Specialist Hair Treatments PDF

Specialist haircare products Gabriela Daniels Hairdressing history Image from 1920s, UAL Archives 2 Lesson agenda Hair colouring Hair perming and relaxing: key differences Overview of the hair fibre properties vs chemical alterations Hair colour Du...

Specialist haircare products Gabriela Daniels Hairdressing history Image from 1920s, UAL Archives 2 Lesson agenda Hair colouring Hair perming and relaxing: key differences Overview of the hair fibre properties vs chemical alterations Hair colour Due to the presence of eumelanin and pheomelanin produced and deposited within the hair cortex during the anagen phase of the hair growth cycle by the melanocytes in the hair follicle (HF) The onset of hair greying is attributed to: cumulative oxidative damage to the melanocytes and their environment in the HF, various genetic factors, stress neuromodulators, nutrition, gene clock, however partial and temporary reversion has been demonstrated in some studies: Paus et al,. (2024) Human Hair Greying Revisited: Principles, Misconceptions, and Key Research Frontiers, Journal of Investigative Dermatology, 144 (3) 474 – 491. Hair colouring Three possible aims: to cover grey, to change existing colour, a combinations of the two The results can vary in longevity: Practical modern hair science (2015), Wicket and Evans, chapter Hair colouring by Jennifer Marsh p.119 Basics of hair bleaching Bleaching materials include: Part 1 Oxidising agent: H2O2 (6, 9 or 12%) In emulsion stabilised at acidic pH 2-5 (and chelating agents); Part 2 Alkaliser (Ammonium Hydroxide) cause cuticle swelling and rapid access of the oxidising agent, professional product contain other materials which cause more rapid reactions Parts 1 and 2 are mixed just before application, more recently persulfates are used as they have a complementary effect Thickened/creams are used in order to ensure that the oxidising product is applied to hair roots to minimise damage Hair must not be washed prior to bleaching to ensure that the protective lipids on the hair and scalp will reduce hair damage and scalp irritation Bleaching near the scalp is faster due to higher temperature due to proximity to the human skin, hence the technique to bleaching should take this into account Using acidic shampoos after bleaching reduces protein damage Hair colour lightening is necessary for colouring: most permanent colourants involve some degree of oxidation Boullon, C. and Wilkinson, J. (2005) The Science of Haircare, Taylor and Francis Group, USA p.248 Hair colourants: product types and modes of action Type Description of Chemistry and Effect Permanent Two component system (mixed just prior to use): (Oxidative dyes) 1) Alkaline (Ammonia) medium of small colourless dye precursors. (Level 3) 2) Hydrogen Peroxide (H2O2) (6% +) to oxidise dye precursors which react pH of typical to give large dye molecules that get trapped inside the hair. Time fo level 3 and 4 As sufficient strength H2O2 is used, hair lightening also occurs. colourants = Demi-Permanent Two component system as above but: 9.8-10.3 Or Tone-on-Tone - Monoethanolamine or Amino methyl propanol is used as alkaliser. (Oxidative dyes) - Only 2% or 3% H2O2 is used. (So no hair lightening, unless the hair is light, (Level 2) in which case it can lighten further). Penetration of dyes into hair not as great as with Permanents. Semi-Permanent Small, intensely coloured neutral dye molecules that penetrate to (Direct dyes) the cortex of the hair. AMP is included to cause swelling and aid dye diffusion (Level 1) (depth depends upon pH and hair porosity). Mix of dyes (adsorption rates). Temporary Large, intensely coloured ionic dye molecules that reside only on the (Level 0) hair surface. Dyes are only loosely bound to the hair. Progressive Lead Acetate + Sulphur or Silver Nitrate or Bismuth Citrate deposit in the hair - oxidise to form dark coloured metal-sulphides in the hair. Gradual build up effect from repetitive application. Hair colouring Hair dying can be dramatic or subtle 1883: p- phenylenediamine was discovered and the synthetic hair dye industry was born Currently: a positive dye list (EU) and world-wide scrutiny of dye safety ensure minimal dermatological and toxicological effects Oxidative hair dyes Always two-components which are mixed just prior to use. Colourless small dye precursor molecules in high pH medium penetrate the hair and are oxidised to highly coloured polymeric dye species that become trapped inside the hair. Colour Forming Reaction That Takes Place in The Hair: H2O2 + Primary Intermediate(s)* ----------> Reactive intermediate Reactive intermediate + Coupler(s)* ----------> Dye Molecules By using a combination of Primary Intermediate(s) and Coupler(s), variety of colours are formed. These colours are wash resistant. Typically, 2-5 intermediates and 2-5 couples are used. High pH is needed for: Swelling and cuticle lifting of the hair for good penetration of dye precursor molecules into the hair. Action of Hydrogen Peroxide in oxidising Primary Intermediates. Action of Hydrogen Peroxide in bleaching the hair for shades with lift. * Oxidative hair dye precursors are subject to regulations http://www.compoundchem.com/2015/05/14/hair-dyes/  Damage from bleaching The primary goal of bleaching: the oxidation of melanin, the products of this reaction are not characterised, but they would be colourless The follow secondary effects are UNDESIRABLE and weaken the hair: Impact on the cuticle: Oxidation of disulfide bonds in the cuticle to cysteic acid Increased hair hydrophilicity leading to increased water swelling which, in turn, enhances the penetration of surfactants Impact on the CMC: Removal of fatty acids and cholesterol bonded within the CMC, thus making hair more accessible to water Impact on the cortex: Oxidation of disulfide bonds in the KAPS to cysteic acid, thus destabilising the intermediate filaments (IF); weakening the cortical structure Hydrolisis of peptide bonds, produces soluble protein hydrolysates, easily washed and leaving the cortex more porous. Oxidation of disulfide bonds to cysteic acid Demi and semi-permanent hair dyes: direct dyes Molecules which are intrinsically coloured, no reactions take place Good colour palette of for mixing and achieving different shades Very intense/vibrant colours Formulated at pH 8.5 to 9.5 (with MEA) to temporarily increase the swelling of the hair and aid dye penetration and longevity. A cap is sometimes used - heat from the scalp enhances dye uptake. The dyes are usually formulated as „colour pairs‟: One small, one larger of the same colour to overcome unevenness in appearance between root and tip during wash fading. (Large molecules penetrate the more porous ends only and are more slowly washed out). Hair fibre and the dye molecules Temporary hair dyes Last one shampoo Strong vibrant colours Remain on the hair surface, but should not transfer to clothes via rubbing Cationic or anionic charges, the cationic dyes are strongly attracted to hair Used for temporary colouring or colour boosters following oxidative colouring Some Temporary „Basic‟ Hair Dyes Large cationic molecules that reside on the surface of hair. Substantivity allows them to be used in rinse-off products for subtle colouring effects. Some Temporary „Acid‟ Hair Dyes Large anionic molecules that reside on the surface of hair. No substantivity so are only used in leave-on product-types. Lesson agenda Hair colouring Hair perming and relaxing: similarities and differences Overview of the hair fibre properties vs chemical alterations Chemistry of hair perming (cold waving) Two-step process Reducing stage: Thioglycolic acid (TGA), formulated at pH 9 and above Glycerol thioglycolate (GTG), formulated at pH 7 (acid wave) whereby loose waves are achieved only Various studies, mostly in Japan, are looking into efficient and less damaging treatments Asian hair: larger diameter and round shape, temporary styling is less effective, hair strengthening and waving is more popular in the Far East Oxidation stage: H2O2 (c.2%)= at acidic pH The two components are formulated to be water thin and to be applied by sponge. The low viscosity is necessary to allow the actives to soak into hair as curled around the rollers. The process is less effective on bleached hair, and also may alters the effect of hair dyes  Chemistry of hair perming The hair fibres are under internal stress when wound Thiolate-catalysed onto the rollers thus the -S-S- disulfide exchange bonds are strained. 20% of the disulfide bonds are being broken in the hair in the The disulfide bonds Evans and Wickett, p.165 reducing step, about 80% rearrange to relieve of them form new the stress (exchange Most common reducing agent: Thioglycolic acid disulfide bonds places) Most common oxidising agent: H2O2 Hair perming The hair is shampooed and towel dried , then separated into strands and these are applied technique on the rollers under tension. Rollers’ diameter and the width of the hair strands shape the final curls. The reducing agent (thioglycolic acid) is applied liberally, so that all hair is moistened, however the scalp should be protected. Process time=5-20minutes, depending on the hair condition. A thorough rinsing is required after this stage. Neutralisation: fixing stage (H2O2). Ideally done is two steps. Application of 70% of the neutralising lotion on the rolled hair (5mins), followed by unrolling (without pulling) and applying the remaining neutraliser. All this should be followed by thorough rinsing. Lesson agenda Hair lightening: process, hair damage and repair Hair colourants: oxidative and non-oxidative colourants Hair perming and relaxing: key differences Overview of the hair fibre properties vs chemical alterations Hair straightening (relaxing) Aim: to reshape hair permanently Regrowth in 6 weeks requires a new treatment The shape is retained regardless of washing and other styling Hair straightening of mid curly hair: based the chemistry of permanent waving, but using thick formulations (creams) which hold the hair straight. Relaxing of very curly hair: based on treatment with strong alkali Oxidation of disulfide bonds Alkali At least 30-40% of S-S bonds are affected in order to achieve straight hair style The chemical reaction of proteins and the OH¯ creates a permanent bond (S-CH2) = lanthionine As S-S bonds are not reformed, the hair looses its elasticity Damage to the protein chains also occurs, leading to more extensive weakening of the hair Chemistry of hair relaxing Common alkaline agents: sodium (Na), potassium (K) or lithium (Li) hydroxide (OH) formulated in thick emulsions, in order to:  prevent spilling over scalp control the area of application aid the straightening process. Guanidine Hydroxide = less effective, but milder = often products are called texturisers Confusing terms used in the commerce: “lye relaxers” are NaOH based products, therefore none-lye relaxers may be containing KOH or LiOH. LiOH is particularly aggressive to scalp Hair relaxing technique Protective cream such as petrolatum is applied to the scalp first The alkaline cream is then applied to the hair with a spatula or brush, avoiding reapplication over hair that has been already straightened. Hair smoothing strand by strand is necessary (without stretching excessively). Thorough rinsing of the hair and scalp is carried out. Washing hair with neutralising shampoo follows (can be used several consecutive times). Summary of chemical treatments Currently, market data suggests that fewer consumers are interested in altering their hair colour or shape The trend is unlikely to persist as fashion and individuality drive frequent changes in physical appearance Less aggressive chemical treatments are being developed Scenario 1: identify treatments, their order and anticipated hair damage. Scenario 2: identify treatments, their order and anticipated hair damage. Current hair appearance: short hair, natural color Desired permanent change to hair style: completely straighten and dye dark brown/black Scenario 3: identify treatments, their order and anticipated hair damage. Current hair style: below shoulder length, naturally straight, bleached blond Desired permanent change to hair style: create wavy curls, colour peach blond