Hair care – damage limitation

Hair care technology may not have been the most dynamic area for development in the last year but it is a hugely important sector of the cosmetics industry. Here John Woodruff focuses on issues raised at the 2010 IFSCC congress and current ingredients that address them

Despite products for hair being a worldwide multi-billion dollar industry patent activity over the last 12 months has been relatively quiet. A quick search for hair product compositions granted in the US shows less than 25, of which nearly half are for hair colouring formulations. At the 26th IFSCC congress 2010, held in Buenos Aires in September this year, there were only six podium and two poster presentations where hair was the main topic.

The power of protection

The causes of hair damage and ways to mitigate this were the subject of the paper by Mike Fenwick^[1] who said that healthy hair has a smooth outer cuticle layer that protects the inner cortex and gives hair shine, feel and influences combability whereas the cortex gives hair its elasticity and strength. Treatments like bleaching, perming, permanent straightening by relaxing or transient straightening by usage of a flat iron all damage the hair structure and repeated use leads to a loss of lustre, weakening and hair breakage as well as impaired manageability. Compositions for hair care may offer protection against damage or the repair of damaged hair.

Protective hair care actives can either be applied directly with the treatments that cause the damage or the hair may be treated with a formulation containing the protecting active before the damaging process starts. An example of the latter is a pre-treatment conditioner that claims heat protection prior to thermal styling.

Hair care actives with repair efficacy can either be incorporated in wash-off formulations like shampoos or conditioners or for more intense treatment they can be applied from a leave-in formula or a styling product. Overall there is a broad variety of different hair damages and a plethora of different possibilities for protection or repair combating the negative effects of these treatments.

Fenwick and his team studied the extent of damage caused by various treatments and then looked at the positive effect of adding hydrolysed wheat peptides, creatine and a guanidine derivative to the treatment compositions. The study by Fenwick showed that different styling technologies lead to different kinds of hair damage, which have differing impacts on the cosmetic performance of hair, like shine, manageability or breakage. While bleaching shows the most pronounced effect on the hair surface, perming and relaxing affected both the cuticle and cortex. Thermal stress and damage by UV radiation attacked mainly the inner structure of the hair.

Creatine showed the strongest efficacy in repair of bleached hair and protection against perming damage. The guanidine derivative showed significant protection against the disruptive effects of straightening and flat ironing as well as repair activity in permed hair and both substances had a superior activity profile compared to hydrolysed wheat peptides.

Reducing thermal damage as a result of hot flat ironing was also the subject of the paper by Y Zhou^[2]. This type of styling appliance can exceed temperatures of 200°C and is a major cause of damage to hair keratin. Thermal treatment of hair causes the conversion of the helical protein to the β-sheet conformation and protein loss also occurs. Thermal damage also leads to hair breakage through combing stresses. Polymer pre-treatment consists of an insulating or sacrificial layer on the hair that provides surface protection and the morphological improvement in cuticle integrity and smoothness which the polymer imparts plays an important role in its anti-breakage effect. Zhou found that selected polymer pre-treatments such as polyquaternium-55 and VP/acrylates/lauryl methacrylate copolymer prior to the use of hot flat ironing provides protection against keratin thermal degradation and reduces hair breakage by as much as 55%.

Moisture management

Dry hair is a common complaint and various technologies exist for improving its moisture content. A method described by Y Mineo^[3] at the IFSCC was the use of cationic multi-lamellar vesicles (CCMV) as a delivery system for cholesterol. Mineo said cholesterol exists inside hair fibre as an internal lipid and plays a crucial role in the hair’s moisturising ability. However, ageing and permanent wave treatments cause a loss of cholesterol and lead to reduced hair moisture content.

The CCMV were formed from the double-chained ester quat, dipalmitoylethyl hydroxyethylmonium methosulfate. It has ester bonds in its lipophilic moiety and the vesicles formed have a high penetration capability. Cholesterol was encapsulated within the vesicles and the penetration and moisturising capacity of the system measured. It was found that the vesicles were quickly and strongly adsorbed to hair and that 2.8% penetrated into the cortex.

Colour creativity

Although a considerable proportion of new patents relate to hair colouring procedures there was only one podium presentation at this year’s congress on the subject. This was given by Ebato Atsuko who described a system for colouring grey hair using melanin^[4]. Melanin is a natural black pigment existing in human hair but it is too large to penetrate the hair shaft so cannot be used directly as a dyestuff for hair colouring. In biological processes, melanin is generated from the amino acid tyrosine by oxidation and polymerisation reactions of oxidative enzymes, such as tyrosinase. There are some intermediates, called melanin precursors, generated in the course of melanin formation. These molecules are useful for dyestuffs because their size is small enough for hair penetration.

Atsuko presented a new bioconversion process using Aspergillus tyrosinase for production of 5,6-dihydroxyindole (DHI), a melanin precursor, which is readily converted to melanin by air oxidation without enzymes or other catalysts. This technology is different from conventional oxidative hair dye, said Atsuko. It is free from hydrogen peroxide and genuine natural shades are achieved. At first the hair dye is applied to grey hair and the melanin precursor penetrates into the cuticle where it rapidly converts to melanin by air oxidation. Grey hair is slightly coloured by the melanin formed and by repeating the cycle of treatments grey hair becomes gradually darker. Three to five repeated treatments make grey hair recover to naturally dark shades.

Ingredients in action

Ways to improve hair colouring or to make it last longer are the subject of ongoing research, whether it is the utilising of yogurt (see patents, p78) to improve colour deposition or more conventional methods based on silicone technology like Reactive Complex P from Biosil Technologies. Reactive Complex P is an ingredient formed from the reaction of panthenol with highly reactive methyl polysiloxane, designed specifically for either a delivery system for natural hair pigments or a colour locking system for colour treated hair. Its principal ingredients are dimethiconol, isolaureth-6, PEG-8 dimethicone and silicone quaternium-2 panthenol succinate and it is claimed to add long lasting hair colour while contributing hair bounce, manageability, vitality, shine, combability and softness.

Reactive Complex P is said to combine the moisturising and volumising benefits of panthenol, which penetrates readily into hair, with the polymerisation benefits of a reactive silicone, which crosslinks with keratin making it highly substantive. This crosslink cannot be washed off yet it does not crosslink to itself, thus causing no build-up. Because of this crosslink, colour can be delivered onto the hair shaft or locked onto the hair shaft to optimise the duration of the colour treatment.

Epiprotectyl UV from Rovi is a multi-component material that includes the UV filters octocrylene and butyl methoxydibenzoylmethane, which forms a protective film around the hair shaft. Other components include inulin lauryl carbamate, caprylic/capric triglyceride, behentrimonium chloride and sucrose laurate and it is applied at 10% in the form of a conditioning emulsion. The cationic behentrimonium chloride ensures strong adsorption to the hair surface, ensuring maximum protection from the UV filters.

ChromAveil from Croda is a methoxycinnamic diester quat with the INCI name Polyquaternium-95. It offers UVA and UVB protection from the damaging effects caused by exposure to sunlight for natural and dyed hair. A detailed brochure from Croda describes the various tests that show ChromAveil inhibits colour fade and improves the tensile strength of human hair.

Croda manufactures a wide range of cosmetic proteins derived from a variety of plant and vegetable raw materials including keratin, silk, elastin and collagen. One specific range of cosmetic hydrolysed proteins is the amino acid complexes, which are hygroscopic and exhibit powerful moisture binding properties. Due to their low average weight they are able to penetrate the hair cuticle and stratum corneum to moisturise from within. Amino acid complexes are substantive to both hair and skin. Studies using radio-labelling techniques show that these complexes when applied to hair are highly penetrative, both from simple aqueous systems and finished hair care formulations. Typically between 80-99% of the substantive complexes have been found inside the hair fibre, which makes them ideal moisturising ingredients in both leave-on and rinse-off hair and skin care products.

The results of hair substantivity and penetration tests conducted on Hydrotriticum WAA by Croda show that more than 95% of the substantive wheat amino acids penetrated into the hair shafts, with only 1-4% found on the surface of the hair. Total substantivity values are considerably higher from a conditioner base than from shampoo, which correlates with previous experience with conditioner and shampoo systems.

Prodew 500 from Ajinomoto is a mixture of sodium PCa with sodium lactate and a synergistic combination of amino acids, which is almost identical to the composition found in hair and skin. This is claimed to improve colour retention of semi-permanent dyes and to increase the tensile strength of the hair shaft. It also adds moisture to hair and improves smoothness, combability and shine. Also from Ajinomoto and based on amino acid technology is the cationic surfactant CAE [INCI: PCA ethyl cocoyl arginate], a natural Ecocert certified alternative to triclosan.

Blue Seakale HC from Biotech Marine comprises 18 amino acids and a number of minerals and polyphenols extracted from the marine algae, Crambe maritima (sea kale). When added at 1% to a simple conditioner formula this is shown to provide protection against colour fade and protects the hair during thermal styling processes by forming a protective film around the hair shaft. For application via a colouring shampoo the same company suggests Inula HC, an extract of Inula chrithmoide that improves colour take-up of cationic dyes and protects the hair from colour loss at the rinsing stage. It also contains the ceramide precursor glucolipids, which is said to improve cell cohesion, thus adding strength to the hair shaft.

Amino acids are a popular additive for hair products because of their film-forming and moisturising properties. Rahn supplies l-arginine and Phytocos supplies a multi-amino acid mixture obtained by hydrolysing proteins from peas, Pisum sativum. Phytocos also supplies hydrolysed proteins of Chenopodium quinoa, Panicum miliaceum (millet) and Hordeum vulgare (barley), which are also rich in a number of amino acids and mineral salts. Variati supplies Sericin B, which comprises amino acids obtained by hydrolysis of raw silk, which is principally composed of the proteins sericin and fibroin.

A silk protein derivative from Seiwa Kasei is Protesil LH [INCI: Hydrolysed silk PG-propyl methylsilanediol crosspolymer]. The hydrolysed silk protein part of the molecule is adsorbed onto keratin sites damaged by chemical processing and the silicone and alkyl groups form a hydrophobic film on the hair surface. It is said to improve the water resistance of hair, making it less liable to colour fade, to give a silky smooth feel to the shaft and to seal in moisture.

Hydrolysed Moringa oleifera seed extracts are the basis for Kelimor from Kelisema, a seed protein hydrolysate obtained by enzymatic action, which yields a high level of free amino acids and short chain peptides. It forms a protective film and its high substantivity on hair makes it especially suitable for cleansing and reparative hair products. It also imparts body and volume to hair and reduces surfactant irritancy of detergent formulations.

Besides the materials described at the IFSCC congress there are numerous others that claim to protect or repair hair during and after various treatments. Pellicer from Chesham Speciality Ingredients is sodium dilauramidoglutamide lysine, a gemini surfactant with a small molecular size that penetrates into the hair shaft. It is added to shampoos and conditioners where it repairs and smooths damaged cuticles and improves hair strength, thickness and water content and it may be added to pre-perming compositions to minimise chemical damage. The brochure contains numerous and impressive photomicrographs of its effect on hair when added to various compositions at 0.01% and 0.1% solids content.

Volume & condition

Adding volume to hair is often a requirement for functional shampoos and conditioners. Aquadew SPA-30 [INCI: Sodium polyaspartate] from Ajinomoto is claimed to be an effective moisturiser, to decrease static charge and to increase hair volume when added to shampoos and conditioners. Also from Ajinomoto, Eldew PS-203 [INCI: Phytosteryl/octyldodecyl/

lauroyl glutamate] forms lamella liquid crystals identical to ceramide structures and is a substantive moisturiser for skin and hair and is said to repair hair damaged by chemical processing.

Frequent washing with harsh shampoos also damages hair and there is a trend towards mild ones that are more suitable for daily use. Those based on olive oil are part of this trend and Kalichem supplies a number including Olive Oil Surfactant containing potassium olivoyl hydrolysed wheat protein; Olivoil Avenate Surfactant based on potassium olivoyl hydrolysed oat protein and Olivoil Glutamate Surfactant, which is sodium olivoyl glutamate. Also derived from olive oil are the Olivem products from B&T. Olivem 460 is an anionic surfactant derived from olive oil fatty acids [INCI: PEG-7 olive oil carboxylate]. Although anionic, it has a non-ionic behaviour and is very mild with good foaming properties. Olivem 300 [INCI: Olive oil PEG-7 esters] is said to be suitable for mild shampoos to provide emolliency and a pleasant feel after rinsing. It also acts as a co-solubiliser for fragrance and oils.

The water-dispersible emollients PEG-75 shea butter glycerides and PEG-70 mango glycerides are available from AAK and are used to add moisturising properties and conditioning activity to shampoos. Another material based on shea butter from AAK is Lipex Shea Betaine. This gives anti-static action and substantivity to hair, therefore improving hair volume and combing properties, and acts as a rheology modifier as it helps control product consistency and creates a stable creamy foam.

Hair care ingredients from natural sources are in as much demand as those for skin care. Beraca suggest its hair care system based on Passiflora edulis seed oil with Oryza sativa rice bran oil and Euterpe oleracea pulp oil. It claims that anthocyanins obtained from Euterpe oleracea pulp oil exert a powerful natural antioxidant effect that provides protection against environmental damage. Gamma oryzanol obtained from rice bran oil is also a strong antioxidant and omega-6 present in Passiflora edulis seed oil imparts protecting and moisturising benefits. It is recommended as an additive at 2% to provide moisturising properties, shine and texture in a variety of hair care products aimed at treating dry and damaged hair.

Cationic conditioning aids from natural sources seem unlikely but Emulsense from Inolex claims to be just that. By combining L-isoleucine, an essential amino acid derived from the fermentation of non-GMO rice, with a long chain fatty group derived from the oil of a brassica plant Inolex has created a material that comprises 65% of the cationic ingredient brassicyl isoleucinate esylate and 35% brassica alcohol that is certified natural by Ecocert. Various grades suitable for hair conditioning are available with optimised ratios of the cationic brassicyl isoleucinate esylate and fatty alcohol fractions and it appears to improve colour fastness and hair volume as well as adding shine and easy combing properties to the hair.

Missing from this feature are the many silicone compounds that are in so much use today in every aspect of hair care. So ubiquitous are they that they will be the subject of their own feature in a future issue of SPC.

Anti-ageing hair care
While ISP Vincience is renowned for its innovative skin care ingredients it is now building on this experience for hair as, just like ageing skin, ageing hair becomes thinner and weaker. The company has introduced BioHAIRapy, a line of three intelligent, functional ingredients designed to target key components of the hair follicle. Corn extract Capauxein is said to enhance cell signalling and communication, help improve hair vitality and optimise hair growth requirements. Yeast extract Dynagen targets the more mechanical properties of hair, enhancing the expression of proteins involved in the inner architecture of hair. And rice extract Protectagen is said to boost markers of stem cell activity and help natural defence against UV induced damage. These are described as new possibilities offering long-term real benefits for hair as well as immediate impact. There are said to be definite opportunities for leave-on conditioner and styling products, and ISP is also looking at whether the properties could be incorporated into rinse-off applications. The company is also working on hair pigmentation.

Author
John Woodruff www.creative-developments.co.uk

References
1. Farwick M et al, Characterization of different types of hair damages - strategies for prevention and repair, IFSCC Congress (2010)
2. Zhou Y et al, Investigation of thermal damage of hair from hot flat ironing and the thermal protective effects of cosmetic pretreatments, IFSCC Congress (2010)
3. Mineo Y et al, The injection system of cholesterol as a hair moisturizer, IFSCC Congress (2010)
4. Atsuko E., What if you could get recovered gray hair with real melanin? - a novel natural coloring system for gray hair using biological melanin precursors, IFSCC Congress (2010)

NB The suppliers of all the ingredients named in this feature have supplied efficacy data to the author and identified the material, or if a mixture its principal constituents, by INCI name but those interested should ensure that they validate the data before use.