There is no cancer risk from SLS (Sodium Lauryl Sulfate)

I 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 body care, 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 body care 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. It is written by Ed Friedlander, a pathologist from the Kansas City University of Medicine and Biosciences. 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 body care companies were lying to them.

Unfortunately, SLS became the scapegoat for these suspicions, and real culprits slipped by. Huge corporate body care 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 body care 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 body care. 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.

121 thoughts on “There is no cancer risk from SLS (Sodium Lauryl Sulfate)

  1. Hi Lisa, Just ordered my first bottle of Sal Suds. Any advice on whether I can use a few drops in my dishwasher?

    • Hi Lucy- Sal Suds does an excellent job of hand washing dishes, but I don’t recommend it for the dishwasher. It is so bubbly that it can seep out of the seals on the door. The Environmental Working Group ( ranks products by ingredients, environmental impact and such. It’s a great resource for finding “greener” products. For your shiny new purchase, be sure to check out the Sal Suds Cheat at

  2. Thank you, Lisa, for so patiently answering the same questions over and over about SLS and Sal Suds.
    I personally love Sal Suds for cleaning. I keep a spray bottle of diluted solution (following the recommendations on the Sal Suds dilution cheat sheet) by the sink for cleaning countertops, etc. I also keep a separate spray bottle of diluted dish soap by the sink for tackling dishes. Sometimes I just spray dishes and let them sit if I can’t get to washing them immediately. I trust Sal Suds to provide some antibacterial benefit. (I feed my dog raw meat, so I have to be careful about hygiene.)
    I’ve also used a diluted Sal Suds solution for mopping and other chores. I wouldn’t be without it!

  3. Hi Lisa, I just wanted to say thank you so much for answering my question about Coco Betaine and Cocamidopropyl Betaine back in April. Besides the Sal Suds I’ve seen Coco Betaine in all sorts of natural shampoos and body washes and just needed to verify it was safe. You’ve cleared up my confusion and I’ll probably try the Sal Suds soon 🙂
    Ps Sorry for the late reply, thought I bookmarked this page but apparently I didn’t!

    Thanks again

    • Hi Erin- You are very welcome! Glad the information was helpful!

  4. Hello Lisa!
    As a new member of the Dr. Bronner consumer family and a very skeptical shopper, I’m excited about the ability to have our concerns addressed personally. I have been using the All One soaps for about 6 months now, having a long illness has made me extremely conscious about what I put in/on my body. I started with the Lavender, then the Peppermint and then the Almond. I’m really excited that I can use these soaps to clean everything in my home. Thank you for the chemistry lesson on sodium lauryl sulfate vs sodium laureth sulfate. As a newly certified aromatherapist, one of the areas of our studies included a strict understanding of chemo-types and variations in plant components (heavy chemistry). It has increased my ability to distinguish and discern much of the hype in all natural advertising when it comes to personal care and home care products. I appreciate the credibility you have obviously earned over the years. Thank you for a great product.

    • Hi Angela- It’s always great to hear from someone who appreciates reading about chemistry, as I do enjoy writing about it. Welcome to the family!

  5. Hi Lisa, thank you for this article and continueing to answer follow up questions/concerns. I knew SLS and SLES were different but everywhere online you basically hear that all sulfates are bad/toxic. Like everyone hear knows it’s so difficult to know who to trust! Trying to be healthier and ‘toxic free’ is how I discovered Dr. Bronner’s products; I have only used the Peppermint Castile Soap so far but am considering the Sal Suds as well. I do have a question though:

    You mentioned a few times on here that Sal Suds contains “coco-betaine” . That is another ingredient i’m confused about. Everywhere online “coco-betaine’ is said to be shorthand for “cocamidopropyl betaine” which according to the EWG has impurtiy and enviornmental concerns.

    I did find this blog/article supposedly by a chemsit that explains coco-betaine and cocomidopropyl betaine are ineed 2 seperate ingredients with different chemical structures and “cas” numbers, though I had trouble using the CAS lookup site they mentioned.

    I’d really appeciate if you can clarify if they are 2 different ingredients and if so which one is actually used in Sal Suds? If it is cocomidoproly bentaine I’m not overly concered as I trust Dr. Bronner’s products to be free of impurties, however I am a little concerned about the possiblty of the ingredient being an “enviornmental toxin” according to the EWG. I know to take them with a grain of salt but still am a bit confused so any clarification would be much appreciated!

    • Hi Erin- It’s great that you read labels and research ingredients! Coco Betaine and Cocamidopropyl Betaine are not the same ingredient. It is very often repeated online that Coco Betaine is merely a lazy person’s way of writing Cocoamidopropyl Betaine, but this is not the case. Cocoamidopropyl betaine is the problematic one, partially because the “amidopropyl” component indicates a compound in the middle in between the coco (from coconut) and the betaine (a nature-identical synthetic so named because it was first discovered in sugar beets). Coco Betaine is made using fairly simple chemistry and biodegrades very readily in the environment. Coco Betaine is a surfactant (cleaning agent) which boosts the foaming properties, as well as the mildness, of the Sal Suds. EWG ranks Coco Betaine (and Sal Suds) as a 1, its lowest/safest rank. Also, because Sal Suds is so concentrated, it is highly diluted when used as directed. If you still have concerns about Sal Suds, try our Castile soaps for household cleaning.

  6. Is Sal Suds safe for a vinyl luxury flooring? I know traditional cleaning products are too harsh and can dull the surface, leave soap residue, and lift the glue that adheres the vinyl to the floor.

  7. Hi Lisa,
    I am wondering about SLS and it being a synthetic ingredient. I thought synthetic ingredients were not good for your body or in a cleaning product. Can you explain. Thank you for providing good information about your products.

    • Hi Suzanne- It’s great to hear you pay attention to ingredients. Not everything synthetic is bad, in the way that not everything natural is good. The biggest risk from SLS is that for some people, it is a skin irritant because it can be so drying. SLS is so good at picking up oils that it pulls them right out of our skin. We countered this tendency by balancing it with Coco-Betaine. The Cosmetic Safety Database ( gives SLS a safety rating of 1-2, indicating that it is of very low risk. Studies have consistently shown that it is safe to use in low concentrations and in products that are meant to be rinsed off – both of which are true of Sal Suds. If you still have concerns, our Castile soaps, which do not contain SLS, can be used for both personal and household use.

  8. ? If I wash my floors, both wooden and other surfaces, with Sal suds,. is it safe for my cat? Considering she walks everywhere, including just mopped floors and is constantly grooming herself and licking her paws? Thank you?

    • Hi Ronni – I haven’t had a problem using Sal Suds or any of the scented Castile soaps when cleaning at home. Our soaps have a small concentration of essential oils, which is further diluted when used in cleaning, and then wiped off. But if you have any concerns, the Unscented Castile soap can be used for cleaning.

  9. Hi, I’ve also sent a message via the contact page before I saw this page that is directly for SALSUDS. After researching Sodium Laurel Sulfate, I found the following link to be concerning as it mentions “The substance is toxic to aquatic organisms. It is strongly advised not to let the chemical enter into the environment. ” as well as “Routes of exposure
    The substance can be absorbed into the body through the skin and by ingestion.

    Effects of short-term exposure
    The substance is irritating to the eyes, skin and respiratory tract. ”. Here is the link
    Granted this is from April 2008, however my concern is the rinse off is going down the drain and how it can be effecting the environment.

    If you can send me articles or links that will prove this incorrect it will be much appreciated.

    Thank you!

    • Hi Mary Beth – Thank you for reading labels and being conscientious with the products you use. As a company, Dr. Bronner’s is committed to environmental responsibility and sustainability. As one measure of this, many of our soap products, including Sal Suds, our household cleaner, have been tested for highest level of biodegradability by Eurofins, one of the world’s top-ranking environmental labs. The Environmental Working Groups (EWG) rates SLS as hazard score of “one” – that rank indicating very low toxicity to health and the environment ( You may also find this SLS research helpful: The SLS is diluted in the Sal Suds formula, and because Sal Suds is two times more concentrated than traditional detergents, it should always be highly diluted for use (about 1 ½ tsp. per gallon depending on use). I would consider Sal Suds a better alternative to many conventional cleaners. The EWG gives Sal Suds a hazard score of “one” ( SLS can be irritating to skin, which is why it should be avoided in personal care products. Our Castile soap products, which do not contain SLS, are a great alternative to Sal Suds. Castile soap can be used for personal care and household cleaning. See my blog post with its uses and dilutions.

  10. RE: “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.”

    Dr. Mercola disagrees:

    “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,16 at least one study linked SLS to nitrate absorption. The Greenfeet article states:

    ‘A study cited 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.”

    • Hi Tammi – Good on you for reading up and educating yourself on personal care products and ingredients. This particular article raises the issue on lack of oversight in cosmetics and highlights the prevalence of toxins and other carcinogens in cosmetics. Unfortunately, the article stumbles upon the common confusion between two different ingredients, SLS (sodium lauryl sulfate) and SLES (sodium laureth sulfate). You see this repeatedly throughout the article when it says “SLS/SLES”, as though they are the same thing. These two are not. SLES has gone through an additional process called ethoxylation SLS does not go through this process. The article indicates a lack of understanding about this distinction, as seen here, “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,5 which will be discussed in more detail later.” While it is very true that ethoxylation creates 1,4 Dioxane, it is not true that SLS is ethoxylated. Only SLES is. The article also mistakenly warns that mixing SLS with Triethanolamine (TEA) creates nitrosamines. The SLS has no part in the creation of nitrosamines. The TEA – as well as its close cousins Monoethanolamine (MEA) and Diethanolamine (DEA) – is the culprit. TEA/DEA/MEA contain an amino group (as seen in the ending “amine”) and when they get ahold of nitrogen, you get a nitrosamine. However, SLS does not contain a nitrogen atom. Because TEA, DEA, and MEA so readily create those carcinogenic nitrosamines, it is very important to avoid them in all body care. Again it is not the combination of SLS and TEA that is the problem, but the TEA that is the problem.
      All that being said, I absolutely agree that SLS should not be in body care products because it is an irritant to skin and mucous membranes. It’s up to us as consumers to continue doing our research, read labels and not buy personal care products containing SLS.

  11. In looking at better products to use on our bodies, I recently came across an article that says SLS is being replaced with Sodium Coco Sulfate and called safer/less drying, but that it is basically the same thing. Have you looked into this? Thank you!

    • Hi Toni – Yes, and it feels very much like a marketing maneuver that manufacturers are using to make the claim their product is “SLS-free.” Sodium Coco Sulfate is an almost identical ingredient to SLS and as such, it can still be drying and irritating to some. For this reason, it’s a good idea to avoid it in your personal care products.

  12. Sorry, I do have some concerns on SLS that’s in the Sal Suds. Have been reading the thread and some other articles that others have brought up. Just bought a bottle of Sal Suds, was planning to use it for dishes as suggested in the Sal Suds cheat sheet. What’s the bottom line? Is the SLS in Sal Suds safe for dish soap? Understand that it’s not suppose to be for body. But if it is ‘bad’, isn’t it not so good for washing dishes too? As we may be eating the residuals of the SLS, directly, which is worse.. right? Or doesn’t this come down to, To Each Its Own? TIA!

    • Hi Ivy- Sorry to not see your question sooner. The SLS in Sal Suds is completely safe for washing your dishes and just about any other nook and cranny of your house as well. As I covered in the article, the cancer concern is completely unfounded, as verified by the Environmental Working Group, International Agency Research on Cancer and the American Cancer Society. The biggest risk from SLS is that for some people, it is a skin irritant because it can be so drying. SLS is so good at picking up oils that it pulls them right out of our skin. We countered this tendency by balancing it with Coco-Betaine. If you are still concerned, our Castile soaps contain no SLS and can be used in place of Sal Suds. You can find the Castile soap dilutions cheat sheet here:

  13. I’ve been reading this blog for quite some time but this is my first comment! So I must begin with a huge THANK YOU to Lisa Bronner for sharing all this valuable information! I hate the mainstream marketing of toxic products, but also the fear-mongering/green-washing out there…Dr. Bronner’s is the voice of truth and logic!!!!!

    So now to my question. I’ve used conventional shampoos and body washes with SLS for years and they work just fine for me. Would this mean that I could use Sal Suds in the shower for similar results? I have hard water so I don’t like to use soap in the shower in order to avoid soap scum.

    • Thank you for the reply! A couple months ago I switched to more natural housecleaning methods – the only ingredients I now use (not all together) are Sal Suds, vodka, vinegar, baking soda, and essential oils – and I’m absolutely in love with the results!
      Now I’m working on converting my personal care products, so I will take your advice and try Castile soap as my shampoo & body wash (with ACV rinse). Fingers crossed that it works as well as I hope! It feels so good to rid my life of toxic, synthetic, unnecessary ingredients 🙂

  14. I notice somewhere you advocate the use of microfiber cleaning cloths, which are often touted for their cleaning properties even with plain water. However, these cloths shed fibers, particularly when they themselves are washed, that do not biodegrade and are contributing to water pollution. Old-fashioned cotton cloths are much better.

    • Hi Anne – Thank you for alerting me to this issue. I am looking into it and will definitely circle back around with what to do next. Since it looks like the primary source of the pollution is through their washing, I’ll check out this Guppy Friend washing bag that has been developed for washing synthetic fabrics and catching shed fibers. Cotton does work well for cleaning but is also one of the most pesticide thirsty and genetically engineered conventional crops. An organic source for that would be key as well. There is always so much to keep on top of with these daily decisions we must make.

    • Absolutely true about the pesticides! As you said, there just isn’t a simple answer,

  15. Thank you for breaking SLS down! I just wanted to add one thing… While SLS isn’t a carcinogen, it is an irritant, toxic to aquatic life, and used in some pesticides:

    I still use Sal’s Suds for my down and dirty household cleaning but I won’t wash my dishes with it or use it for my laundry. I don’t like the idea of flushing any amount of this down my drain regularly. Unfortunately these days we have to account for more than just ourselves when we think about our household products and no one makes it easy.

    Thanks for the super informative post!

    • Hi Leah – It’s great that you look so closely at the ingredients you bring in to your house. Everyone should be doing that. I totally understand your concern with SLS, and our Castile soaps can do pretty much everything you might otherwise use Sal Suds for (just not for car washing). The issue of SLS being an irritant is the prime reason why it should not be in personal care products. It irritates because it is very drying. It is very drying because it readily grabs hold of passing oil molecules. This is what makes it a great cleaner, but we don’t want to lose that many oil molecules in our skin. While we don’t notice it as much on the tougher skin of our hands, it is particularly drying on more sensitive skin, such as our face and mouth, which makes it crazy that it is so very common in shampoos (which run on to our face) and toothpaste (with some correlation to canker sores). It is this dehydrating effect that has caused one company to get approval for its use as a pesticide – a maker of a pet shampoo to kill fleas and ticks called “Dr. Dogkatz Critter Chaser”. The odd thing is, although we will never seek EPA recognition for this as a pesticide, Castile soap also happens to kill fleas and ticks, as well as other insects. Here’s the EPA info The toxicity to aquatic life is when at unnaturally high concentrations that would never happen in normal usage and is counteracted by SLS’s exceedingly fast biodegradability. SLS breaks down so quickly in our drains long before it would reach aquatic life. We have biodegradibility certificates on the Sal Suds that I am happy to email out to whomever would like to see them. Email me at

      Keep up your research and let me know if I can answer further questions!

  16. I appreciate all your efforts in educating about these ingredients. I am new to all this and truly my head is spinning from all the research and differences in opinion – many of which could be based on false data. Your thorough explanations for this ingredient helps my decision making… and helps my head spinning slow down.

  17. Interesting discussion, but I don’t really understand the overweening concerns, considering the miniscule amount of the product used in the cleaning recipes, compared to the copius amounts of water.

  18. Am I too late to this dogfight?

    I could conduct research on endless ingredients in all the products I consume. Sorry, don’t have the time. Yes, I am interested but at a certain point, I either trust or distrust the product’s maker. And if it has Dr. Bronner’s stamp of approval (after copious research, I am sure), I will accept it’s safe.

    • Thank you, Terrance. We value our customers’ trust very highly.

  19. Your Sal Suds comes into contact with our hands so, while you do not use it in your body products, it still gets rubbed into the body during normal use. I suppose you want us to wear gloves, but I prefer a more natural product that does not require body shields during usage. Why not just change to a more benign suds-producing ingredient, as other natural products have already done?

    • Hi Janice – Thank you for sharing your concern. We don’t necessarily recommend using gloves with the Sal Suds unless it is drying out your hands. Sodium Lauryl Sulfate really is one of the most benign synthetic ingredients available. The Cosmetics Safety Database gives it a 1-2 in their hazard rankings (, which is almost the lowest (i.e. least hazardous) ranking they have. SLS has been super targeted by false marketing. It’s only drawback is that it can be drying to skin, which is why it shouldn’t be in personal care products. There is no other risk of harm to our bodies from it. All that being said, it is a synthetic ingredient, which is why any product that contains it is actually a detergent, as is our Sal Suds. If you’re looking for a natural product, the Dr. Bronner’s Castile Soap is made entirely from pure plant oils.

  20. Lisa, I’m so happy that I found your website! I’ve used Dr. Bronner’s products for decades. To be honest, I trust these products so much that I don’t even look at the ingredients. Thank you for clearing up the discrepancy between sodium LAUREL sulfate (the good ingredient) and sodium LAURETH sulfate (the bad ingredient). I would never realized there was a difference. I color my hair, and I heard that sodium laurel sulfate would be a no-no on color-treated hair; thus, I’ve bought SLS-free shampoos and conditioners. Maybe I can go back to other products that I really like, if it’s okay that they’re made with sodium laurel sulfate.

    • Hi Jan – I apologize that I didn’t see you comment earlier. The only issue with SLS in personal care products is that it can be drying.

    • Hi Diana – I apologize for not seeing your comment from March earlier. I appreciate your in depth look into this issue. The Dr. Mercola article continues to lump together SLS and SLES, which though related have significant differences. (From the article – “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”) SLES is the only one of the two that undergoes ethoxylation, which is the process that produces the carcinogenic byproduct 1,4 Dioxane. SLS does not contain a nitrosamine group and therefore cannot have the carcinogenic concern. Another error in the article is the reference to the rating given to SLS by the Skin Deep database. SLS earns a 1-2 hazard score, almost the lowest possible hazard. (See SLES is the one that gets the moderate hazard score (

      I know this is enough chemistry to make the head spin, but I hope this helps clear up some of your concerns.

  21. Time for true confessions, folks. It is February 9, 2017, and I have missed several months of comments for the simple reasons that things went a little crazy around here. I very much apologize. I am tackling them now for the sake of those faithful and new readers who might actually read them all. I am going to start with the most recent. Bear with me.

  22. Hi Lisa,

    Why si Sal’s Suds so hard to find? has a few bottles fut want 46 – 98/ for 16 and 32 oz sizes. Even Dr. Bronners’s site is out of stock. When will it be available?



  24. Hi Lisa, when you say “half cup”, may I know what is the actual amount? Thanks!

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