There is no cancer risk from SLS (Sodium Lauryl Sulfate)
September 21st, 2010I now duck as the tomatoes start to fly.
You might call it a brilliant stroke of marketing genius. You might call it a widespread hoax. Sodium Lauryl Sulfate (SLS) is surrounded by some of the greatest confusion and mis-information in the industry. In short, SLS has a very bad reputation, and it is such a phenomenon that I think somebody should write a book on it. It has become more vilified than any other chemical in bodycare, while those that are much more problematic pass freely beneath the radar.
The most damaging claim against SLS is that it is carcinogenic, because it supposedly creates nitrosamines. However, since it contains neither a nitrogen nor an amino group, this is chemically impossible.
|
SLS is in our Sal Suds all purpose cleaner, and here’s what we say about it on the bottle: Sodium Lauryl Sulfate (SLS) is a surfactant that cuts grease and dirt, generates copious suds, and biodegrades quickly and completely. SLS is made by combining a sulfate group with lauryl alcohol from coconut oil, then attaching sodium. If improperly formulated, SLS can irritate skin, but our superb formula uses coco-betaine and lauryl glucoside to counter this. Sal Suds is a mild, synthetic detergent, not a bodycare product. SLS does not, and never has, appeared in any of our soaps since the saponified vegetable oils in our castile soaps are much, much better for our skin, and can be certified organic. SLS is synthesized (read “man made” or “processed”) even though it does have a coconut base. |
![]() |
I think this article has a good overview of the rumors: http://www.pathguy.com/sls.htm This page is written by Ed Friedlander, a pathologist from the Kansas City University of Medicine and Biosciences http://www.kcumb.edu/faculty/facultydetails.asp?id=12. I haven’t met him. He may or may not know about Dr. Bronner’s. (Take note that David Steinman, to whom Ed refers at the end, has done a great deal of excellent research and analysis on the topic of 1,4 Dioxane in bodycare products, among things.)
I don’t know who or what started all the fuss. There’s some idea that the initial claims were written by a company making a rival chemical to SLS. Or perhaps it’s that SLS is such an effective cleaner even in really greasy jobs, there must be something malignant about it. Or it could have been an understandable mix-up with sodium laureth sulfate, which is indeed linked to carcinogens (see my next blog on the “-eth’s”). Nevertheless, the rumor about its carcinogenic power spread like wildfire over the web, assisted by the general public’s accurate and growing suspicions that bodycare companies were lying to them.
Unfortunately, SLS became the scapegoat for these suspicions, and real culprits slipped by. Huge corporate bodycare companies took full advantage to extract as many dollars as they could out of this paranoia. Soon, the onslaught of “SLS-Free” products hit the shelves in Whole Foods, Wild Oats, and other natural stores. The thing is, many of the other ingredients in these products were petroleum based, and much more harmful to the body and the environment than SLS. However, with this artificial “SLS-Free” distinction, these green-washed products soon became best-sellers even within the super-green community.
That is why the whole SLS panic really bothers me. Aside from the fact that most of it is untrue, it is being exploited by the most unscrupulous companies. Frequently, chemical magazines contain articles about how to replace SLS in bodycare products with petroleum based water softeners. Trust me when I tell you that petroleum based water softeners are worse.
When SLS is not formulated properly, it can be an irritant to the skin. And since I can’t vouch for how it is formulated by each company that uses it, I avoid it across the board in all body care products. It should never show up in certified organic products. However, it appears in almost every conventional toothpaste and shampoo, and even in many that are sold by “natural” brands. Since there are tentative links to causing canker sores in the mouth, as well as acknowledged skin irritation when not balanced properly, I think it’s best to steer clear of it for bodycare. I can do without the bubbles.
So, this blog has gone on long enough. I haven’t addressed the whole SLES and 1,4 Dioxane issue (which is linked to Sodium Laureth Sulfate, among other things, but not Sodium Lauryl Sulfate). I will pick that topic up next time.
Note: My brother Mike Bronner had a hand in writing part of this.

Great article. I just recently rediscovered Dr Bronner’s soaps after many years. While checking out the company website, I found this blog and it is awesome. I’ll point people to it from my blog “Live Well – Live Prosperous – Live Green”. Good stuff here. Thanks for sharing.
I have been avoiding Sals Suds for this very reason. And unfortunately, there’s still a lot that’s unclear.
Environmental Working Group – which does distinguish between lauryl and laureth – considers both to be “moderate hazards.” (Although SLES is one point higher on EWG’s scoring)
http://www.cosmeticdatabase.com/ingredient.php?ingred06=706089
http://www.cosmeticdatabase.com/ingredient.php?ingred06=706110
I have a violent reaction to SLS. Some people do. Nonstop sneezing, burning mouth, body aches, blisters on roof of mouth from breathing powdered carpet cleaner used in office. This chemical can build up in your system after years of exposure. Then BOOM. That’s what happened to me. I’ve never considered my self “one of THOSE allergy people”. Unfortunately, I AM NOW!!! Arrrgh. Trying to find products without SLS,Soy,Gluten or other chemicals is difficult and confusing. SLS goes by many other names too! I use and LOVE Dr. Bonners Castile soap for clothes and body and hair but need makeup and moisturizer. Any suggestions?
My (perhaps imperfect) understanding is that SLS irritates some people’s skin and especially scalp. Sal Suds isn’t intended for anyone’s face or hair.
I check the EWG’s website a lot and I take it seriously, but I don’t accept their ratings as the gospel truth. I’ve seen ingredients labeled “0″ because it wasn’t in their database and citric acid gets a “2/3″.
http://www.cosmeticsdatabase.com/ingredient.php?ingred06=701385
Hi Everyone,
The EWG site is a great starting place. It definitely points people in the right direction. Two things to keep in mind, though. First, it is a site dedicated to body care. So they are evaluating ingredients with that in mind. Any ingredient that produces irritation to the skin is going to get a red flag from them, as it should. SLS should not be in body care products. Secondly, the scope of EWG is limited. When an ingredient is listed, they are evaluating it across the board, not taking into consideration how various companies might use it. They are letting you know that there might be a problem, and you need to look into it further. Hope that helps!
Thanks for writing!
Lisa
While I recognize that SLS should not be in body care products, and that Dr. Bronner’s would never market its Sal Suds for body care, all of the active ingredients in Sal Suds (SLS, Coco-Betaine, Lauryl Glucoside) are the same as in almost every shampoo on the market. However, since Sal Suds doesn’t contain any preservatives, silicones or other nasty stuff, and is formulated in such a way as to not irritate the skin, I must admit that I have used it as shampoo in a pinch (not regularly, of course), and it worked just like a conventional shampoo (e.g., stripping it of all of its natural oils and leaving it squeaky clean). I felt reasonably good about using it since it didn’t contain any of the junky stuff that coats the hair or causes cancer. I still prefer (and recommend) using Dr. Bronner’s castile bar soap as shampoo, but I just thought I would mention this other use for Sal Suds!
hi lisa,
while there is likely no cancer risk from SLS itself, please read this small blurb i just came across on the SEVENTH GENERATION brand website, discussing a change from using SLES in their dishwashing liquid to SLS, in order to protect against carcinogenic byproducts from SLES. after they switched, they found the SLS (from numerous sources) to be contaminated due to processing issues in factories they relied upon. check it out:
_____________________
“For the past two years, we’ve been on a mission to reformulate our hand dishwashing liquid to remove the small amounts of 1,4-dioxane that had been present as a byproduct of a reaction called ethoxylation. Our previous hand dishwashing formula used a surfactant system based on sodium lauryl ether sulfate (SLES), which can be a source of 1,4-dioxane contamination. Even though we made sure the levels of this contaminant were extremely low (less than 5 ppm), we were committed to providing our consumers a product without any 1,4-dioxane, a possible human carcinogen.
Our search led us to a surfactant system based on Sodium Lauryl Sulfate (SLS) which does not cause 1,4-dioxane formation. This switch from SLES, which is a plant-derived surfactant that is modified with petroleum, to the plant-derived SLS increased the renewable carbon content of the dish liquid by 27%. Patting ourselves on the back, we eagerly awaited the test results that would confirm our success. To our dismay, 1,4-dioxane was detected — despite the fact that none of the chemicals associated with it are present in the new formula. Even worse, the levels we were finding with SLS were almost as high as the levels we had found with SLES. We tested just the SLS; we used different suppliers. The results were always the same.
Diving into this further, we discovered that SLS is often formed on the same equipment used to make SLES. If chemical suppliers don’t clean their reactors properly between batches, there can be cross-contamination with 1,4-dioxane.
We took these findings to our own supplier as well as others in the industry interested in addressing this. Fortunately, there are solutions. Suppliers can change their methods of working with SLES to eliminate some of the 1,4-dioxane, and they can employ better production, cleaning, and wash-out procedures to reduce the likelihood of cross-contamination. Now our hand dishwashing liquid tests do not detect any 1,4-dioxane. And we’ve gone way beyond improving the small amount of SLS we purchase every year; the research has the potential to improve all of the SLS used across the entire industry.”
(http://www.seventhgeneration.com/mission/product-philosophy/improved-products-2009)
_______________________
i’m wondering — does DR. BRONNER’S conduct tests to make sure there is no similar contamination issue with the manufacturing/processing/sourcing of SLS for Sal-Suds?
thanks for considering my question. :>) …i really appreciate your willingness to discuss the DR. B’s products with us directly in a public forum; it’s an awesome testament to how amazing your company is (and has been) in its care for consumers.
by the way, i grew up in the late 70s and the 80s, with my family using Dr. B’s from way back then! i still use DR.B products everyday today. i’m SO grateful you guys exist.
thanks again,
=ilais
hi – i just wanted to point out that we have very hard water here and that i have found that sal suds HIGHLY diluted (1 drop in a liter of water!) works great for my hair. When i tried using any of the liquid soap and even the bar soap they dried out my hair even with a vinegar rinse. The sal suds (if very diluted) works great! I am allergic to almost everything and haven’t used SLS shampoo or anything else with SLS for years because I was afraid of it. But after finding sal suds I am amazed to find my clothing finally residue free again after years of trying soap nuts and also home-made laundry soap even with borax added and a vinegar rinse. Now my clothing is actually clean and my hair is shiny!!!
We love sal suds!
Hi, i.just rediscovered dr bronner soap as well. I used it to wash my hair and was amazed that my curls were soft and bouncy with no conditioner, not dry and frizzy like they usually are after I shampoo. I wish I had tried it years ago.
Also, in reply to the post regarding natural moisturizer and makeup…I see it had been two years since your post, but if you are still looking I have completely natural moisturizers and cosmetics. Boost my web page if you like. Sunshinenaturals.biz.
Thanks for a wonderful soap!
Kim
Hey, everyone! Somehow I’ve missed the comments on this post – so I’ll address even the ones from over a year ago!
Sal Suds as Shampoo – I, too, have used Sal Suds as shampoo. Regularly, I use the castile soap, but recently I used way too much coconut oil as a hair mask, and I needed the Sal Suds to get it all out. (I’m still working on the amount to use for a hair mask – I’ll let you know. It won’t be much, that’s for sure!) Afterwards, my hair did look and feel great. If you do compare the ingredients in Sal Suds to conventional shampoos, there is a lot of overlap. Conventional shampoos and Sal Suds are both detergents, and if for some reason my only two options for hair washing were Sal Suds and conventional shampoo, I’d choose the Sal Suds every day.
Hi Ilias – The presence of 1,4 Dioxane in Seventh Generation products was revealed via a third party test of most, if not all supposedly organic and natural products – both body care and house cleaning. Sal Suds was included in that study, as well. Seventh Generation, as well as other popular cleaning brands, turned up positive for 1,4 Dioxane. Sal Suds did not. We also do our own quality control of raw materials and finished products to make sure that what they say they contain is all that they contain – no more, no less.
Here is the original study: http://www.organicconsumers.org/articles/article_10918.cfm
Here is the follow up study a year later: http://www.organicconsumers.org/articles/article_17156.cfm
You can also search the Organic Consumer’s Association (www.organicconsumers.org) for “1,4 Dioxane” to find other studies of available products.
All the best,
Lisa
Good afternoon!
Lisa, thank you so much for this entry. I was having a hard time sorting through all of the information and contradictions with SLS. What you are saying makes sense. Body care vs home care. The new Cleaning Guide is up on the Environmental Working Group’s Web site: http://www.ewg.org/guides/cleaners It’s very interesting, and disappointing. A lot of my “green cleaners” who shall remain nameless were a huge disappointment. I have determined the only “safe” thing to do is use my Dr. Bronner’s for everything! We just need to figure out how to use it in the dishwasher!
Hi Shannon – Yes, a lot of companies have jumped on the green bandwagon, but don’t have a worthwhile product to contribute. They just try to take advantage of the upswing, I guess. That is a very helpful guide from the EWG regarding the safety of products. I wish someone would do a ranking of the effectiveness of products, though. Some sort of Consumer Reports, independent evaluation. Perhaps some day!
I was very interested in their findings on dishwasher products. I’m going to look into them, also.
All the best,
Lisa
Hi Lisa, my newborn has developed severe eczema and I’ve been reading that detergents containing SLS maybe a big contributor. Despite your SLS being derived from plants, I think they all are deemed risky. Have you come across this issue before?
Signed, a desperate new mom
Hi Canem – I absolutely wouldn’t use any product containing SLS on a newborn, or anyone with sensitive skin. It isn’t great for any skin and is classified as a skin irritant. Definitely read those baby product labels, because it is found everywhere, unfortunately. It’s also extremely common in toothpaste and you really have to search hard to find one without it. Two of my kids get cankersores when they use toothpaste with SLS.
Bear in mind, that my point here is that it won’t cause cancer. It still shouldn’t be in bodycare. Hope that helps!
All the best,
Lisa
Thanks Lisa. I meant just as washing machine detergent, not on his skin. For now we are using your soap and vinegar in the rinse cycle and it seems to be working ok. I’m at a loss as to what non detergent product to use in the dishwasher. I’m trying to rid my house of all potential irritants out of desperation.
If you have any non SLS dishwasher fluid solutions please let me know.
Thanks so much,
Canem
This was a very insightful blog – and the comments were even more so.
Unfortunately, I still have to be concerned with any products containing SLS because of the contamination problem. Unless other companies are as upfront and careful with their ingredients as Dr. Bronner’s, their SLS might be contaminated.
I’d be interested in seeing an updated study showing if the 1,4-Dioxane contamination of SLS is still a common problem or if suppliers have cleaned up their act to keep SLS safe. Unfortunately, I assume most of them are still concerned only with profits and cutting corners will continue.
sodium laurel sulfate is very drying to my hair.. no matter if it is used in accordance with other chemicals or not. I prefer to use sulfate free shampoo.Not only because of cancer causing apprehension, but it’s just it’s a drying element
Hi Canem – Sorry about that. Definitely go with the castile soaps for laundry, then. Especially the unscented Baby Mild. I don’t have a good dishwasher formulation yet.
Hi Jeff – I just searched for an updated study (more recent than 2009) and haven’t found one yet. If I do find one, I’ll share it here. You are right to be careful.
Hi stephanie – Yes, I also avoid the sulphates in body care products as well. It is very drying, as you say.
All the best,
Lisa
Thanks for the response Lisa. To add some evidence to this thread, here’s a response I got regarding another company’s (leaving out the name as they are somewhat of a competitor with Dr. Bronner) product which contains SLS:
“Thank you for your e-mail, and for your patience. I heard back from our research team, and they let me know that we have analyzed some of our raw materials for 1,4-dioxane by GC-MS with a detection limit of < 100 ng/g. SLS was not included in the screen due to the fact that the none of the steps in the manufacturing process for our SLS has the possibility for producing any 1,4-dioxane.
We have also tested some of our toothpastes in the "contaminant screen", which is a screen where we look for any kind of unwanted products, not only 1,4-dioxane. This contaminant test uses a technique called SPME-GC/MS (solid phase microextraction – gas chromatography coupled to a mass spectrometer) and identifies compounds by comparison with a MS library.
None of our tested products (including those with SLS as an ingredient) contained 1,4-dioxane."
I informed them of the cross-contamination issues mentioned in the Seventh Generation blurb and suggested they start testing their SLS for that reason alone.
It's good to see that their end products have tested negative for 1,4-Dioxane and is one small bit of evidence that SLS producers may have cleaned that up to some extent.
That makes 3 companies, Dr. Bronner first a foremost, from which I can now safely use products containing SLS! Any other company with an SLS product will need to give me similar confirmation that they test for unwanted chemicals in the raw materials and/or finished product!
I am very sensitive to most SLS. I say most because only Dr Bronner’s Sal Suds don’t cause me to have a negative reaction. I tried the so called non toxic products but the SLS made me feel like my skin was burning. It can take up to a week to for reaction to wear off. Even simple dish washing was brutal for me until I found Sal Suds. It is the only cleaner I will ever use to clean my place.
Hi, when I travel I us e Physiogel Cleanseron my skin. What do you think about it? Thank you.
By far the best product out there! I have asthma ( steroid user) and eczema extremely bad. To top it off I own a cleaning company that deals with people and pets who have extreme allergies. I use nothing but Dr. Bronner’s products in my client’s and my own home. Not only do they clean beyond any other product I have tried, they’re upfront with ingredients and made here in the USA which says a lot. Cruelty free is very important to me and not many companies can make this claim.
Lisa, Your family is going above and beyond what most do these days. For that you will always have my business and that of my clients. Great company, great products keep doing what you’re doing! God Bless for doing the right thing!
I do use salsuds in the dishwasher and for me it’s 1/2 tsp ss to 1 cup baking soda. It all goes in together and my dishes come out sparkling clean! They key is to have hot enough water. (run the hot water in the kitchen sink to drain your water line of cold water)