This post is here by request of one my regular readers who was natural but recently relaxed her hair and is unsure about whether or not she wants to stay relaxed. Commenting is disabled for this post as the fur tends to fly on such topics. This post is purely for education purposes and discusses what happens to hair when it is relaxed. You are warned that this post is long - I chose not to split it!
Before I delve into the science, let me start by introducing another new concept about hair. The cortex (the inner layer responsible for the strength of hair) is usually shown as one unit but actually consists of several fibres (known as fibrils) which are neatly and tightly packed together. (See diagram below).
Ok relaxers (i.e chemical hair straighteners) are grouped into two main groups
1. lye relaxers (contain high concentration of sodium hydroxide)
2. no-lye relaxers (contain high concentration of guanidine hydroxide)
Both of these relaxers work in the same way, lye relaxers tend to be harder to handle but are thought to be more effective than no-lye relaxers. These relaxers do have a high pH but pH is not the reason why hair gets relaxed. In fact if you reduced the concentration of the relaxer to about 1/10, it would still have a pH of 13 but it would not relax hair.
The two main factors (J Soc Cosmet Chem, pg 347-352, 1994)that cause hair to be relaxed are
1. Swelling of the cortex which happens when the relaxer separates the bonds within the proteins of the fibrils (see the diagram below)
2. A process known as supercontraction where the broken bonds essentially realign themselves into a configuration that allows the hair to be straight instead of curly.
The effect of the relaxer is permanent but variable.
Hair is very individual (are you tired of hearing that? lol). Different people will have different degress of straightness. Yes, straight hair can be relaxed too.
The effect of the relaxer is permanent. Reverting of the relaxer which is often reported is related to the true effect of the relaxer. Often after relaxing additional heat treatments are needed to produce the final 'poker' straight result. This will mask the true effect of the relaxer which can produce a range of results from nearly no discernible difference to the originial, to curly hair to super straight hair.
Damage to hair due to relaxing
Relaxers damage hair in two main ways
1. The cortex of the hair is significantly weakened due to expansion and bond breaking. The strength of relaxed hair is around 30-50% less than untreated hair. Meaning relaxed hair if pulled will break with half the force required to break untreated hair. (Cosmetic and Toileteries Magazine, Vol. 117, No. 11, 2002)
2. The cuticle is damaged by lifting (which can also break/chip or tear the cuticle). This has two effects. First and increase in porosity - meaning the hair can take up more water and hence expand even more(Cosmetic and Toileteries Magazine, Vol. 117, No. 11, 2002). Second the oil layers of the cuticle are disrupted. This is thought to contribute to the weakness of the hair cuticle in relaxed hair. (Int. J of Cosmetic Science, pg 1-12, 2002).
Mitigating Hair Damage due to relaxing.
1. Thorough washing off of the relaxer after application (15 minutes with shampoo at least 3 times, more if possible)
2. Hair conditioning to help smooth the cuticle
3. Ceramides are the new in thing. Ceramides are a component of the cuticle oil (See the previous diagram). When used as a leave in product they are thought to help strengthen hair. Replacing the oil on hair with any type of oil not just ceramides may be just as effective.
4. Minimize tension on hair, relaxed hair is weak.
5. Relaxed hair should not have another chemical process applied. This means no permanent hair colour.
General notes about relaxing.
1. Relaxing is potentially dangerous. The chemicals involved and their concentrations are at a level where there is chance of causing permanent injury. Respect the chemicals involved.
2. Hair in the scalp is not known to be affected by relaxing. This is the reason why retouching the hair is necessary. Retouching is the process of applying relaxer to new growth usually done after 2 months or more. It is not recommended to apply relaxer to already relaxed hair.
3. As a precautionary measure many people apply oil on areas where they do not wish to relax hair or do not wish to get burned (like ears, forehead, neck etc). While this is a good measure, it is no substitute for being extremely cautious. The reason why many oven cleaners contain high concentrations of sodium hydroxide is because it is excellent for dissolving oils and proteins. Therefore if a relaxer lands on an exposed part of the body (we are made up of proteins and oils), do wipe it up quickly.
As a scientist, I tried very hard to be objective and just present information. My real advice is don't do it - seriously, did you think I wouldn't say it at some point? lol!!! All joking aside, I do think the decision to relax hair is important. It is important to consider that curly hair as it is needs gentle handling. Relaxing will damage hair and consequently keeping the hair in good condition requires a lot of investment in learning.
IF you are having a difficult time with relaxed hair and want to know more on how to maintain it, then I will refer you to one of the relaxed hair gurus Sunshyne over at Hairlicious. Trust me, you don't want to ask me any questions, my relaxed hair way back when, was simply atrocious!