28 AFRICA FOCUS
Inclusivity: strengthening for African-textured hair
Aude Lemoine-Dessaint - Croda
Daily grooming activities like styling or combing alongside colouration, hair perms, straightening and thermal treatments, and even exposure to environmental aggressors like UV and pollution can lead to the degradation of hair’s structure and mechanical properties. Whether it is via mechanical or chemical means or a combination of both, the hair fibre will get damaged and become weak, dull, brittle, and more susceptible to breakage over time.1
Hair damage occurs globally and
affects all hair types regardless of ethnicity, but does it mean the effects are the same? Hair is something that we all have or at
least had at one time or another. Its basic structures are essentially the same across different ethnicities. Hair fibre is composed of protein, 91%, of which is approximately 50% keratin, and can be divided in two parts: the cuticles and cortex. The cortex is the thickest part and the primary source of hair strength, elasticity, and resilience. It consists of a complex internal structure formed from elongated cortical cells. The cuticle is the protective sheath that surrounds the cortex. It covers the cortex, acts as a resistant barrier and influences hair appearance, manageability and feel. However, the hair anatomy can vary
from person to person, there are genetic variances in hair type across ethnicities that generate differences in oiliness, cuticle size, hair shape and natural hair style (Table 1). At one extreme, African hair is the curliest, most elliptical, flattest, and driest of the hair types. It has the smallest diameter of hair types, which, moreover, varies radically along the fibre, leading to weak points and hair fragility. At the other extreme, Asian hair is the straightest, most round, and most oily hair type. The properties of Caucasian and Hispanic hair tend to fall in between these two extremes.
TABLE 1: AFRICAN, CAUCASIAN, ASIAN AND HISPANIC HAIR PROPERTIES. Hair Type Oiliness
Caucasian Oily/dry
CSD (µm) (Average)
Ellipticity Shape of hair Shape Amino Acids
29 – 96 (70)
1.17 – 1.41 Oval
Same
African Dry
46 – 120 (90)
1.68 – 1.98 Flat
Straight to wavy/curly Wavy to very curly
Same
Looking at the African hair structure, which is curlier and coily in texture, we see that there are more types of curls, leading to more complex characteristics. As seen in Figure 1, one of the classifications identified 8 types, from straight to wavy, curly and kinky.2 According to past studies, it has been found that: the tighter the curls are, the smaller the curve diameter is, the less the fibre will be able to stretch under stress i.e the more weak and fragile, making the hair prone to breakage when combed or brushed. The curlier the hair, the more areas of
discontinuity it will also have within the cuticle layer. Coily has fewer cuticle layers, less protection from the harm inflicted by combing, brushing, curling, blow drying, ironing and straightening. All of these differences lead to some
variation in the way damages affect the hair and how it responds to certain hair treatments. Consumers globally want healthy hair that is resistant to breakage but the inherent differences within the hair structure highlight the importance of adapting the solution. It is key to target specific needs and concerns and show hair care product performance on different hair types to fit personal routines.
Asian Oily
36 – 125 (92)
∼ 1.25 Round
Straight to wavy Same
Hispanic Oily/dry
30 –120 (70 –92)
1.17 – 1.98 Oval – flat-round
Straight/wavy to very curly
Same Scientists have focused on the
physicochemical properties of hair to develop products that enhance its feel, shine, colour, and overall aesthetics and meet the needs of consumers. Proteins and their derivatives are one class of active ingredients investigated and designed to impart some of these attributes. They are complex substances comprised of amino acids, which are the components of all living matter. Proteins are large macromolecules, also known as biopolymers, found in nature in an insoluble form, which can be hydrolysed to create ingredients that provide functional benefits from natural derivation. The mechanism of action can be dual; high molecular weight proteins have film-forming attributes, acting as a protective shield and offering effective conditioning whereas low molecular weight proteins are small enough to penetrate the hair fibre and provide moisture, integrity, strength, and flexibility. With a variation of molecular weights and
sources available, proteins are now well- established solutions with multiple properties and efficacies. The recent momentum of “protein free” claims in the Afro-textured hair care market have come to question the
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II Figure 1: Curl Type Classification. PERSONAL CARE July 2021
www.personalcaremagazine.com
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