(Skip to the last paragraph for the summary but i recommend reading it all
Bis-aminopropyl dimethicone is a amine-funtionalized silicone. This means that parts of its chemical structure were replaced by amino acids.
Just like in its original state, as dimethicone, bis-aminopropyl dimethicone is not water soluble but does not "build-up" as many other silicon can.
Here's what it does:
Hair, as we know, has an overall negative charge. Bis-aminopropyl dimethicone is a partly a catatonic (+) polymer, which is electromagnetically attracted to the strands' cuticles. It adheres to the strand's surface. Once attached, it spreads out to create a light film, imparting shine, silkiness and body.
Now, here's the bad part!
Removing it is tricky. It is afterall still a silicone. I read that it dissipates over time with relaxed usage and takes a few washings (using what, idk) to remove it completely in a shorter amt. of time.
BUT, and this is the good part:
being that this chemical is part nonionic silicone and part cationic polymer, it cannot attach to itself, meaning it cannot build up on top of itself with multiple applications. It simply isn't attracted to itself, like some of its stickier/nonionic/zwitterionic cousins are. This silicone simply slips off of the areas to which the silicone is already applied!
And the great part??
Areas of extreme cuticle damage are especially negatively charged. Bis-aminopropyl dimethicone and other amine-functionalized products are especially attracted to these areas, depositing their protein structures and working especially hard to make these areas look/feel healthier
Short if it: Bis-aminopropyl dimethicone is healthy&fortifying, though difficult to remove; but will not cause build up! I suggest using this every other wash to ensure your hair is getting proper nourishment from other products, because commercial products containing this (such as hello hydration) can improve the health/feel of your hair!
- Dara McGlown
The article below by Tonya McKay (whose articles i love!!!) is where i got some of my info: