Hair that won’t straighten
There are two different types of protein within the cortex of the hair. They are called either low sulphur proteins or high sulphur proteins. Low sulphur proteins are spring-like in shape and account for nearly 60% of the cortical protein. High sulphur proteins account for nearly 40% of the cortex. They can be thought of as “glue” which locks the “springs” in place. When hair is being chemically treated/TRd, the “glue” is softened and the springs move to a straightened form. The glue is then “hardened” to lock the springs into their new straight position. The “glue like” protein needs time to harden. Thus, explaining why you should not wet or shampoo the hair for 48-72 hours after the straightening service.
I know this is complicated but reason it through. If you have a history of complain of poor hair straightening/TR results, it is unlikely that this will be corrected regardless of straightening crème solutions, technique, or skills. The reason is probably your hair itself. While not completely proven, it appears that certain individuals have a higher percentage of spring-like proteins. The normal percentage is about 60% “springs” and 40% “glue”. A higher percentage of spring-like proteins mean that the hair can readily be stretched but because of the lower percentage of “glue,” the straightness is not held very well and reverts back. While the hair looks and behaves normally in other ways, it does not hold a permanent straightener or set as well as others.