The Natural Haven : On Sulfates in Shampoo

I am putting forward a few summary science related posts on key topics that are frequently asked about especially by readers new to the blog. I am kicking off with sulfates (or sulphates if you write the Queen's English) in shampoos:

Q. Do sulfate shampoos break hair?
A: Yes but then again so does water, combing, sunlight......pretty much everything except living in a dark room and never touching your hair. (Read more: See how much hair breaks when shaken in water or different sulfate shampoos)

Q: Are all sulfate shampoos harsh?
A: No, some sulfate shampoos can be very harsh, especially those that contain surfactants such as SLS (sodium lauryl sulfate) and ALS (Ammonium lauryl sulfate). Shampoos labelled as clarifying are often quite harsh to skin. Some sulfate shampoos contain surfactants that are considered quite gentle for example SLES (sodium lauryl ether sulfate) which is a modified version of SLS.

Q: What is a surfactant?
A: You must have missed the masterclass from several years back - catch up here!

Q: Why are sulfate shampoos harsh? 
A: It is not just sulfate shampoos that are harsh, non sulfate ones can equally be harsh. Shampoos feel harsh because they strip hair and skin (i.e scalp) of  oil and this causes the skin to retain less water, feel dry and itchy. The better a shampoo is at cleaning oil, the harsher it will feel. (Read more: Why are shampoos harsh)

Q: Do sulfate shampoos have a high pH?
A: In general no, most commercial sulfate shampoos are in the pH range 5-7 (Read more: Comprehensive list of pH values of shampoo)

Q: Should I therefore be concerned if my shampoo feels like it is stripping my hair?
A: Yes you should be unless it is your intent to rid your hair of build up or excessive product in which case a good clarifiying product is necessary. Ordinary use shampoos contain other ingredients to help make them less irritating to skin and you should aim to use a shampoo that is gentle to your hair and skin.

Q: Do sulfates in shampoos cause cancer?
A: No, there is currently no evidence to show that they do. The most effective surfactant SLS is often wrongly associated with cancer but there is nothing in its production process that would result in a known carcinogen. However, its gentle version SLES is produced through a process known as ethoxylation which gives off  a by product that is marked as a possible carcinogen - 1,4 dioxane. SLES is still considered safe as the dioxane produced readily evaporates into air.  (Read more - myth sls causes cancer)

Q: Do you think sulfates should be avoided?
A: I think that people need to make their own decisions and learn to read ingredient labels. In my personal case, I know that from testing, my scalp and skin prefers SLES as a surfactant for normal washing and really dislikes a different sulfate surfactant - ALS. I have tried two sulfate free shampoos and I found them expensive and wasteful because I required a lot of the product to get my scalp clean. Other people like sulfate free shampoos, some people totally avoid shampoo, some people avoid SLES, ALES etc because of cancer concerns.........make your own decision to suit what your scalp and mind prefer.



  1. I am currently using the Jason SLS free jojoba shampoo. I feel it leaves my hair squeaky clean, which isn't suppose to happen with a sulphate free shampoo. But my hair feels soft afterwards. I can't avoid shampoos altogether like many naturals do because I use different styling products with heavy oils and butters at the same time (i.e. hair gel, leave-in, oil, e.t.c). So they need to be removed from the cuticle by shampooing to allow moisture from whatever product to go into the cortex. At least that's how I see it :)

    1. I do agree with you, you have to remove or atleast reduce deposits on the surface of hair in order for conditioner to work effeectively.

  2. The only time i use SLS or ALS is when i am clarifying my hair after using silicones.I only use silicones in the form of a heat protectant when i am doing a length check.
    I haven't completly shunned SLS but i understand HOW they work thanks to your handy diagrams and helpful articles so i know when to use them. :)
    In between clarifying, my hair&scalp is happy with co-washing or shampoos that have mild surfactancts. :)

  3. Hi JC! As a fellow scientist, I love your blog. Will you be doing a post on surfactants that are not "sulfates" per se, but are just as harsh (if not harsher)? I ask because many shampoos advertise as "sulfate-free" but they contain surfactants such as c14-16 olefin sulfonate, which can be just as harmful. Many naturals use these shampoos feeling that they must be more gentle because they are sulfate-free, but that is not necessarily the case. Two brands that come to mind that are loved by anti-sulfate folks are Kinky-Curly Come Clean and the Giovanni shampoos.

    Thanks for all the research you do!

  4. I agree with Anonynmous about articles regarding the SLS free surfactants like cocamidopropyl betaine,Lauryl betaine and the rest as they are in most popular brands.

    In fact what i will say is brands love boasting about SLS free but that diverts you from what ELSE is in it.

    By principle ,I always select my products by checking the ingredients but i made the error of buying a shampoo that had ALS and couldn't believe it as i am quite thorough normally...:-/
    I didn't mind too much but because the site promised it was SLS free that distracted me a bit. So it goes to show that it's worth doing a double take before buying stuff.

  5. i prefer to avoid sulphates except for clarifying because i hate feeling my hair so stripped. i have found a very affordable shampoo elasta qp creme conditioning, and it cleanse great and my hair never feels stripped but moisturised and it also lathers like a sulphate shampoo.

  6. According to my hairdresser, the main concern for sulphates is for color-treated hair. She was telling me that sulphates are used as effective stain removers in laundry detergent.

    1. If sulphates are used as stain removers why would you want to regularly use them in your hair? Sulphates are stripping and that includes stripping the natural oils your hair needs.

    2. It is true that SLS is an effective detergent. However if you took a shampoo and tried to remove a stain with it it really would not work. Many women often get pillow stains from oils, again shampoo does not work on this but a laundry detergent will. The sulphates in shampoo are much much gentler than in a washing liquid or laundry detergent. Shampoos will also have oils such as silicone added to them to further reduce their harshness. A sulphate such as SLES is usually added too and this is really a very gentle cleanser, quite similar to cocobetaine.

      There is real science going into well made products. If you find a shampoo stripping, it does not mean all shampoos are stripping.

      The role of shampoo IS to strip hair of oil because the oil attracts dirt. Your conditioner replenishes this oil along with you taking the steps to add oil to your hair


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