How Lightener Works

12 October 2017

There are two ways to lighten your hair in the hair salon: with permanent haircolor or with a lightener product (don’t call it bleach…that’s for your clothes!). For the purposes of this blog, we will only be talking about lightener, and I will address how haircolor works in a separate blog.

But first…. a quick anatomy and chemistry lesson! A strand of hair is very thin (usually between 17-181 µm (millionths of a meter), but is chock full of interesting stuff. There are usually three layers to the hair: the outer layer (cuticle), the middle layer (cortex) and the inner layer (medulla). For this lesson, we’re really only interested in the cuticle (the “entrance” to the hair) and cortex (where all the pigments live). Natural haircolor is made up of two different types of pigment molecules (or melanin): eumelanin and pheomelanin. Eumelanin is the more common melanin, and makes up brown and black hair. Pheomelanin is much less common, and is responsible for red (copper) hair. A small amount of black eumelanin in the absence of other pigments causes grey hair. A small amount of brown eumelanin in the absence of other pigments causes blond color hair. Pheomelanin imparts a pink to red hue, depending upon the concentration. When a small amount of brown eumelanin in hair, which would otherwise cause blond hair, is mixed with red pheomelanin, the result is strawberry blonde.

Lighteners come in three different forms (oil, crème, and powder), but they all work in basically the same way. The main ingredient is ammonium persulfate, and when combined with an oxidizing agent (a hydrogen peroxide based product called developer), a chemical reaction occurs that removes the color from melanin. Actually, removing color is a misnomer because the color pigments are still there, and remain inside the hair, they are just colorless after the lightener has finished oxidizing. The different melanins oxidize at different rates, so you will notice hair going through several distinct stages of lightening in a specific order…. the brown or black is first to go, revealing strong red tones, which shift to orange, and then yellow, and finally light yellow. Hair should never be lifted past light yellow, as that is an indication that all melanin has been reduced. The color that you are seeing at that point is actually the color of the protein (keratin) that makes up the hair strand. Go past light yellow, and you’ve destroyed that protein, and the source of strength of the hair strand.

Using any type of lightener is considered a permanent process. The melanin has been made colorless, and those pigments won’t regain any color unless haircolor is reintroduced to the hair via artificial means. Hair that has been lightened can easily be compromised if the process is rushed or misapplied. Extra care must be taken to not overlap onto hair that doesn’t require it, or damage can result. Rushing the process by using a higher developer or heat can also result in damage to the hair (and the scalp!). This is a process best left to professionals in a controlled environment (like a hair salon, not your home bathroom). This process may also result in a sensitive scalp. This is one of the more harsh processes that can be performed in a salon. It’s advised to perform a patch test to see if you will be sensitive to the process, and avoid it if you are.

The process of lightening is useful and necessary to achieve many different looks, like platinum or super light blondes, and even the fantasy colors that are so popular now. Those colors only achieve maximum vibrancy if most (if not all) melanin is first removed from your hair, and so exceptional care must be taken to achieve the lightness necessary for vibrancy without damaging the hair fiber. Platinum and other super light blonde tones can also result in the same damage for the same reason.

Keep all this in mind when you’re visualizing a new haircolor on yourself. Proper care and caution must be exercised to prevent damage, and the best way to achieve a believable (and healthy) blonde is to place your trust in a licensed hairdresser with lots of experience.