Ethnic hair structure is unique and warrants special attention and care. The diameter of tightly curly hair is more elliptical in cross-section compared to Asian or Caucasian hair. Cuticle layers vary around the perimeter, which causes a coarse hair texture. Fiber diameter varies along the hair shaft, which make style control very difficult. Sebum migration to the hair shaft is very low and not evenly distributed due to the large diameter and tight curvature along the hair fibers. In general, ethnic hair tends to knot and tangle, and is very dry, frizzy and fragile. It breaks easily, especially at the curvature area. This makes breakage the primary problem for ethnic hair.
For ethnic hair, washing is a delicate process and very time-consuming; therefore shampoo is used less frequently. Only 4% of black women use a shampoo every day, compared to 34% of women overall2 and 19% use styling products (e.g. setting lotions, creams) every day.
In general, ethnic consumers are less concerned about the cost of a product and are willing to spend money on products that address their needs. In the past, relaxer was the largest segment in ethnic hair care while styling aids, hair dressing/moisturizing and conditioning products and hair colorants were also very popular. But the use of relaxers is declining due to the Naturalista trend. Rather, the Naturalista trend promotes the sale of styling and conditioning products. The use of shampoo is also on the rise.
Some consumers want a partial curl; others prefer a complete removal of the curl. To achieve this, relaxers or straighteners are used. For cleansing and conditioning a conditioning shampoo is used weekly, followed by an intensive conditioning treatment (rinse-off plus leave-in ideally) and finally, a setting or wrap lotion for frizz control. Products intended for daily use are sheen-moisture and/or styling sprays including oils and/or silicones.
Cationic ingredients are often used to provide conditioning benefits and are essential components for a conditioning treatment. Cetrimonium chloride is cost efficient and commonly used in economical conditioning formulations. Significantly more efficient is behentrimonium chloride, which provides outstanding conditioning properties such as improved wet and dry combability and wet feel.
Dialkylquats, such as distearyldimonium chloride and dicetyldimonium chloride, contain two long hydrocarbon chains and are more hydrophobic in nature than the monoalkyl quats such as cetrimonium chloride. Due to their hydrophobizing property, proven by a curl retention test, they impart anti-frizz properties, which are essential for ethnic hair. Due to sustainability concerns and the environmental impact of products, biodegradable esterquats are becoming more popular.
Distearoylethyl dimonium chloride is not only more eco-friendly and economical, it is nearly as efficient in conditioning as behentrimonium chloride.
Cationics’ conditioning properties can be further optimized by combining the cationics with silicone-based conditioners, which often shows a synergistic effect. Among the silicone-based conditioners, silicone quaternium-22 is a very efficient T-structured silicone quat, which can be applied in both intensive conditioners and shampoos. In combination with an organic quat like cetrimonium chloride, it improves synergistically the combability and feel of hair from a conditioner. The same effect can be found out of a shampoo in combination with a cationic polymer, such as Polyquaternium-10 or cationic guar.2
Additionally, as shown by a repeated combing study, silicone quaternium-22 can increase the survivor rate of hair fibers from the impact of combing and reduces significantly the tendency and amount of fiber breakage caused by repeated combing3. It also provides a 40% protection of the hair from damage caused by heat, such as a flattening iron.
Even more efficient is the higher molecular weight silicone T-quat, applied in a microemulsion, Silicone Quaternium-22 ME (INCI: Silicone quaternium-22 (and) polyglyceryl-3 caprate (and) dipropylene glycol (and) cocamidopropyl betaine).4 It provides even stronger heat protection (>70%) against flattening iron treatment and better color retention while further enhancing the already outstanding conditioning properties of the lower molecular weight silicone quaternium-22. The microemulsion form enables it to be used for crystal clear shampoos and for conditioning treatments.
Due to the homogeneous distribution of the silicone, an outstanding conditioning effect can be achieved at relatively low usage levels. In combination with cationics like cetrimonium chloride and in combination with a cationic polymers, such as polyquaternium-10 or cationic guar, it provides a synergistic conditioning effect in shampoos. Amino-functional silicones are the biggest group of organo-modified silicones used in personal care. The amino group is protonated and becomes cationic at acidic pH value normally used for shampoo and conditioner formulation. It enables substantivity and improved deposition. Evonik Industries has recently launched two new amino-functional silicones with different molecular weight for cost efficient and reproducible conditioning effects out of shampoos and conditioning emulsions. Both products are 100% active in liquid form with relatively low viscosity and thus easy to process. The higher molecular weight aminopropyl dimethicone is optimized for conditioning emulsions, the lower molecular weight one for crystal clear shampoos. Both types are very efficient in improving combability and feel of hair. Also the synergistic effects for combinations with cationics in hair conditioners and with cationic polymers in shampoos have been demonstrated.
In addition to protecting hair from damages by chemical/relaxer, heat/flattening iron and mechanical/grooming treatment, safeguarding hair from the damaging UV rays of daily sunlight exposure is an additional important need. Polysilicone-19 is a silicone UV quat containing side chains with either cationic groups or methoxycinnamic acid, a UV chromophore. Therefore, polysilicone-19 combines substantivity to hair with UV-absorbing properties. The effect can also be demonstrated after a rinse-off treatment such as shampooing or conditioning. Including polysilicone-19 provides 40% protection against damage by UV light after a conditioning rinse treatment. Table 1 summarizes the benefits of the conditioning agents for ethnic hair care. Table 2 gives an overview of the specific benefits of the described organo-modified silicones for shampoos. All are clearly soluble in surfactant based systems.
Hair Repair & Strengthening
Creatine is an amino acid derivative, naturally produced in the human body. As a small zwitterionic molecule, it is able to increase the number of electrostatic bonds/interactions within the hair shaft, which leads to an increase of hair’s tensile strength. Consequently, creatine significantly increases the mechanical strength of straightened ethnic hair. The repair efficacy is superior to hydrolyzed proteins. The tensile strength measurements were conducted with ethnic hair which had been straightened by guanidinium carbonate/Ca(OH)2.
An efficient leave-in treatment is often a vital regimen for ethnic consumers to maintain an esthetically attractive and healthy hair. Depending on the choice of ingredients, it provides benefits such as improving managability, providing moisturization, shine and frizz control and styling properties. It can be used daily when necessary, especially in between the cleansing steps with a shampoo in order to achieve desired properties such as frizz control. The guideline leave-in hair dressing cream formula is a water-in-oil emulsion with intense conditioning properties to provide manageability, gloss and some straightening effect.
Summary and Outlook
Hair breakage is the number one concern among the ethnic consumers. Aside from the unique inherited hair structure, another significant characteristic of ethnic hair is the dryness of the hair and scalp which causes a wide array of negative consequences. The dry hair has a rough surface and feel with dull appearance, tends to frizz, is prone to tangle and fragile. Therefore, it is important to avoid stripping out natural oils, or at least using products that can compensate for the loss of natural oils. Deep conditioning is important, especially among consumers with heat- or chemically straightened hair and/or permanently colored hair. Shampoo and conditioners as well as maintenance products for ethnic hair must contain richer caring and moisturizing ingredients in comparison to products for consumers with normal or oily hair. As the natural hair trend continues, sales of relaxer kits are expected to decline, while styling or setting products that aid in the manageability and styling of kinky hair will increase.
Healthier, stronger hair with high sensorial benefits will be a main target for consumer products. Looking ahead, the market will continue to develop new interesting products with innovative solutions that meet the special needs of each consumer.
More info: www.evonik.com/personal-care
- Mintel reports, Mintel Group Ltd.
- S. Herrwerth, I. Ulrich-Brehm, U. Kortemeier, P. Winter, M. Ferenz, B. Grüning, Silicone Quaternium-22: New Silicone Technology for Premium Hair Conditioning with Additional Benefits, SOFW, 2009, 6, 11-18
- T. A. Evans, K. Park, B. Yang, M. Kadir, S. Herrwerth, B. Grüning, Quantifying the benefits of conditioning treatments on hair breakage, SPC, 2010 (November), 51-54
- U. Kortemeier, C.Hartung, P.Winter, S.Herrwerth, P.Schwab, Silicone Quaternium-22 Microemulsion: Easy-To-Use Silicone Quat Technology for Premium Conditioning and Hair Protecting Benefits, SOFW, 2012, 4, 16-23 email@example.com