There are a wide array of styles and textures available to today's salon clientele. With so many options, the ability to switch from one look to another has never been more important. To answer the question - can relaxed hair be stripped? - it is necessary that we first understand hair chemistry and the lanthionization (relaxation) process.
Hair, or keratin according to chemical terminology, is made up of polypeptides. (Polypeptides are made up of amino acids - the basic units of protein). Polypeptides are aligned in a parallel fashion and are cross linked with cystine bonds (also called disulfide bonds).
When Afro hair is chemically straightened with sodium hydroxide-based relaxers (i.e. sodium hydroxide) approximately one- third of the cystine bonds are changed to lanthionine bonds. Note that lathionine bond has only a single sulfur atom; one sulfur atom less than the cystine bond of virgin hair.
Lanthionine bonds are very stable, meaning that they are no longer susceptible to further change. Thus, once cystine bonds have been changed with a relaxer treatment, there is now no way known to science for the lanthionine bonds to be changed back to cystine bonds. In other words, chemical relaxation is a permanent process that cannot be reversed. Why then do you hear clients saying that their relaxer "didn't take, went back, or reverted?" Or why do professionals sometimes witness a frizzy appearance on the portions of their clients' hair that were previously relaxed? Actually, there are a few explanations:
The first is that the hair was insufficiently straightened in the first place. If, indeed, less than a third of the cystine bond were converted into lanthionine bonds, the hair may look straighter on the day of the treatment, but will eventually appear to revert. To prevent this occurrence, the proper relaxer strength must be selected and adequate time given to the smoothing segment of the process.
The second possible explanation is that something was done to the hair to rough-up the cuticle (i.e. improper shampooing, the use of pH-imbalanced products, incorrect combing and brushing, etc). Also, due to the fact that relaxed hair is more porous than virgin hair, humidity can give hair that "less-than-straight" appearance.
The third possibility is a rare phenomenon which I call "natural reversion." Although this is a hypothesis and not a documented and scientific fact, it is one that has been discussed over the years among some in the scientific community. It is established that when hair is lantionized (relaxed), the natural spatial arrangement of atoms and molecules in the hair is changed. The "natural reversion" theory purports that this rearrangement is so stressful and uncomfortable for the atoms and molecules that they fight to return to their original positions. Therefore, within a week or two, they may revert to their original status.
Keep in mind that even as theorized, natural reversion is a very, very rare occurrence that is experienced by only an infinitesimal number of people. By and large, even if relaxed hair seems as though it has reverted, don't be confused... most likely, it hasn't.
Since the early 1980's, there have been at least a couple of products that claimed to strip relaxed hair so that it could then be permanent waved. These attempts were not successful. Equally unsuccessful are the mythical "home remedies" of rinsing the hair with highly acidic substances such as vinegar.
None of these methods have been scientifically proven to work, and they can actually cause damage by ruffling the cuticle and disturbing the balance of amino acids and polypeptides.
Should a client ever want to return his or her hair to its natural state, the only way is to cut off the relaxed portion once there is adequate growth. For those who now have a natural head of hair and are not comfortable with the idea of a permanent texture change, it's best to press the hair to achieve straight styles. Pressing is a "physical" alteration that is temporary. Lanthionization is a "chemical" change that is permanent.