skin training 2
TRANSCRIPT
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SKIN CARE
TRAINING
Alain KHAIAT, Ph. D.Vice President R&D Asia Pacific
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TRAINING CONTENT
Skin physiology Cosmetic functions:
mechanism
ingredients used
performance assessment
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Skin
Is the external barrier of the body, both
physical and immunological
Is the mirror of the state of health of thebody
Skin plays an essential role both in the
aesthetic and health field.
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SKIN PHYSIOLOGY
The skin is the outer most layer of the body. It
is constituted of 2 layers :
epidermis
dermis
which sit on the fat layer around the muscles.
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EPIDERMIS
The stratum corneum made essentially of
dead cells is exfoliating.
The space between the cells constitutes theintercellular cement.
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DERMIS
The dermis is where the collagen and elastin
fibers are. These fibers are responsible for
the skin structure and elasticity.They are degraded by enzymes called
collagenase and elastase which belong to
the class of Matrix Metallo Proteases orMMP.
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OIL PRODUCTION
Oil is produced in the sebaceous gland ,
production is stimulated by hormones
Oil flows into the hair follicle then onto the
skin surface
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Oil Production
Normal hair follicle where sebum empties onto skin surfacethrough follicle opening
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COMEDONES
Whiteheads are closed comedones. Theobstructed follicle prevents oil flow andprovides an oil reservoir for bacterial
growth. They lead to inflammation Blackheads are open comedones (follicle
obstruction). The color is melanin and
oxidized lipids, not dirt. The content is firmand dilates the follicle, blackheads are notinflammatory
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COMEDONESWhiteheadsor closed comedones
stays beneath the skin. Slightly raised, lightcoloured lesion
Caused by build up of debris ( cells + sebum)
within follicle
Blackheads oropen comedones
a whitehead becomes a blackhead when
it enlarges until a dark plug protrudes through
the skin surface
* Both whiteheads and blackheads may stay
on the skin for a long time.
* Whiteheads and Blackheads are non-
inflammatory
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SOLAR SPECTRUM
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UVB DAMAGE
UVB impact on DNA in the cell creating
damages which may lead to cancer
P53 gene codes for a protein that allowsrepair of the DNA or kill the cell if repair is
not possible: sunburn cells
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UVA DAMAGE
UVA acts through an oxidative stress,
forming free radicals (reactive oxygen
species) that will damage the DNA Reactive oxygen species create damages
leading to cancer
Pigment production is the defensemechanism
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TRAINING CONTENT
Skin physiology
Cosmetic functions: mechanism
ingredients used
performance assessment
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COSMETICS
DEFINITION :
Products applied on the skin, hair, teeth or
teguments in order to : beautify
perfume
cleanse
promote attractiveness
alter the appearance
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COSMETICS : FUNCTIONS
Cleansing
Moisturizing
UV protection
Aging - Wrinkle
Acne & Oily skin
Pigmentation
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CLEANSING
Soap : high pH, low rinsability, high
irritation
Some soap have high rinsability, low irritation
Cream cleanser / Facial wash :
rinse off : detergent-based, neutral pH,
irritation depends on detergent type andconcentration
tissue off : leave on, emulsion-based, less
fresh clean feel
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RINSABILITY
Measured by Fourrier Transform Infra Red
or FTIR : scanning of the skin before
application and after rinsing of a cleanser.The difference is representative of the
quantity of product left on the skin.
Digital imaging with proper light allowsalso to evaluate rinsability
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IRRITATION
Patch test
Chromameter (red color)
Trans epidermal water loss : TEWL
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CLEANSER FORMULA
A typical cleanser formula consists of :
detergent 10 - 15 %
foam booster 0 - 2%
preservative < 1 %
fragrance 0 - 1%
water Qs 100 %
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CLEANSER FORMULA
Surfactants : usually combinations are used to
enhance lathering and reduce irritation. SLS is to
be avoided, it strips the skin of its lipids
contributing to irritation. Preservatives : allergy potential of formaldehyde
donors.
Fragrance : known allergens (like Peru BalsamorMuskAmbrette)have been banned. It is important
for the fragrance to meet IFRA guidelines
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MOISTURIZING
Water, like air or light, is essential to life
Moisturization is a womans main
expectation from a cosmetic product
Dermatologists face dry skin condition
every day : physiological, pathological(ichthyosis), therapeutic (PUVA, retinoids)
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WHERE IS THE WATER ?
50% is intracellular
15% is extracellular
5% is plasmatic
30% is in the sweat glands
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MECHANISMS OF REGULATION
Hydration through deeper layers
Loss through evaporation
Moisture retaining ability of the stratum
corneum,dependent on :
Hydro Lipido Proteic film (HLP)
Natural Moisturizing Factor (NMF)
integrity of intercellular cement
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HLP FILM
Originates from sebum and sweat secretions
Composed of :
water - triglycerides ions - cholesterol free & esterified
amino acids - squalene
urea - fatty acids
- waxes
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NMF
Amino acids
Urocanic acid
Pyrollidone carboxylic acid : PCA
Electrolytes
Sugars
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INTERCELLULAR CEMENT
Ceramides ( sphingolipides )
Fatty acids ( Linoleic acid )
Cholesterol ( free & esters )
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MOISTURIZING INGREDIENTS
Occlusive agents
Structural lipids
Hydrophilic film forming agents
Humectants
NMF
AHA
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OCCLUSIVE AGENTS
Vaseline, paraffin
Waxes of animal or plant origin
Some silicone oils or waxes
Some vegetable oil (sweet almond)
Some fatty esters (isopropyl myristate)
Fatty alcohols
older technique, often comedogenic
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STRUCTURAL LIPIDS
Essential Fatty Acids (EFA : linoleic,
linolenic acids)
Poly unsaturated fatty acids (PUFA : EPA,DHA)
Ceramides or pseudo ceramides
Cholesterol
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HYDROPHILIC FILM FORMING
AGENTS GAG : glycosaminoglycans like Hyaluronic
acid or chondroitin sulfates
Collagen
Proteins
Chitin or Chitosan
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HUMECTANTS
Glycerin
Propylene Glycol or Butylene Glycol
Sugars
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NMF
PCA
Urea (below 10 %)
Amino Acids or hydrolyzed protein
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AHA
At low concentration (< 2 % ) AHA are
moisturizing agents by creating hydrogen
bonds between the protein chains.The most common are :
glycolic acid
lactic acid citric acid
malic acid
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PERFORMANCE ASSESSMENT
FTIR :the ratio of amide I to amide II peaks is
function of the skin hydration
NMR : nuclear magnetic resonance
TEWL : trans epidermal water loss
Capacitance (Corneometer)
Conductance (Skicon)
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FORMULATION
Typically they are oil in water emulsions :
water
propylene glycol : penetration enhancer itbecomes irritating above 5%
humectants, film forming agents, AHA, NMF
emulsifiers : could contribute to irritation,concentration to be kept to a minimum
oils, fatty esters : some are comedogenic
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UV PROTECTION
Two types of filters are used :
chemical
mineral
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SOLAR SPECTRUM
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CHEMICAL FILTERS
Limited spectrum, highly regulated
Most common filters :
cinnamates (UVB)
PABA (UVB)
Oxybenzone (UVA)
Avobenzone (UVA)
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MINERAL FILTERS
Broad spectrum, filtering capacity function
of size, influence on product texture
Most common filters : TiO2
ZnO
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PERFORMANCE ASSESSEMENT
SPF measurement in vivo: it is the ratio of
the minimum erythemal dose with and
without protection ( relates only to UVBprotection )
in vitromeasurements :
Diffey method spectrophotometric absorption method
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AGING : INTRINSIC
Program theory : each cell contains a clock
which control the number of multiplication
Error theory : occurrence of errors in thereplication which eventually lead to cell
death
Control theory : cells function is remotelycontrolled by secretions ( hormones )
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AGING : EXTRINSIC
Sun : UVA / UVB / IR
Psycho social factors : overwork, stress
Dietary factors : insufficient water supply,vitamin deficiency, alcohol, smoking
Iatrogenic factors : corticosteroids,
ionizing radiation, diuretics Pathological factors : genodermatose,
acrogenia
Hormonal factor : menopause
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MANIFESTATIONS OF SKIN AGING
Epidermis :
reduction in cell renewal rate
thickening of stratum corneum decrease in barrier efficiency : increase in
TEWL and hyperkeratosis
ridges are flattened out and intercellular
spaces enlarged
pigmentation problems : actinic lentigines
decrease in skin immune system
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MANIFESTATIONS OF SKIN AGING
Sebaceous glands :
reduction in sebum secretion (hormones
influenced) Sweat glands :
less active
HLP film : thinning of film means less protective barrier
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MANIFESTATION OF SKIN AGING
Dermis :
destruction of collagen and elastin fibers
network proteoglycans and glycoproteins are reduced
increase in elastin synthesis : elastosis
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WRINKLES
Expression lines :
they are the first manifestation
due to constant creasing of the face accentuated by environmental factors
they appear around the eyes (crows feet), the
nose and mouth (naso-labial fold), forehead(frown lines)
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WRINKLES
Gravity lines :
skin and muscle structure become slack and
droops downwards subcutaneous tissues tend to sag
flabby cheeks, double chin, bags under the
eyes and drooping eyelids
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WRINKLES
Elastosis wrinkles :
due to UV radiation, the epidermis is injured
(free radicals), the fibroblasts in the dermisare over-active and abnormal deposits of
elastin occur
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ANTI AGING : PREVENTION
Protective agents :
sun protection
anti free radicals : SOD, Se, Si, Vit. E, Vit. C,carotenoids, flavonoids, -orizanol
Nourishing agents
vitamins : A (esters), B5 (panthenol), C, E, EFA(linoleic & linolenic acids), PUFA
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ANTI AGE : PREVENTION
Moisturizing agents
Metabolism activators :
unsaponifiable lipids (phytosterols)
plant extracts (Centella asiatica, Ginseng)
microalgae extracts
Bacteria, fungal or yeast extracts
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ANTI AGING : PREVENTION
Conditioning agents :
anti MMP (elastase, collagenase)
hyaluronic acid collagen, elastin (hydrolyzed)
nucleic acids (DNA, RNA)
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ANTI AGING : REPARATION
Retinol : transformed into the skin inretinoic acid, it has its positive propertieswithout the irritation
AHAs work by reducing the corneocytescohesion, increasing desquamation (cellrenewal), hydration and plasticity
Vitamin C
micro circulation activators : plant extracts
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PERFORMANCE ASSESSMENT
Cutaneous relief :
imprint techniques : micro depressionary
network, profilometry macrophotography : visible, UV light
confocal microscopy
biopsy Cell renewal :
use of a dye : danzyl chloride or dihydroxy
acetone (DHA)
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PERFORMANCE ASSESSEMENT
Alternative methods :
used to determine the activity of ingredients
on molecules, cell cultures or skin replica Physiological parameters :
hydration
elasticity : cutometry, twistometry,balistometry
pigmentation : photography, chromameter
vascularisation : Laser Doppler Velocimetry
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COSMETIC ACNE: from physiology
to treatment
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ACNE
95% of the population is affected at one
time or another by ACNE
ACNE affects 85% of the teenagers: 10% require medical attention: severe acne
with 1% difficult to treat
90% have mild acne or cosmetic acne
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Puberty : period over which thesecondary sexual characters gradually
become manifest as the reproductive
system develops to full capacity and
there is rapid somatic growth.
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Onset of puberty in girls
Breast development following the increase
of estrogen from the ovaries
Menstruation
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Puberty and Adolescence
Adolescence is a difficult period for most
people: period of changes
Herd bonding & sexual involvement
Adolescence is a particularly bad time to
have skin problems, especially on the faceor on the extremities
Physiological changes in the
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Physiological changes in theskin during puberty and
adolescence
Increase in sebum production: oily skinand hair
Onset of "body odor"
Anguish in young men when male-patternbalding begins in the teenage years
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Ideal skin for girls
Skin should be oil-free with no pimples or spots
Plenty of hair on head, but none on face, under thearms or on the legs
puberty makes this ideal image virtually
impossible to achieve
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Acne vulgaris (Pimples)
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Acne : a disorder of the pilosebaceous
unit, occurs in both sexes but is more
distressing to the women, not only
because of the cosmetic effect but
because of the frequent permanent
scarring
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ACNE
Normal hair follicle where sebum empties onto skin surfacethrough follicle opening
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Classification of acne
Non-inflammatory lesions: open & closed
comedones
Inflammatory lesions: papules, pustules,
nodules, cysts
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Pathogenesis of acne
Sebaceous glands hyper-activity
Pilosebaceous duct obstruction
Bacterial colonization and inflammation
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Increases sebum secretion
The cause of acne (1)
The effect of Androgen hormones
Im Androgen
Hyperkeratinization
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The cause of acne (2)
The effect of Propionobacterium acnes
We love
sebum Hydrolyzes sebum
Free fatty acids
Inflammatory acne
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ACNE TREATMENT
Drugs
Dermatological Procedures
Cosmetics
and/or
Squeeze the pimple
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DERMATOLOGICAL PROCEDURE
Peeling with drying and keratolytic agents : sulfur,
salicylic acid, resorcinol, benzoyl peroxide
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COSMETICS
Traditionally the anti-acne approach has
used drying keratolytic ingredients:
Benzoyl peroxide (5 or 10%) Salicylic acid (0.5 or 2%)
Sulfur (~2%)
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OILY SKIN
Ingredients usually used to reduce shine :
clay (bentonite)
talc Kaolin
These ingredients will increase oil production
Ingredients used to control oil secretion: Soy/Wheat protein
Cedarwood
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OILY SKIN
Efficacy is measured by :
Sebumeter : measure of the absorbance
of a tape Sebutape
removal of lipids and determination of
quantity
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PIGMENTATION
Melanins are the result of the
transformation of Tyrosine into DOPA then
Dopaquinone by Tyrosinase in themelanocyte.
Melanins are transferred from the
melanocyte to the keratinocyte layers
Pigmentation Formation Mechanism
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Tyrosinase
KERATINOCYTE
(Epidermis)
MELANOCYTE
(Basal Layer)
Tyrosine Melanin
Dermis
UVIrritation
Inflammatory Response
Hormone3
1
2
Melanosome
FIBROBLAST
Variety of Causes
Variety of Responses
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PIGMENTATION
Ingredients used to decrease pigmentation :
hydroquinone : effective but not safe
ascorbic acid derivatives plant extracts : Kojic acid, arbutin, Licorice,
Centella, Bayberryextract
Except for Hydroquinone, the skin lighteningeffect is only visible after several weeks.
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PIGMENTATION
Efficacy is measured by :
Chromameter : L measure
Mexameter : evaluation of melanin andredness
Photography : visible, UV with data analysis
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THANK YOU