Whether consumers pay to have hair professionally dyed or spend time doing it themselves, they want effects that last. Sabina Wizemann (SW), senior chemist of the Health, Beauty and Environmental Sciences Lab at the Good Housekeeping Institute, has evaluated shampoo and conditioner pairs to identify the best performers for hair dye retention. In a recent interview, she explained how she tests these products, analyzes their efficacy and claims, and which duos exemplified the highest efficacy, compared with other products. Following is an adapted excerpt; access the digital magazine to watch the full interview.
C&T: How have you tested the color retention efficacy of shampoos and conditioners designed for color-treated hair?
SW: The Good Housekeeping Institute tested shampoos and conditioners for color-treated hair in both lab and consumer tests. Initially, when our lab received the products, they were categorized according to their primary claims and formulations. After this was completed, we met with the institute and editorial team to select contenders based on substantial claims, availability and price points.
In the lab, we conducted a wet hair combing test and color fade resistance test. In the wet hair combing test, shampoo and conditioner duos were compared for ease of combing or conditioning using Instron. We used eight bleached dark brown hair swatches for each shampoo and conditioner pair in our product roundup.
The color fade resistance test is done on natural white/gray hair dyed with red oxidative or permanent hair color. For this test, we used six hair swatches for each pair and utilized lab equipment such as a swatch wash station and an accelerated weathering station. The samples went through 20 wash/dry cycles and 10 hr of UV exposure to simulate natural wear between colorings.
We used a spectrophotometer to quantify the color of the freshly colored control as well as the weathered swatches and calculated the total color change/fade for each product pair.
For the consumer portion of our study, each shampoo and conditioner pair was shipped to 22 women across the United States. Products selected for our tests included shampoo/conditioner pairs with claims related to hair color protection and with pre-determined launch dates.
Before being selected, the women were prescreened by our team’s pre-determined criteria. For example, we chose women who color their hair regularly and use permanent hair dye, among other prerequisites. They used the product for two weeks, then completed a 20-question survey.
The entire assessment from inception to the final report lasted approximately four months.