Straightening Irons can be potentially dangerous to the hair. A thermostatic control can be purchased to ensure that the job is done properly. The heat required to temporarily realign the shape of the hair has to be considerable but does not have to be at the highest setting. Thermal styling aids are a must to insure a protective barrier before one starts straightening the hair. If care is not taken, you may make your hair brittle! Steam-producing irons are less likely to dry out the hair, as these prodvide moisture, Teflon coated irons are best.
I have a client who flat irons her hair almost everyday. Her sides are so dry her hair is breaking off. I told her to give her hair a break. She doesn’t like her hair not flat ironed. She wants to keep her hair long but her sides are gradually getting shorter. The next thing I told her she could do is put some extensions on her sides. I would just be putting in some on her sides to match her back, so her hair doesn’t end up looking bi-level. This is one way if your sides are fine or thin to make it appear fuller. You are not looking at an expensive amount of money to put a few on your sides.