Hair, Scalp and Gender

Abstract

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.

Full text

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