Dr Ernesta Malinauskyte, Director of Hair Research
Dr Philippa Cranwell, Technical Content Creator
In 2002, Beyoncé made her screen début as Foxxy Cleopatra in the film Austin Powers, Goldmember. As well as being an excellent female role model due to her sass and determination, one of Foxxy’s defining physical features was her large afro. As Beyonce shows, afro-textured hair can be used to form all sorts of beautiful and creative styles. Demand for products for this hair type are increasing, but what types of product testing methods are available to formulators of these products?
In recent years there has been an uptick in haircare products specifically designed for afro-textured hair types, also known was Walker hair-type 4, with numerous social media influencers giving hints and tips for afro styling. A recent explosion in blog articles, videos and websites devoted to the care of textured hair, particularly for preventing breakage and improving curl definition and hydration, has given the consumer more information than ever before. Things to avoid (chemicals, bleaching, hot irons), as well as ingredients or treatments are all discussed in detail, alongside the advantages of products containing natural oils, for example jojoba, castor oil or shea butter. For straight to lightly curled hair, nourishing hair fibers and maintaining moisturization, strength and hair condition are identified as key aspects to address, and as such, consumers have started demand these innovations. This means that manufacturers have had to move quickly to address market need.
However, substantiating claims in relation to afro-textured hair is difficult, and deciding which tests to use can be bewildering. This short blog post discusses four new claims substantiation tests developed at TRI for afro-textured hair:
Shine
Curl elongation
Breakage evaluation
Wet combability
Regardless of hair-type, shine is often associated with hair health, and hair health is associated with strength and vitality. This means that hair shine is a key consideration for consumers when using hair products. Measuring the shine of afro-textured hair is known to be difficult because the ‘traditional’ method of wrapping well-aligned hair around a barrel and measuring the intensity of the gloss-band does not work with this hair type (Figure 1.).
Figure 1: (a) The traditional system for measuring shine requires hair to be wrapped around a barrel, and reflectance measured; (b) The bespoke TRI Shine Box system, which allows measurement of shine for afro-textured hair without excessive tress manipulation.
The Shine Box system, developed at TRI Princeton, is an advanced technique specifically designed for assessing shine of afro-textured hair. Images of hair tresses illuminated by controlled lighting are taken and key data points such as shine count, total area/percent area of shine, can be determined, allowing for benchmarking of products and comparison of ingredients (Figure 2.).
Figure 2: (a) Raw data produced by TRI’s Shine Box; (b) Manipulation of data can give images ready for shine analysis.
Curl elongation and definition
When wet, afro-textured hair tends to elongate due to the weight of absorbed water, and the softening of the fibers. As the hair dries, it can shrink considerably. Products that minimize shrinkage usually act by depositing a layer of polymer or oil onto the hair fiber, or by reducing the rate of water loss from inside the hair. A new protocol at TRI, incorporating Image analysis can quantify length change of tresses during drying and can be used for product performance testing and claims support studies (Figure 3.).
Figure 3: (a) Wet tress immediately after treatment with shampoo product; (b) the same treated tress after drying at 60% R.H. for 9.5 h. The tress has shrunk by ~28%. Different products have been shown to lead to reduced shrinkage and maintenance of hair curl.
Due to the tight curls and twists, afro-textured hair is prone to tangling, which makes combing harder. This leads to more breakage. To reduce the forces, textured hair consumers comb/brush their hair in a wet state. Products that reduce tangling, usually by reducing friction between hair fibers, are therefore likely to reduce levels of breakage and lead to improved consumer satisfaction.
Repeated grooming experiments use an automated system to repeatedly brush hair tresses, inducing some hair breakage. These experiments can give insights into how a hair conditioning product or styling device can prevent hair breakage during repeated brushing or combing and can also give support to hair strength claims. For straight and wavy hair types repeated grooming experiments are always performed on dry hair tresses.
For afro-textured hair TRI has developed a new repeated grooming protocol that involves the manual combing of wet hair tresses. The use of wet hair better matches the unique consumer habits for this hair type (Figure 4). The new protocol involves wet combing while constantly rewetting of tresses. Validation work has shown that this method can discriminate between different types of hair care products and treatments.
Figure 4. Examples of the comb and tress used in wet breakage study
Most consumers comb afro-textured hair when wet because it is easier. This is because the water softens the curls and provides some weight to the hair, meaning detangling hair is facilitated. With this in mind, claims tests with hair in the wet state better reflect how a product may be used in real life and give more relevant data.
TRI has adapted the wet combing method used on straighter hair types for afro-style hair. The new protocol involves the creation of bespoke hair tresses from single-donor supplies, the use of a wider tooth comb, and the constant rewetting of the tresses throughout the experiment (Figure 5). This new method can be used for product performance testing and for claim support studies.
Figure 5. Afro-textured hair tress mounted on the comb testing apparatus with a wide toothed comb
Afro-textured hair has very unique properties, that lead to special hair needs. In recent years there has been an uptick in haircare products specifically designed for afro-textured hair types. However, substantiating claims in relation to afro-textured hair is difficult, since many techniques are not adapted to this hair type.
TRI has developed for four new protocols for testing afro-textured hair: shine, curl elongation, breakage through repeated grooming and wet combability. Contact us if you are interested in using our tests to support your product evaluation or claim support needs.
If you’re interested in the complexities of undertaking testing and claim substantiation on afro-textured hair, a detailed talk on this subject is available in the TRI library.
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