Lye or No Lye- Understanding The Chemicals That Are In Your Relaxer

It was at the turn of the twentieth century that what we now know as hair relaxers was created and by a small accident, Garrett Augustus Morgan was working in a sewing machine repair shop where he was attempting to invent a new lubricating liquid for the machine needle. He wiped his hands on a wool cloth and when he returned the next day, he found that the cloth was smooth where he had wiped his hand. The lubricating liquid had changed the texture of the wool. Excited by the possibilities, he experimented on a dog with curly textured hair and the same result was obtained.

Morgan eventually tried the lubricating liquid invention on his hair and dubbed it a “hair refining cream”. That was the first chemical hair straightener and from then till now people with curly hair types have been using this cream to relax the curl pattern in their hair for it to be permanently straight.

Lye Relaxers

A lye relaxer consists of sodium hydroxide (also known as NaOH or lye) chemicals with a pH factor of 10 to 14. The higher up on the pH scale, the more alkaline is the product and the faster it will break down the hair bond. Mixed with other ingredients: petroleum jelly, emulsifiers, water and mineral oil, a creamy lotion is created. This creamy relaxer or lye cream when placed on the hair penetrates the hair’s protein structure and breaks down the hair bond; in the process it loosens the curl pattern of the hair. The sodium hydroxide content varies in different relaxer brands and are labeled as mild or strong. Sodium Hydroxide is quite strong and produces a longer lasting effect than other relaxers. It makes hair straighter and smoother. However, it is such a strong product that it is the active ingredient in drain cleaners (now banned in several countries because of its potency).  The damage potential of sodium hydroxide is really high so handlers of this chemical have to use it with care.


There are three main types of no-lye relaxers: potassium hydroxide, which operates on the same general principle as sodium hydroxide but with a weaker alkaline agent, lithium hydroxide and guanidine hydroxide. Guanidine hydroxide is a mixture of calcium hydroxide and guanidine carbonate. They are usually packaged separately and then mixed before application. Guanadine hydroxide is still a powerful chemical, however, its power is tempered somewhat by being a tad bit lower in alkaline than sodium.

Another no-lye relaxer is: ammonium thioglycolate (perm salt), when applied gives the hair permanent waves. Perm salt is a chemical reducing agent, which weakens the hair’s cystine bonds and strips the natural oils even more thoroughly than the alkali hydroxide products. After this process the chemical has to be oxidized with hydrogen peroxide or sodium bromate. This should explain why permanent waves require moisturizing all the time.

A much weaker no-lye relaxer option is ammonium sulfite/bisulfite. They are much weaker than other no-lye chemicals and work much slower than their chemical counterparts. They also have a significantly lower alkaline pH.

So which is better- lye or no-lye relaxers?

Let us first explore the similarities:

  • They are both chemicals as we explored above, hence they both break down the hair.
  • Before using one or the other you have to prepare your hair for a chemical process, which means your hair has to be conditioned and your scalp has to be healthy. Damaged hair with chemicals equal hair loss.
  • Improper use of both chemicals can cause burns, hair loss, over-processed or fried hair.
  • They are both irreversible once done. The hair does not go back to its natural state after a couple of weeks. You cannot sweat out a relaxer. To get rid of a relaxer you either have to wait until your natural hair grows back or cut it off altogether.

The differences:

  • Sodium Hydroxide is very strong, it creates a smoother or straighter effect than any other chemical ingredient used in relaxers. If there were a competition as to which chemical is the strongest, sodium hydroxide would come first.
  • On the other hand, Guanidine Hydroxide, Potassium Hydroxide and Lithium Hydroxide are somewhat weaker than their Sodium Hydroxide counterpart. This weakness is not that significant, so they can still get your hair dramatically straighter however, they leave the hair with some amount of tensile strength.

So which relaxer should you choose?

I recommend going with a relaxer that does not make your hair absolutely straight. The problem with bone straight hair is that when you break all the hair bonds to within an inch of its life it will start to fall. There will be no strength left in your hair to at least fight to stay on your head. This may be a simplistic reason but the facts speak clearly. The straighter you go with your hair, the more damage is inflicted on it. So that said, I say go with a no-lye relaxer. It’s still chemical but not as harsh. If you cannot afford the more expensive no-lye relaxers, you have to make up your mind to treat your hair especially well when you relax with a lye relaxer. Many women use lye relaxers and they have a thriving head of hair, the decision is of course up to you.

If for any reason you are using a lye relaxer and you intend to start using a no-lye preparation, prepare for some hair shedding. You can mitigate this shedding by conditioning often and maintaining your protein and moisture balance. Also remember to avoid switching between lye and no-lye relaxers regularly if it all, they are two different chemicals and they work differently, switching relaxers regularly will damage your hair.

What about Waves or Perms?

This type of hair processing is largely out of style because of the process, and how damaging it is to hair in the long run.  Permanent waving is usually done in two basic phases: reduction and oxidation.

During the reduction phase, approximately 20% of the hair’s cystine bonds are broken into cysteine (or half cystine bonds). It is in this phase that the hair assumes its new configuration. In the oxidation phase, 80-90% of the broken bonds are reformed to lock in the new curl formations.

For black women with kinky curly hair the permanent waving process is done in four stages, first, ammonium thioglycolate is applied to the hair, then a reshaping lotion is applied, then a solution containing sodium bromate is applied then glycerin and propylene glycol is applied to moisturize the hair.

This type of treatment is very severe on the hair and overtime can result in limited length retention.

According to Dr. Ali Syed on the site, the following four facts should be considered before you wave your hair:

1. Ammonium thioglycolate, the active ingredient in permanent waves, is extremely drying to the hair. Proper moisturizing is therefore a must, accomplished by applying glycerin and propylene glycol-rich sprays, cremes, lotions and/or gels on a frequent basis.

2. With repeat perm applications (every 12 weeks or so to treat new growth), the previously permed hair loses additional cystine bonds and incurs greater damage. As a result, the hair is further dehydrated, and the ends may become straight, stringy or broken. A great deal of care, therefore, must be taken to condition the hair well after every shampoo, and the ends should be trimmed with each repeat application.

3. As sleeker styles come into vogue, many clients have requested transitions to relaxed hair. Permed hair definitely should not be treated with standard relaxer formulas since sodium hydroxide, as well as guanidine hydroxide (no-lye formulas), react very rapidly on permed hair, inducing excessive damage. Clients must be counseled to wait until there is sufficient new growth before a relaxer treatment is applied, and advised that eventually the permed portion of the hair will have to be cut off. “Restructuring” from curly to straight may be attempted with mild guanidine hydroxide relaxers when there is sufficient new growth. In this process, the relaxer is combed through the previously permed hair only during the final 2-3 minutes of processing.

4. Despite the marketing promises of many brands, permanent waves cannot effectively go through significant style transformations (i.e., from the original curly texture, to a straight relaxed look, and back to curly again) on a repetitive basis. The client will not like the end result. Manipulation of permed hair with heated appliances such as blow dryers and curling irons, and even roller sets, will weaken the curl pattern significantly. After repeated attempts to achieve a relaxed look, the perm will not spring back to its original form.

So should you permanently wave your hair?

My informed response would be, ask yourself the question, do I want permanently wavy hair or do I want to wear my hair straight sometimes? If you want to wear your hair straight sometimes, maybe you should relax instead. You can have curly styles with relaxed hair but having straight styles with permed hair can make you lose your hair overtime.


Henderson-Brown Stephanie, Avadis Catherine, Advanced Hairdressing: A Coursebook for Level 3, Nelson Thomes Ltd, 2004

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  3. Breaking Hair- Remedies
  4. 5 Easy Ways to Thicken Relaxed Hair

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