Shampoo surfectants (multiple?)

CdsgamesCdsgames Member
edited January 10 in General
We are developing a new shampoo formulation using SLMI (anionic very gentle on skin)
I know that surfactants are used in combination (anionic with amphotheric) to make it less harsh..but SLMI is already very gentle .
So do I still need an amphoteric ?


  • PerryPerry Administrator, Professional Chemist
    There is no requirement that you must use an amphoteric in a shampoo.
    In fact, you could make a shampoo using just water, SLS and a preservative.

    Of course, the question is - what do your consumers want?

    Generally, it's good to use a secondary surfactant in a shampoo. It helps with lowering irritation of the main cleanser but it can also impact foam & aid in thickening.  However, there is no requirement to have one.
  • Thx you Perry , its clear.
  • One more question . I am trying to add essential oils for fragrance to the shampoo . Of course I am diluting EOs in carrier oil to the level advised in Tisserand book .

      As per advice from this forum I used at 0.1% but the smell is very faint . I have to bump to 0.8% (at least) to have enough scent .

      Any elegant way to incorporate 1% oils in my shampoo ? Should I use an emulsifier ? ( I am only using SLMI as surfectant)
  • What percentage vof SLMI are you using? 

    You don't have to dilute your essential oil in carrier oil for shampoo. 
  • Right now I am trying 21%.

      I am a but leery to use neat EO on rinse of products . I am unable to find any data that supports it..
  • SylSyl Member
    Tisserand says you need to dilute your EO; you can dilute in carrier oil 1% or you can dilute in shampoo 1%, it is the same principle. Actually EO is safer in rinse off product than leave on since the EO will be washed off.
  •   I think that's a bad analogy . If you add neat EO to a bath you will get a serious skin reaction (it happened to me).

      EO is not diluted by water. I am not sure if surfectant will dilute EO in the sense that Tisserand explained . (carrier oil dilutes chemicals in EO so no allergic/irritation happens on the skin)
  • SylSyl Member
    You can solubilize your EO with polysorbate 20.
  • I applaud and apppreciate your dedication to safe usage. However, Tisserand is not a cosmetic chemist or perfumer, and is trying to keep people from hurting themselves or others while practicing aromatherapy. They use the easiest simple and general guidelines because they are not teaching chemistry, perfumery, or functional product formulation.
    For carrier oil vs shampoo or surfactant solution, the analogy works on a practical level. Different mechanisms are at work when comparing dilution in oil vs mixing into a surfactant solution, but either way the concentration is low because the essential oil integrates into the diluant in both.
    The clumsy explanation that I use for explaining to friends: There is no need to mix essential oils into carrier oil when using in a shampoo or body wash because of the surfactants in the cleanser. Surfactants are a one time use oil-to-water adapter with an oil grabbing side and a water grabbing side so they make oils mix with water to varying degrees. That is what makes them cleansers. Adding a carrier oil to shampoo is counterproductive because it reduces the available surfactant oil receptors for cleansing while not adding anything useful or desirable. Essential oils are not made of fatty acids and triglycerides like carrier oils, but they are mostly oil soluble or oil miscible chemicals. The EO is solubilized (grabbed and held) by the surfactant in the shampoo just like any oil is, but when EOs are used at safe amounts there is still oil holding capacity left in the shampoo so it will still work as a cleanser.
  • SylSyl Member
    @justaerin thank you!
  • Thx you Justaerin and Syl .

      I am removing the carrier oil .

    BTW...21% SLMI and 0.5% carrier oil was not producing good foam.
    Also , just to be extra safe , I chose EOs that are not known to cause irritation .
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