Shampoos or shower gels can't deposit oils on hair or skin, do they?

If I'm not mistaken, even with the mildest surfactants
formulations can't deposit any oils on hair or skin, do they?

Surfactants always remove some at least oils, but they can't deposit them.
So all those oil containing shampoos claims are bogus
Am I missing something?

Comments

  • ozgirlozgirl Member, PCF student
    Generally I think the oils are there as claims ingredients and are just washed away.

    Silicone oils can be deposited on hair in the presence of Polyquaternium-10 from a shampoo base. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.553.8849&rep=rep1&type=pdf
  • Consumers don't know that its the electrostatic charge of certain silicone oils (amine-functionalized) that allows them to cling to your hair and make it feel soft so I'm sure they feel that plant oils do something similar.

    There's a product by Olay - the body wash with ribbons or something along those lines that deposits petrolatum on the skin and it does make your skin soft. The question though is whether it's cleansing the skin.
  • PharmaPharma Member, Pharmacist
    edited October 2019
    Surfactants have a so called critical micelle concentration (CMC) above which they form micelles and solubilise oil, grime, and dirt. Below, all molecules are in true solution though they may still reduce surface tension and hence foam more or less but they won't stabilise oil droplets any longer. Therefore (in theory) a concentrated shampoo can hold a lot of oil and "drop" it once diluted enough. Sure, such a product won't cleanse well either unless used pure on wet hair/skin = above CMC = cleaning and then rinsed off with a lot of water = deposition of oils (and grime and dirt...). Well, probably a good part of the grime and dirt will stay afloat and not deposit back onto hair/skin.
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