lactic acid in a solid shampoo to acidify the ph

I have seen a commercial solid shampoo with this INCI: Sodium cocoyl isethionate, sodium coco-sulfate, stearic acid, disodium sulfosuccinate, stearic acid, theobroma cacao (cocoa) butter, cocos nucifera (coconut) oil, glycerine, cetearyl alcohol, lime (Citrus aurantifolia), rosemary (Rosmarinus officinalis) & sweet orange (Citrus sinensis) essential oils, juniper (Juniperus communis) extract, mica, lactic acid.
The main ingredient is SCI, but I have read ( I can´t remember where) that adding lactic acid to it could make the sci react, lowering its cleaning power. Is that true? What do you think about this formula? Do you think it is well constructed? Thank you.


  • The lactic acid is a very minor part of the LOI. I don't think it would make any difference to the performance or to the pH.

    Regarding the formulation itself:
    How much demand is there for a solid shampoo?
    Assuming this is presented as a solid bar (not a powder) what about the slush factor - that is how easily does product soften and disintegrate (turn to slush) when stored in damp conditions such as a soap dish?
    If it is a powder, what about the sternutatory effects - sneeze causing effects sodium lauryl sulfate/sodium cocosulfate show this very strongly.
    What is disodium sulfosuccinate? I think it should read disodium laureth sulfosuccinate.
  • edited May 2017
    Now the demand is rather high, solid shampoo bars are a trend. They are one of the best selling products in "Lush". I don´t know if you know the brand, but it´s a very popular so called "natural" brand . But when you look to their ingredients, they are not so natural.... I think they have forget to write the "laureth"  in the label (which is such a bad thing...). About the slush factor, the shampoos come with some instructions and tell the consumers to take the bar out of the shower and let it dry after use it. Despite of that disadvantage, people seem to be raving about this solid shampoo bars. Don´t ask me why, because I find them quite unpractical. Anyway. Does a acidic ph affect the SCI?
  • The INCI name for sulfosuccinate should be Disodium Lauryl sulfosuccinate which gives a copious soap like lather with acyl isethionate(SCI).The cocco sulfate gives bar flash foam:not a bad formula in general.I  would not be concerned with reactivity of  LA with SCI: what is the Ph of 8% solution which is bath dilution for consumer use?Product is likely molded and not plodded as it lacks an internal plasticisor.There is much more but have to go to the gym.Do overnight weight loss for slop and 3 hour soak for cracking and compare to Dove and/or ordinary soap if you can get it.
  • pH affects many cosmetic formulations. It is however impossible to say if lactic acid has any effect on this formula just by looking at the LOI. It can theoretically be a just a trace amount from an extract.
  • Has anybody measured the pH of a solid shampoo? It has to be a lot lower than regular soap, I think.
  • -it should of course be added. No water - no pH.
  • You have to make a known %weight solution preferably at use dilution 8-10% before taking PH.
  • I've measured pH in soapy water before, but it would be interesting to compare a regular soap with a shampoo bar.
  • I don't see a reason why a shampoo bar of a formula similar to the one given here (with or without lactic acid) should, or would, have a similar pH to soap.
  • this bar is totally syndet (no soap) and expected ph should be 6.5--7.5.Also there is no water listed and bars of this type usually have 3-5%.
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