There is whole process to keep hair straight. I will recommend you to use Rusk shampoo, conditioner for flat iron and then special spray while straightening. (Rusk for flat iron, yellow products). Spray is really strong and is covering your hair with the soy protection layer. I don't recommend biosilk - to much of softening factor. Product has to cover your hair, keep it dry (not oily) and protect from humidity to enter. If you won't find Rusk products, try Chi or other marks.