Hi Sarah,<quoted text>
How damaging is that process to your hair? Would it dry it out like other straigtening processes (i.e. japanese straigtening)?
A properly done Japanese straightening will not be drying to the hair. When the condition of the hair is changed, it is because the process was not done properly, or the hair was dry to begin with.
A smooth Control is a process very similar to a Japanese Thermal Straightening. The difference is that fewer bonds are rearranged. The ironing is usually done at a lower temperature.
Problems occur when these treatments are done by stylists with little or no experience. Sometimes when damage is caused, the hair cannot be repaired enough to do any other chemical process over it. That includes any hair color with a developer.
It is all about chemistry and if a stylist does not practice chemistry on a daily basis, they cannot solve the problems. There are multiple reactions that occur within the structure of the hair. Any straightening expert can tell you what the effects of the chemicals will be on the internal bonds of the hair.