So where does this leave you?
As is often noted in studies, SLS, SLES, ALS and other Ionic detergents can be somewhat safely used in concentrations below 1% and if thoroughly washed off. However most personal care products include Ionic surfactants in the 15-50% concentration range, far exceeding the recommended safe levels.
Then there is the issue of washing the products containing ionic detergents off thoroughly. If you’ve noticed after a shower, when you step out and smell your skin, there is a light fragrance remaining? Well that’s because you aren’t washing the product off completely – and it’s not your fault. Due to the intricate complexities of physics, biology and chemistry, it is practically impossible to remove every single trace of product you have applied.
In a study published in the prestigious PNAS, a Molecular cartography of the human skin surface in 3D was taken. As seen by the image below, high quantities of SLES & CAPB, the two detergents tested for, was found in varying concentrations across the skin.