I straighten my hair at least once a week. With a flat iron. And one my best friends is this NOVEX Brazilian Keratin spray. I got it from Embelleze, and I really really like it. It's heat protective, which means that avoids your hair from frying up from the heat of the iron. I apply it on my hair -- focusing on the ends because their more prone to burn -- and when you use the iron over it you can actually see it evaporating!. It looks like smoke, but it's actually the product evaporating! And while it evaporates, it consumes the heat that could possibly damage the hair.