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Hair, Scalp and Gender

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This presentation covered the key differences (or otherwise) between hair fibres and scalp for men and women. Specifically, it reveals that most fibre differences are the result of treatments (bleaching, straightening, dying), not gender per se. Furthermore, it is proposed that men’s scalps are weaker and greasier than those of women. As a result of these difference, men are more prone to dandruff than women.
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GRAHAM TURNER, CBIOL, FRSB
Hair, Scalp and Gender
UNILEVER RESEARCH & DEVELOPMENT
Declaring and Disclosing Conflict of Interest
Name of the speaker: Graham A.Turner
Presentation title:
I have an affiliation (financial or otherwise) with a pharmaceutical, medical device,
or communications organization.
If yes, Details :
Paid employee of Unilever plc
Hair is the ultimate personal beauty
tool of self-expression
4
Cuticle
Cortex
Cortical cell
Macrofibril
Microfibril
Keratin
coiled-coil
Cortex - 80%
Major part of fibre mass in human hair
1-6mm thick and approx. 100mm long
Human hair contains only one type of cortical cell
Cells contain fibrillar (crystalline - 60%)
and non-fibrillar (amorphous - 30%) protein
Cortex made up almost entirely of keratin
Cuticle - 20%
Hair fibre composition and structure
Fibre structure
5
Hair shape and ethnicity
Hair fibres grow differently in ethnic groups. However, no gender differences
Observed within ethnic groups.
6
Hair diameter and gender
Optimum approach to measure fibre diameter is with a
laser scanning micrometer (takes cross section into account).
Most published reports do NOT apply such rigour.
Conflicting results. No clear difference with gender.
Indian population. Trend to increased diameter and degree of medullation in males (Gaur et al, 2007)
Females had higher Hair Area (HA) than males between ages 50-69 (Srettabunjong et al, 2016).
Used microscopy to measure hair diameter.
Defined Hair Area (HA) as: minor diameter x major diameter x 𝜋
4
But: Somali (Pacini et al, 1984) and Indian males (Das-Chaudhuri and Chopra, 1984) had thicker hair
(racial differences?)
7
Hair physical properties
Bending Torsion
Tension
Men
Women
Significance
Hair Break Force
(
mN)
Erik et al, 2007
664±268 752±223 N.S. (p=0.067)
Young’s Modulus
(Nm
-2)
Johri
& Jatar, 1982
0.1962 0.2303 N.S.
Cystine
/Cysteine
content
Clay et al, 1940
Men>Women
Significant
Males and females have different scalp needs
8
2%
4%
5%
8%
10%
15%
Less dry scalp
Less sensitive scalp
Less greasy scalp
Less greasy
Less itchy scalp
Less dandruff
3%
7%
9%
12%
16%
24%
Less dry scalp
Less sensitive scalp
Less greasy scalp
Less greasy
Less itchy scalp
Less dandruff
Unilever H&A studies: All respondents Brazil (1002), Turkey (989), Russia (1010), India (3208), China (2006), Indonesia
(1224), Japan (1127)
Globally, men experience more issues with scalp health than women
Scalp Needs and Concerns
Male and female scalps are different
9
Men lose more protein than women
Men more prone to dandruff Scalp sebum levels were higher
in males than in females (1.5
times greasier than females)
Female Male
100
200
300
400
500
600
0
Total protein (μg)
0
50
100
150
200
250
Female Male
Mean sebum
Unilever Clinical studies: BKK-BIO-GEN and SW-DDF-08-001
Male and female scalps are different
10
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
Men Women
Ceramide (µg/µg protein)
* Meta-analysis from 4 Unilever studies in Bangkok, 2003-2005
Antidandruff benefit
(TWHS reduction)
Men have lower ceramide levels in SC of scalp (weaker SC barrier; higher TEWL)
Weaker barrier makes men more prone to dandruff
Men have a greater response to antidandruff shampoo
(Clear AD Shampoo, 1% zinc pyrithione) *
11
Hair Growth and Gender
Linear Hair Growth Rate (LHGR) faster for women than men for all but the thickest hair (≥60µm)
-(Van Neste & Rushton, 2016)
In balding men , LHGR decreases.
In females with FPHL, LHGR decreases only for the finer hairs.
Hair Loss
12
The most obvious difference between
men and women is in the area of
androgenetic alopecia
Incidence is higher in men and starts
at much younger age (some in early
20’s)
FPHL is often accredited to post-
menopause (6% of women under age
of 50; 38% in women aged >70)
Messenger et al (2001)
Savin Scale of
Female Pattern Hair Loss
Hamilton-Norwood Scale of
Male Pattern Hair Loss
Causes Effects
Environment Tactile
Increasing Damage Severity
Process Look
Chemical Structural
- Pollution
- Sunlight
- Combing / brushing
- Hair Drying
- Heat Styling
-Straightening /
waving
-Colouring /
bleaching
-Weakness / Fragility
-Breakage -Split ends
- Dry feel
- Tangling
- Roughness
- Loss of movement
- Frizz
Hair treatment habits and damage
Hair damage
14
Healthy hair Cuticle starts to
break down
Cuticle disappears &
Cortex is exposed
Split ends appear Hair breaks
Hair Damage Characteristics
15
Physical damage
Chemical damage
Mechanism for fibre degradation is differentiated for physical and chemical processes
Summary
Presentation Title | Section Title 16
There are no major gender differences in hair fibre structure or physical properties
Hair styling and treatments result in more damage to the fibre (mainly an issue with women)
Women have a faster LHGR than men.
Males and females have different scalp needs
Men report more dandruff, itch and “grease” (sebum)
Men have weaker scalp SC barrier (lower ceramide and “extractable” protein)
Men respond more positively to antidandruff treatment (ZPTO)
Acknowledgements
Presentation Title | Section Title 17
Unilever R&D Port Sunlight
Fiona Baines
Jane Matheson
Jennifer Yates
Joe Muscat
Unilever R&D Shanghai
Echo Pi
Marina Bian
... Studies have demonstrated sex-related differences in a number of skin properties that might be expected to impact dandruff formation and treatment, such as stratum corneum hydration and skin barrier function as measured by transepidermal water loss [10]. In addition, there may be differences in hair washing and styling methods between males and females that could influence dandruff development [11]. A previous meta-analysis found no sex-related difference in the efficacy of ZnPT treatment [12]; however, the authors did not consider the relative contribution of detergency from non-anti-dandruff (AD) shampoo versus ZnPT shampoo. ...
Article
Full-text available
Objective Sex‐related differences in skin properties may be expected to impact on dandruff formation and treatment. A meta‐analysis approach was undertaken to investigate potential differences between males and females in response to zinc pyrithione (ZnPT) treatment versus non‐anti‐dandruff (AD) shampoo. A separate pooled statistical analysis of ceramide and total protein loss endpoints was also undertaken to assess potential sex‐related differences in stratum corneum properties that might influence response to ZnPT versus non‐AD shampoo in subjects with dandruff. Methods The meta‐analysis approach included data from 17 half‐head, double‐blind, randomized studies (N=2088) undertaken in Asia to assess the effectiveness of 1% ZnPT shampoo and/or non‐AD shampoo in reducing dandruff severity, as assessed by Total Weighted Head Score Adherent Flake (TWHS‐AF) methodology. Treatment duration was 4 weeks, with TWHS‐AF measured at weekly intervals. Data from an additional three studies (N=143) conducted in Asia were included in the pooled analysis of ceramide levels and protein loss from scalp skin of subjects with dandruff. Results Response to 1% ZnPT versus non‐AD shampoo was greater in males than in females at all time points; after 4 weeks, the between‐treatment difference in TWHS‐AF was −17.5 (95% confidence interval [CI] −19.5, −15.5) in males and −11.1 (−13.2, −8.9) in females. Sex‐related differences were observed between males and females in response to both 1% ZnPT and non‐AD shampoos. Males had a stronger response than females to treatment with 1% ZnPT shampoo, while dandruff decreased to a greater extent in females than in males when using non‐AD shampoo. Statistically significant sex‐related differences in ceramide levels and total protein loss were observed (both P<0.01). Ceramide levels were 0.76 times lower (95% CI 0.60, 0.97) in males than in females, while total protein loss was 1.4 times greater (95% CI 1.1, 1.9) in males than in females. Conclusion Males show a greater response than females to 1% ZnPT shampoo, while females show a greater response than males to non‐AD shampoo. These findings may in part be explained by the sex‐related differences observed in stratum corneum properties, which may make males more prone to dandruff than females. This article is protected by copyright. All rights reserved.
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