Understanding the water consumption associated with the use of hair care products: The impact of six hair characteristics on rinsing shampoos and conditioners.

Abstract

Objective: Environmental life cycle assessment of hair care products shows that the highest environmental impact is associated with the use phase, rather than conception, production, packaging, distribution or disposal of the products themselves. To measure the water consumed in the use phase, an innovative and cost-effective methodology was developed and tested to measure the water consumed to rinse off hair care products (rinsability).

Methods: Over 4 months, we tested the rinsability of 10 shampoos and 10 hair conditioners applied to 148 females, split between six hair characteristics: length, volume, dryness, thickness, curliness and damage. The volunteers were received in a hair salon on 20 different occasions for about 30 min each time. A team of hairdressers was specifically trained to detect two indicators of when a product is rinsed: a visual disappearance of the product and a clean touch. The volunteers were asked to have their hair washed at home 48 h before their arrival, using a standardized shampoo to control for sebum apparition.

Results: According to this test, on average, 7.1 L of water are needed to rinse a shampoo and 6.3 L to rinse a hair conditioner. However, there are significant differences depending on hair types: long and abundant hair requires more water to rinse shampoos and conditioners, whereas hair thickness, curliness, dryness and damage do not significantly affect the water required.

Conclusion: We suggest that data on product rinsability are essential when considering the water footprint for shampoos and hair conditioners. This method could be adopted for industry-wide experimentation to assess the water footprint of products and set reduction targets.