text: What's the difference between leave-in and leave-on products? — Cosmetic Science Talk
  What's the difference between leave-in and leave-on products?
  Sometime ago I read in a book that that leave-on would be a product that would be left on skin or hair after next wash and that leave-in would be a product that after applied would be rinsed after a few minutes from skin or hair. Does that make any sense? Could you help me understand this? Because people in Brazil use the terms in English but I see there is such a mess around here regardind that subject.
  A couple of years ago most people started using leave-in for any product that is not a rinse-off product.
  I've never heard the term "leave-in". It suggests to me that whatever it is requires permanent or semipermanent insertion into a body cavity.
  As far as I know the common terms are "leave-on" and "rinse-off".
  agree the terms should be leave on or Rinse off
  At Walgreens.com the search for "leave in" returns several results.
  Rinse-off is quite obvious it is any products that is rinsed off skin or hair.
  I really want to understand these terms because I wrote a blog a few years ago trying to make them clear in portuguese. But after that some questions rose and I want to update the information.
  Someone said once that "leave on" would suit skin care products and "leave in" would fit hair care products. I guess I'll run a qualitative market research though...
  For what it's worth 'leave on = skincare / leave in = hair care' makes sense and sounds accurate to me as a native speaker of English and consumer.
  We always called them "leave-in conditioners" at Alberto Culver when referring to hair products that were meant to be left in the hair & not rinsed out.
  Something left "on" the skin is sitting on the surface. Something left "in" the skin would have to be below the surface in some way.
  For hair, it's a little different. A conditioner, for example, could be put "on" your hair, meaning that it's on top of your mass of hair, and then it would be worked "in" to your hair, meaning that it was distributed through-out the mass of hair strands. Describing something that's actually below the surface of an individual strand of hair would require different terminology.
  A spray on detangler or hair spray would fall under leave on wheareas a conditioner with panthenol which penetrates the hair cuticle would be leave in
  Thank you all! This is more interesting than I thought it would. When I started this discussion I was expecting to get some definition statements from English native speakers. But it seems to me this is another case of marketing approach with no actual meaning that consumers pretend to understand and we at the laboratory try our bests to comprehend and turn it into a winner formula.
  Well the best option is to make it a quali research to get some definitions from both consumers and professionals.