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What Happens to Hair When we Bleach it?

All of us use bleach or lightener, whatever you want to call it, to some degree behind the chair.

I want to offer some clarity and perspective on WHAT actually happens when we put bleach on a hair strand.

But before we get into it, let’s break down what we use to lighten hair - bleach and developer. What are they, what do they do, and how do they work?

First up, bleach.

Bleach contains:

1. Alkalizer: an alkalizer has 2 main jobs:

  • To soften and swell the hair.

Remember, hair's happy place is between a 4.5-5.5…anything with a pH higher than that will soften and swell the hair fiber.

Now, anything above a 7 on the pH scale is considered ALKALINE.

The higher the pH of the product we put on the hair, the more the hair will swell. This is because hair typically takes on the pH of the environment that it's in.

Most lighteners range between 10.0-12.0, which means the hair is incredibly swollen sometimes up to 25-30%.

  • To start the chemical process.

The alkalizer is the catalyst that initiates the chemical reaction with the developer. Essentially, once the developer (which is acidic) is mixed in with the lightener (which is alkaline) a chemical reaction occurs and the developer begins to release its oxygen.

2. Persulfates

Persulfates are inorganic salts that are designed to break down an organic substance - HAIR.

The 3 main persulfates used in bleach are:

Ammonium persulfate

Potassium persulfate

Sodium persulfate

Most lighteners have a combination of these salts.

Lastly, developer.

Developer is an oxidizing agent that, when mixed with an alkaline substance, creates a chemical reaction that degrades, breaks down, diffuses, and fractures the hair fiber.

Remember the hair fiber:

Is made up of 95% keratin protein (amino acids)

1-2% melanin

Other minerals

So when we mix up our bleach with our developer, a chemical reaction occurs:

1- The alkalinity of the lightener causes the hair fiber to soften and swell, giving the developer access through the CMC into the cortical fibers of the hair.

2- The alkalinity also initiates the developer to start releasing its oxygen.

3- The persulfate salts, in combination with the developer, begin to break down the WHOLE hair fiber..the protein and the melanin.

4. Melanin is trapped in melanocytes, and when exposed to alkalinity + oxidizing agents, the melanocytes rupture and the melanin gets degraded.

5. The more the melanin is degraded and broken down, the more light passes through the hair fiber creating a lighter result.

What is going to determine HOW this process happens, how fast it happens and what the final result will be is based solely on the hair fiber itself.

Each fiber is unique in texture, porosity, and the type of melanin that's dominant in that hair fiber.

This is why some people lift extremely brassy while others lift slightly warmer.

I teach all about this in The FUNdamentals course shop, you can click the link below to check it out and get $500 off!

I hope this was helpful for you.

Understanding fully what we are doing BTC is KEY to making better choices in the products we use and build our confidence to tackle any hair color situation!

Happy Hair Coloring!


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