How do hydroxide relaxers straighten the hair

Now that I have embraced my natural hair, I look back on the relaxers that I depended on for so long to find out what they really did to my hair. Relaxers come in a range of brands, strengths and consistencies, but how do they work? Instead of using heat to straighten the hair, chemicals are used to loosen the tightly set curls. Hydrogen and disulphide bonds are a main factor in determining the curl pattern of the hair.

Hydrogen bonds are bonds that form between water molecules, and are responsible for hair curling as it dries. When hair is wet, the hydrogen bonds are broken. As it dries, the bonds reform, as do the curls. This is why hair can be manipulated by using rollers as a temporary alternative to relaxers.

As the hair dries around the rollers, it holds its new shape once they are removed. Disulfide bonds are much stronger than hydrogen bonds. These bonds form between sulfur atoms in hair fibres in order to provide strength in addition to the formation of curls.

These bonds cannot be broken by water like hydrogen bonds, so hair relaxers are used. The chemicals present in hair relaxers break the disulfide bonds. This permanently straightens the hair. However, breaking these bonds makes the hair more susceptible to breakage and split ends.

Illustration of disulphide bonds in hair fibres breaking due to the use of hair relaxer. The relaxers are strong enough to break the disulfide bonds in hair fibres and consequently alter the structure of the curl pattern. This because of their typically high pH. In chemistry, pH is a numeric scale used to state how acidic or basic a substance is.

If it has a low pH, it is more acidic and if the pH is high, it is more basic. Hair relaxers are basic, with their pH ranging from 9 to 14 to ensure that they are strong enough to change the hair structure. There are different types of hair relaxers available of varying strengths and made up of different chemicals.

Thio short for ammonium thioglycolate relaxers are much thicker in consistency than other relaxers, which makes them easier to apply. They have a pH value of at least 10 to ensure that enough of the disulfide bonds have broken. The relaxer is then rinsed out and a neutraliser used to bring the hair back to its original pH value of 4.

However, lye relaxers work in a slightly different way. In this process, lye is the active ingredient. Lye is a mixture of sodium hydroxide , water, petroleum jelly, mineral oil and emulsifiers. The curls are then loosened as the hair fibre swells open. However, the amount of lye in the relaxer can vary, so weaker products can minimise the extent of damage to the scalp.

Lye relaxers typically have a pH between 12 and 14 and do not require a special neutralising step, unlike thiol relaxers. Increasing awareness of the potentially harmful effects of sodium hydroxide led to the development of no-lye relaxers. The pH is a measure used to determine the acidity and alkalinity of a substance. The scale is represented by numbers ranging from 0 to 14 where 7 is neutral.

Greater than 7 on the pH scale is more alkaline and less than 7 is more acidic. The pH of hair ranges between 4. Lye relaxers range from 12 — 14 and no-lye relaxers range from 9 — Following a relaxer you should always cleanse with a Neutralizing shampoo.

A neutralizing shampoo will ensure that you remove all traces of chemical residue and restore the hair to its resting pH level of 4. The pH of a hydroxide relaxer is typically 13 or higher which is considered a high alkaline concentration.

Therefore an acid-balanced shampoo must be used to neutralize the hydroxide, and to return the hair and scalp to a normal pH level. Processing times vary from client to client. However, most processing times are a maximum of 20 — 25 minutes. If you relax the hair until it is bone straight, you are essentially over relaxing the hair. This removes any degree of elasticity, thus weakening the hair.

Over a period of time of continuous over relaxation, blow drying and hot curling, the hair will become damaged and prone to breakage. Thio relaxers are also used to straighten hair. The primary agent, ammonium thioglycolate ATG is also used in permanent waving. Hydroxide relaxers and thio relaxers should not be used interchangeably.

Overlapping these chemicals can cause extreme damage to the hair, and can result in hair loss. Thio relaxers differ from hydroxide relaxers in a few ways. The pH of thio relaxers is typically around 10 whereas the pH of hydroxide relaxers is approximately Also, an oxidizing agent like hydrogen peroxide or sodium bromate is used to neutralize thio relaxers. During this process the disulfide bonds are reformed that were broken by the relaxing process.

When using hydroxide relaxers, the broken disulfide bonds are permanently broken and cannot be formed again. Oxidizing agents should not be used with hydroxide relaxers. FREE U. Types of Relaxers Chemical hair relaxers are designed to straighten extremely curly, coiled or tightly coiled hair by breaking the disulfide bonds found within the cortex layer of the hair.

What are the different types of Hydroxide relaxers? What is the difference between Lye and No Lye Relaxers? What is a Low Lye relaxer? What if my client has a sensitive scalp? What is pH?