Again, please excuse the lack of scientific background that could make this question really dumb
I've read in the blog a previous question on thickeners and skin penetration, and I was wondering if penetration could be hindered by using oil based products in the first steps of a routine, specifically oil based cleansers and balms, or even OCM. For the first ones, I understand that the way they emulsify is through surfactants that allow products to be rinsed off (this would include oil as well I understand), but supposedly one of their advantages is the way they don't strip the skin, even leaving a bit of film, and if that film comes from an oil, could it not be at least a bit occlusive and therefore prevent penetration of the next actives in the routine? I guess with OCM, if this was the case, the effect would be more pronounced.
A sub question: are all oils inherently occlusive? Perhaps just if you just slather on like a gallon?