What do you want to know about bleaching?

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References

Hair Bleaching

Hair Bleaching

Hair contains two major and two minor pigments embedded within the protein chains of the hair fibres. The major pigments are melanin, a brown-black polymeric pigment also responsible for skin colouration, and phaeomelanin, an iron-containing red pigment derived from melanin. The two minor pigments are the yellow pigment oxymelanin and the brown pigment brown melanin. The relative proportions of these pigments determined one’s hair colour. For example, high melanin content gives black or dark hair, while low melanin and high phaeomelanin content results in blond hair. Oxymelanin is also present in blond hair, this pigment is formed when melanin is oxidised during bleaching.

Hair bleaching is a process of lightening up the colour of the hair, which is determined by the quantity, type and distribution of colour pigment inside the hair. This process radically alters the original proportion of the melanin pigment and the bleached hair that will be more fragile and drier after bleaching as the bleach reacts with the hair proteins and reduces their molecular weight. Other bleaching side reactions crosslink the smaller protein fragments, making them more brittle and weaker. Hence treatment is usually required after the bleaching of hair.

If the colour of their hair is darker than the colour they want to dye their hair with, people will usually bleach their hair before dyeing it.

Hydrogen peroxide (H₂O₂) can be used to lighten hair into lower-molecular-weight melanin degradation products through a redox process but it does not work well on black hair.

Hair bleaching damages the hair, so instructions must be followed closely.

                         Colour of hair before bleaching                       Colour of hair after bleaching

1. Don’t wash hair on the same day when you are bleaching it as the washing of hair removes the oil produced by the scalp that aids bleaching.
2. Apply bleach to the ends of the hair first. Because the roots will lighten faster than the ends of the hair due to the scalp-produced oil.
3. If the hair is of a darker colour, bleaching is done more than once but allow a day or two between bleaching.
4. After treatment of the hair is important. Eg oil treatments.
5. Animal protein conditioners are added to soften hair after bleaching.
6. Hair bleaches usually contain ammonia to adjust the pH above 9, which makes the oxidation more efficient.
7. Hairdressers can use other bleaching chemicals in place of H₂O₂. Alternatives include the more expensive perborates, eg NaBO₃.4H₂O, which release H₂O₂ by reacting with water and chlorine-based bleaches which are less commonly used because they may discolour the hair and leave it with a greenish tinge.

Epilogue

By this time, hopefully, you would have had more insights about the causes and effects of bleaching of the various parts of our body. To bleach or not to bleach? Is it worthwhile to risk the high chances of causing damage to our precious teeth, skin or hair, in exchange for our perceived view of beauty? Some said that ‘Beauty is in the eye of the beholder’ and ‘Being natural is beauty in itself’. What do you think?