I read this post on "why oil isn"t enough for our hair" and someone responded with I would like to know more about this layer via a discussion. Are there any substances to mimic or substitute this layer? This even makes me think of "evolution" and how some groups of people get specific characteristics. I've known about this layer making a difference since studying hair care but I have yet to see an in depth discussion on it. I'm looking for more than an answer of "it is how it is".