Hair Penetration By Conventional Cosmetic Ingredients

These are not current research studies.

This one is from 2005, and is about the quaternium ammonium compound, cetrimonium bromide, being able to be absorbed into hair because of its low molecular weight. Again, the hair preparation, is not clear to me. However, it had to have nothing on it that could prevent absorption for the tests to be accurate. The catch? "Quats" as they are often referred to are highly toxic and are recommended to be used only in very small percentages in hair care. They are not used on their own but in a formulation. In order to get the absorption benefits from it, the hair would need to be well clarified and the formulation would have to be free of barrier coatings like waxes and other high molecular ingredients that would interfere with its absorption. That is different to toxic consituents in ingredients being absorbed into even intact skin in creams, for example, see Page 2 "Safety". 

This one, from 1995 is most interesting to me, as it concerns the absorption of various silicone emulsions used as a pre-treatment before chemical hair dye and bleach to help prevent oxidative hair damage. The hair was prepped or prepared, by washing it. This 2002 patent by L'Oreal, uses the 1995 study as a reference.

So, what happened to all of that between then and now?

There appears to have been or is some difficulty in stabilizing such emulsions.

Coconut and argan oils used as a pre-treatment before the application of conventional peroxide containing dye, help increase dye uptake while helping to prevent processing damage and condition the hair. Used the same way before the application of bleach, or only conventional peroxide, they help prevent such peroxide oxidative damage too, while not hindering hair colour lightening, and they condition the hair at the same time. See http://ktanihairsense.blogspot.com/2009/11/part-1-of-3-part-series-on-innovative.html.