In this excerpt from his chapter on “Hair Care Product Claims,” Trefor Evans opens the door to the examination of strength and anti-breakage product claims.
Returning to the concept of consumer language versus scientific language, it is instinctive for scientists to think about hair strength in terms of the mechanical properties of fibers, and a variety of methods can be used to attain such measures. The “technical strength” of hair fibers will decline as the result of various treatments or conditions that are able to cleave strength-supporting bonds within the hair, but conversely a physical increase in strength of individual fibers necessitates the formation of additional bonding. However, the efficacy of conventional daily use products resides with surfactant surface science, rather than any reactive chemistry, and so the tensile properties of hair remain unaltered by these treatments.
This said, consumers generally do not assess their hair’s strength by twisting and tugging on individual fibers in an attempt to make a relative determination. Instead, their perception seemingly arises from visual observation of broken fibers in a comb or brush (or the immediate vicinity) during the grooming process. Accordingly, in “consumer language” the ability to greatly reduce this occurrence is likely interpreted as yielding “stronger” hair. The lubrication provided by conventional conditioner treatments will dramatically reduce fiber breakage by minimization of abrasion and fatiguing forces, while also reducing the presence of snags and dangles. Therefore, language pertaining to anti-breakage and “strengthening” are frequently prominent on hair care product packaging.
In principle, the presence of any lubricating constituent on a label ingredient statement would seem to legitimize such a claim; although there is often a desire to quantify the magnitude of benefit. Laboratory experiments to demonstrate this phenomenon involve repeatedly grooming hair tresses while counting the resulting broken fibers. In theory, this testing could be carried out by hand, although it is less arduous and more reproducible to use an automated device. The effectiveness of any product or treatment will be proportional to the dry state lubricity provided, which, as emphasized earlier, is purposely varied depending on the target hair type of the consumer. However, the benefit magnitude is also strongly related to the condition of the test hair. Chemically damaged hair leads to higher grooming forces, increased abrasion, and a higher likelihood of snags and tangles. There is also an increased likelihood of flaws and asperities which can propagate and lead to breakage. Accordingly, considerable amplification of breakage occurs as a result of these treatments, but, at the same time, enhanced product benefits are also observed.
By means of illustration, using our own standard methodology,1 treating virgin hair with a typical “moisturizing type” conditioner product leads to an approximate 60% reduction in fiber breakage. Double bleaching hair can triple the number of broken fibers in an unconditioned control, but this conditioning treatment can now provide 80-90% less breakage when used on this more fragile substrate. It is again noted that the number of women who chemically treat their hair in some form greatly outweighs the number of those who do not, and so it may be argued that experiments on chemically damaged hair represent a more realistic simulation of real life conditions. However, it is obviously important not to abuse this situation by using severely over-processed hair that no longer possesses relevance. Obviously there is no doubting the sizable advantage provided by such treatments, yet communication of this benefit must still be fair and reasonable.
1. TA Evans and K Park, A statistical analysis of hair breakage, II: Repeated grooming experiments, J Cosm Sci, 61, 439-455 (2010)
For more on this and other hair-related topics by Trefor Evans and other industry experts, visit www.alluredbooks.com to investigate Practical Modern Hair Science.
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