Many consumers with textured hair would like longer and looser curls.  Products such as leave-on conditioners, styling creams and styling gels are designed to provide reduced curl shrinkage, whilst maintaining good curl definition.

The curl elongation assay at TRI measures the shrinkage of small bundles of coily hair as they dry from a wet to a dry state over several hours at room-temperature and 60% R.H.  Specially designed image analysis software is used to analyze photographs of the hair bundles and to determine the changes in hair length over time.

Validation studies have shown that this test can discriminate between hair treated with curl elongation products and untreated hair, and between different marketed formulations.  The curl elongation test is, therefore, a useful test for investigating product performance and for supporting curl elongation claims.