Stearamidopropyl dimethylamine is one of the leading 'replacements' for silicones in conditioners (For Tresemme Naturals fans - this is the lead surfactant in your conditioner). I placed the word replacements in quotes because it is not always strictly a replacement, sometimes it is added in conjuction with a silicone as happens with Herbal Essences (so in short, do not think that seeing it on the ingredient list means that the conditioner is silicone free).