Mildness comparison of two Shampoo formula

Formula a) 
CAPB %6 active surfactant 
Decyl glucoside %3 active 
SLES % 3 active 

Formula b) 
SLES %7 active 
CAPB %1.5 active 
Decyl glucoside %1.5 active 
Cocamide DEA %5 

The rest is the same 

In these two, formula B has better foam, cleaning and is very milder specially to eye compared to formula A. What would be the cause? 

Is CAPB more irritating to eye than these other surfactants? 

As CAPB has it's own preservative ( our supplier don't know what preservative it is), can that preservative be the cause? 

Or something else



  • This is a guess, but Cocamidopropyl betaine has few contaminants, like DMAPA and aminoamine. Both are suspected sensitizers (especially amidoamine). Decyl glucoside as well is not as mild as coco-glucoside.

    What you did in formula b is better in terms of mixing few surfactants in low doses rather than using only one or two.    
  • PerryPerry Administrator, Professional Chemist
    According to the CIR report (see table 6), Decyl glucoside was not-irritating at 1% (pH 7) but was slightly irritating at 3%. So, it could be that.
  • @Perry i couldn't open this cir table. 
    Decyl glucoside may be the cause, I don't like it either but in new formula we are just using a small amount because of glyceryl oleate. 
  • @ketchito that was informative. I thought CAPB and APG would be milder than SLES but it looks they aren't.

    Which APG is mildest in your opinion? 
  • Abdullah Don't get me wrong, LESS is also able to irritate the skin (I used solutions of LESS in the lab to denature some proteins in the past). What you need to do is reduce its charge density, and you do that by mixing it for instance with CAPB. As I mentioned before, the best way to get a mild system is to mix some surfactants that interact with each other (like LESS and CAPB), and at lower doses of each than if you were to use only one or two of them. 
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