A Wake Up Call by Dr. Doris Rapp. She does a thorough job of uncovering the many ways we are exposed to toxic chemicals and how they contribute to chronic disease.
A Newer, Greener YOU!
With the jury still out about long-term exposure to SLS and its associated contaminants, the best advice is to avoid them and avoid the risk altogether—since there are safe alternatives available.
The easiest way to ensure that you're not being exposed to potentially hazardous agents is to make your own personal care products, using simple all-natural ingredients that you may already have in your home.
Finding recipes for your own homemade beauty products is a breeze when you have access to the Internet. Just Google "homemade cosmetics" for more than 400,000 pages of recipes and instructions.
If whipping up lotions and potions isn't your bag, be sure to read labels and check products out before buying them. The website mentioned above,
(Send your news to [email protected], Foodconsumer.org is part of the Infoplus.com ™ news and information network)
- Pumpkin seed extract fights prostate cnacer, breast cancer, colorectal cancer
- What temperature to Cook a Turkey - Safe Cooking
- Angiotensin Receptor Blockers (ARBs): Ongoing Safety Review for Cancer Risk
- Light Therapy Promising for Treating Major Depression
- Desserts: Chocolate Pudding