The Effect of Hair Dye and After-Care Treatments on Tensile Strength of Hair

The purpose of this experiment was to determine which hair dye and reconditioning treatment was least damaging to hair. First, two hair dyes were compared: one containing ammonia and the other being ammonia-free. After the hair was dyed, two treatments were tested on the hair: a store bought deep conditioner and a home created oil and egg mixture. These are used to compare the effectiveness of chemical products verses products with more of a natural base. When women or men dye their hair they usually don’t realize the damage can be lesser with different products. This research can be used in the real world, because being aware of different options will help for healthier hair.   People who dye their hair should know how it is affecting them and which products are best.

In order to measure the strength of the hair samples, the tensile strength was measured. This was done by hooking a hair strand to a force sensor and pulling the strand until it broke. This produced the tensile strength of the hair strand measured in Newtons.

This information was analyzed using three, two-sample t-tests: one comparing the hair dyes, and two others comparing the reconditioning treatments on each type of dyed hair. The results found that the ammonia-free dye resulted in the least amount of damage to hair. The oil and egg mixture was more effective than deep conditioner on the hair dyed with an ammonia dye. On the ammonia-free dyed hair, neither reconditioning treatment was more effective than the other.

Research Conducted By:

Caitlin Boback
Cousino High School

Kyla Semones
Cousino High School