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 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.

Dr. Bronner's Sal Suds cleaner

I think this article has a good overview of the rumors: This page 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 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.

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

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


  3. 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?


  4. 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.

    • 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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!

  11. 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,

  12. 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 🙂

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