Monday, 11 June 2012

Sulfate free shampoos: genuinely gentle

The last post highlighted olefin sulfonate - an ingredient used in sulfate free shampoos that on its own is just as harsh as SLS.

There are however some surfactants used in sulfate free shampoos which are genuinely gentle (this is with the provision that the shampoo is placed in a pH range of 4-7 which reduces irritancy). This is all to do with the charge of the surfactants.

Good cleansers - negative charge - harsh to skin/hair
In the table, you may have noticed that the surfactants which generally produce some reaction are anionic (meaning they carry an overall negative charge). Surfactants like these are usually more efficient at cleaning hair because they are repelled from the surface of hair (which itself has slight negative charge). However they irritate skin and hair in part because they add to the negative charge but mostly because they are highly efficient when removing oil from the surface of hair and skin.


Sulfate and Sulfate Free Shampoo Surfactants
Surfactant Sulfate Free Charge %Skin Swelling (in 1hr) Irritation Intensity
SLS No Anionic (-) 20-40% Severe in 1 day
Olefin Sulfonates Yes Anionic
(-)
15-26% Severe in 1 day
Soap Yes Anionic
(-)
13-21% Intense by day 4
SLES No Anionic
(-)
11-17% Moderate by day 5
Sorbitol esters (polysorbate/tween 20) Yes Non-ionic
(none)
0.2-0.5% None expected


Why not use positively charged surfactants?
Generally surfactants with a positive charge will not tend to be used in shampoo at all. This is because they have a tendency to build up on the surface of hair instead of cleaning and removing oil. Many positively charged surfactants do also tend to be larger in size and more suited for a hair conditioner rather than a shampoo. So while positively charged surfactants would not irritate skin, they would also not tend to clean well enough

Weaker cleansers - no charge - gentle to skin/hair
The gentlest (in terms of irritation) sulfate free shampoos will have non ionic surfactants. This means the surfactant has no overall charge and therefore does not tend to cause the skin or hair to swell in general. However, some of these surfactants tend to not clean as well as the negatively charged surfactants, which often means that:

1.You will find many surfactants in the bottle as a combination is necessary to make the shampoo more effective.
2. A mix of anionic and non ionic surfactants is used to increase the cleaning power.

Something a little bit special - cocamidopropylbetaine
To help the issue of low cleaning with non ionic surfactants, many sulfate free shampoos contain one specific surfactant - cocamidopropylbetaine (cocobetaine /cocabetaine). This surfactant is special because it is zwitterionic (meaning it has both negative and positive charge). This means in essence it can clean hair a little bit better than non-ionic surfactants due to having a negative charge but at the same time be less irritating than a negatively charged cleanser as it also has a positive charge


Coming up next is a list of surfactants and whether they are anionic, non ionic or zwitterionic (so that you don't have to guess!). I will also have a table of where your shampoo fits in a gentleness index based on the surfactants in it (remember that your own test by using the shampoo is the best test, not just by looking at ingredients).


10 comments:

  1. Hello,

    I use petroleum oild based products as sealants. Is there a non-sulphate shampoo I could use to remove the build-up or is sulphates the only way to go. I normally use the lusters pink shampoo, which seems to work very well and my hair doesn't feel stripped even though it contains SLS.

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    Replies
    1. Sulphate free shampoos tend not to remove oil as well (silicone and mineral oil are considered oils just as much as coconut or olive oil). However, many naturals actually do not want to completely strip hair of oil and in which case sulphate free shampoos therefore work well enough. So it is totally up to you, if you want thoroughly clean hair - go for a shampoo with sles (which is gentler than sls) . If you do not really want your hair to be super clean (i.e oil free) - a sulphate free shampoo is a better choice.

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    2. Sorry to rain on your parade but this is not true if the lady above were to use mineral oil only rather than petroleum or products that contain combination. The information I am sharing is not my own. It comes from Ktani Hair Sense Blog and it is not opinion...it is fact. Mineral oil itself, purchased as a laxative or as baby oil, washes out of hair very easily, so much that even certain cleansing conditioners can remove it. Cocamidopropyl betaine is a great cleanser for curly hair which is found in Curls Cream Cleanser. In order to br successful with any product, including mineral oil, long term, you have to realize that anything added to a cleanser can cause build up. So initially when I firsr started using mineral oil my hair was practically perfect...then when I reintroduced conditioners to give me more slip so that I could comb my hair and not exclusively finger detangle, I started to see split ends again.

      I also saw dry hair as I used harsher cleansers. So I did my research and found that I could be successful if I rotated my cleansers on a schedule going from mild, to slightly strong to harsh and of course the harsh one is a once a month thing (maybe twice). You would actually run into this issue more with other oils before you would with mineral oil. The reason is that mineral oil washes out easily and seals in 99 per cent moisture where as other oils require constant application just to provide all of 20 per cent moisture, plus they are tougher to remove. Again I learned this all from Ktani...she consults by email. So if you use mineral oil alone with a few cleansers that ypu rotate, you can experienced more moisturized hair plus finger detangling...for me it is the besr way to go. The reason I regressed into combing was due to increase in fairy knots. But I am finding ways to get around that without using a comb as much. My hair is fine and combing causes breakage and splits for ne no matter how gentle I am.

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  2. Hi Jc

    I use sulphate and sulfate free shampoos.I am experimenting with sulfate and free sulfate shampoos as well. For a sulfate free shampoo,I use a Shea Moisture Product named - "Organic Raw Shea Butter Moisture Retention Shampoo". I like the shampoo. It's okay. I like the way the shampoo makes my hair feels. Soft and clean. However, 24hrs later my scalp itches a little. Same situation happens when I use a sulfate shampoo. Mild scalp itch. I am not sure why. After a shampoo, I use a wash out conditioner than leave in conditioners.
    I just want to state that I understand that some sulfate shampoos can cause the hair to get very dry or scalp irritation, but I can use a sulfate shampoo and regain moisture back to my hair when I use certain leave in conditioners. It is great that consumers have a choice to choose sulfate from free sulfate shampoos, but if I wanted to use a sulfate shampoo only, I can still maintain moisture to my hair.I have came across some information that the cause of hair breakage might be caused by using sulfate shampoos regularly, and that the only time to use a sulfate shampoo is once a month such as a clarifying shampoo to to get rid of hair product build up. Based on my experience with my hair sulfate or free sulfate, my scalp still mildly itches a little, Also, I have no problem with unusual hair breakage, due to dryness from a sulfate shampoo because a leave in conditioner will moisturize my hair. Well, anyway that is what I am experiencing with sulfate or sulfate free shampoos. You have some very good information based on your research on your Site Jc. I appreciate what you do.

    ReplyDelete
    Replies
    1. Thanks for your comment. The reason for scalp itch is because oil is removed while cleaning hair especially with a surfactant (of any kind sls, sls free or soap). This oil removal makes the skin temporarily drier but you are correct that things like using a conditioner afterwards help to fix this. After a short time, the natural amount of oil (sebum) is restored and the itch goes away.

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  3. Hello JC,

    If you use shampoos with decyl polyglucose or with cocobetaine as sole surfactant (The only surfactant in the shampoo), will they be able to remove Polyquaternium 10,Polyquaternium 80 easily ?

    I heard that the Polyquaternium's are water-soluble, does it means that they don't build up on hair easily ? I also heard some say that they build up easily, could you help me with this please ?

    Thanks

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  4. Jc,

    You are my hair science hero!!! WERK :-)

    Ms.Amena

    ReplyDelete
  5. I would like to know if decyl glucoside is harsh. =( there's a brand of shampoo named Bioland here that contains just that as a cle

    ReplyDelete
    Replies
    1. If the shampoo is pH'd to around 5-7 generally the decyl glucoside is not that harsh (also should have some conditioning agents in the shampoo). If the shampoo is a soap then it will be around pH 11 and then it will have potential to irritate some people (some people do prefer soap though!).

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  6. I usually start to get an itchy scalp 2-3 days after a shampoo, but shampooing is the only way to get rid of my itchy scalp at the end of the week. Is it safe to say harsh shampoos aren't the source of irritation? And if the problem is dry scalp shouldn't shampoo make it worse?

    BTW I love your blog for its scientific approach to natural hair care.

    ReplyDelete

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