How curly is your hair? Just wavy or spiral curls? My hair is spiral curly and fairly coarse. I usually use only a heat protectant. I would recommend anything from the Redken line... Smooth Down is formulated for heat and humidity resistance. I've tried it before and it smells great and really delivers on it's promises... With Redken, I've found it is better to use the whole "family" of products together, but if you're only looking for a styling aid, try the Smooth Down Heat Glide before you straighten. Using Redken products (all-soft line for me) has helped me to cut down on so much heat styling. Once I straighten my hair, I don't have to touch it with another heating instrument for the next week unless I choose to go curly instead of straight. Rarely, and I mean rarely, will I have to fix it due to humidity. I no longer have to relax it either. It just takes time... also, what kind of flat iron are you using? If you don't have ceramic, like a CHI, etc. I would definitely invest. It's a big chunk of money to throw down, but believe me when I say it will change you hair forever. Check on Ebay and see if you can come up with some good deals. If you have any questions, feel free to PM me. Good luck!