How does bleaching affect my hair?

Dr. Jeanne Morrison, PhD
Family Practitioner

Large terminal scalp hair shafts are composed of three distinct zones or parts - the medulla, the cortex, and the cuticle. The cuticle is an unpigmented, protective protein covering constructed in a sort of overlapping scale configuration. The cortex constitutes the majority of the hair shaft and contains the pigmenting that determines the color of the hair. In order to change hair color significantly, one's actual hair color must be neutralized so that the hair can be re-colored by hair dye of a chosen shade. A bleaching solution consists of an alkaline component that opens the cuticle and a bleaching component that irreversibly oxidizes the melanin pigment of the cortex, leaving the hair shaft the whitish to yellowish color of the keratin protein. The bleaching component is typically a hydrogen peroxide. In addition to stripping the cortex of pigment, this powerful oxidant interacts with the disulfide bonds within the keratin protein structure, weakening the structural composition of the hair shaft. Bleaching can be a damaging process to the hair and should be undertaken with care.

Bleached Blonde

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.