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Stearamidopropyl Dimethylamine and Behentrimonium Methosulfate
I am looking for some advice or anecdotal info on the use of these two and possibly also Centrimonium Chloride as well.
First of all in a small amount in a shampoo formulation to give a slight conditioning effect in the place of something like polyquaternium 10 or 7, and also in a conditioner for the same reason. I have read that these cationic surfactants don’t build up like polymers do, does anybody have any experience with this?
Would i also be correct in saying that Stearamidopropyl Dimethylamine neutralised with a weak acid such as citric is the only one i could use in a shampoo and still be compatible with anionic surfactants?
Perhaps Stearamidopropyl Dimethylamine for the shampoo and Behentrimonium Methosulfate for the conditioner? What does everybody think?
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6 Replies
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These are cationic surfactants. They will not work in anionic shampoos. Cationic will complex with anionic to produce a salt. You will not get any conditioning effect from them. Polyquaternium is a cationic polymer which will not form the same kind of structures with anionic surfactants. That’s why it can be used in a shampoo whereas cationic surfactants cannot.
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Hi @Perry, I might be wrong but it looks like Stearamidopropyl Dimethylamine is an exception. I saw it in products with anionic surfactants (a couple of examples below)
https://incidecoder.com/products/glenmark-bontress-hair-revitalising-shampoo
and some suppliers suggest it can be used in shampoos https://cosmetics.specialchem.com/product/i-evonik-tego-amid-s-18
Also, I am not sure if
Stearamidopropyl Dimethylamine and Isostearamidopropyl Dimethylamine is the same thing but this is a formula from Harry’s 8th edition (p 629)
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@ngarayeva001 - Being able to produce a stable formula and one that provides a benefit are two different things. Despite what incidecoder or even Harry’s says, in my opinion these ingredients will not provide much benefit when delivered from a shampoo. I believe the ingredients listed in the formulas you linked are performing the function of being opacifying agents & foam reducers. They are not conditioning hair.
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@Perry @ngarayeva001
thanks for the clarification, i thought this may have possibly been the case. Might have to just stick with Polyquaternium 10 or 7, I keep getting conflicting info of which of these is less likely to build up, what is your opinion?Also what about the use of Steramidopropyl Dimethylamine and Behentrimonium Methosulfate in a conditioner? They seem to be touted often as the new wave on conditioners and i’m just wondering if it’s all hype or if theres and legitimacy to the claims.
Perhaps if i use the polyquat in the shampoo then i could just use these in the conditioner?
Cheers
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These two are ‘hyped’ because of biodegradability and being based mostly on renewable resources.Stearamidopropyl dimethylamine and the isostearate version (lower melting point) are not quaternary ammonium compounds and are not necessarily cationic surfactants, they only become such at low pH. This allows for a certain flexibility regarding combinations.Also, the incompatibility of QAC with anionic surfactants isn’t always visible if the ratio of one to the other is kept at >10 (or <1/10) but that’s just a rule of thumbs. -
@qwerty - Stearamidopropyl Dimethylamine (SADMA) works well in a conditioner as does Behentrimonium Methosulfate. They aren’t “new” technology as I was using SADMA in the mid-1990’s in our Tresemme Conditioner. But they are relatively newly in favor as compared to other standard conditioning ingredients like Cetrimonium Chloride or Stearalkonium Chloride.
Yes, using Polyquats in the shampoo and the cationic (or amphoteric) surfactants in conditioners is a good strategy. Polyquat 10 was the first one that was widely used and it is the one that is more associated with build-up. But it’s hard to quantify these things.
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