Efficacy of Hair Relaxers

Human hair is classified into four types based on their curl pattern (straight, wavy, curly, kinky). The degree of curling of hair is dependent on the number of cysteine bridges formed between keratin proteins. For easier maintenance of hair, many people will use hair relaxers to straighten their hair. Hair relaxers come in a variety of classifications, such as hydroxide relaxers and thiol relaxers. In our lab, we are investigating the efficacy of different relaxer active ingredients to determine which relaxers are best at reducing cysteine bridges. The degree of cysteine bridge reduction is assess using a colorimetric dye, DTDP (above), which is specific towards free thiols in solution.¹

In addition, we are beginning to investigate methods to assess hair health after treatment (looking at susceptibility to protein extraction, investigating external damage by SEM). With this, we will identify relaxer conditions (type, concentration, treatment time) that offers the highest degree of cysteine bridge reduction while minimizing damage done to the hair itself.

Prospective student note: This project has been converted from a research project to an introductory training project for students who are interested in joining the lab.