Impact of Shaving and Anti

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Impact of shaving and anti-perspirant use on the

axillary vault

G. A. Turner*, A. E. Moore, V. P. J. Marti*, S. E. Paterson* and A. G. James

*Unilever Research & Development Port Sunlight, Quarry Road East, Bebington, Merseyside CH63 3JW, U.K. and

Unilever Colworth, Colworth House, Sharnbrook, Bedford MK44 1LQ, U.K.

Received 6 October 2006, Accepted 11 November 2006

Keywords: anti-perspirant, axilla, inflammation, shaving, stratum corneum

Synopsis

Shaving the axilla is a regular part of the personal

care regime for many women in Europe, North

and South America. To assess the impact of sha-

ving on underarm skin, a series of investigations

were carried out, in which the thickness of the

axillary vault and fossa were measured using opti-

cal coherence tomography (OCT), and underarm

shaving debris was collected for study. The

response of the axilla to histamine iontophoresis

was also investigated. Additionally, a study was

carried out to investigate the impact of a novel

anti-perspirant roll-on formulation on irritationand self-perceived sensory properties of the axilla.

The results clearly demonstrate that shaving the

underarm consistently removes skin (stratum cor-

neum) as well as axillary hair (with a mean value

of 36.1% of the debris being skin). OCT measure-

ments demonstrated that in shaved areas of the

axilla, epidermal thickness is higher than in

unshaved areas. In response to histamine, wheal

and flare were both found to be greater in the

shaved axilla, when compared with an unshaved

control, but flare in the fossa was greater than

that in the vault. On the basis of these results, we

propose that the axillary vault has adapted to fre-

quent shaving, notably by the development of a

thickened epidermis. However, this adaptation is

often not sufficient to fully protect the axilla from

damage and irritation resulting from hair removal

(shaving). In these instances, we have demonstra-

ted that use of a novel anti-perspirant roll-on for-

mulation containing glycerol and sunflower seed

oil was able to reduce the impact of shaving-

induced irritation and improve self-assessment of

axillary condition.

Ré sumé

Pour beaucoup de femmes en Europe, en Améri-

que Latine et du Nord, se raser l’aisselle fait partie

intégrale du régime de soins personels. Pour évalu-

er l’impacte du rasage sur la peau de l’aisselle,

une serie d’études a été faite dans lesquelles ont

été mesurées l’épaisseur épidermale de la voûte

(region pileuse) et de la fosse (region non-pileuse)

par la tomographie optique (OCT), et la collection

du débris du rasage axilliaire, effectuée. L’effet sur

l’aiselle de l’iontophorèse d’histamine a aussi été

étudiée. De plus, une étude fut faite pour intéroger

l’impacte d’une nouvelle formule anti-transpirante

roll-on, sur l’irritation et la perception de la

condition de l’aisselle. Les résultats démontrent

clairement que l’action de raser l’aisselle enlève

non-seulement les poils de l’aisselle, mais aussi de

la peau (stratum corneum) (en moyenne 36.1%

du debris de rasage étant de la peau). Les mesures

OCT démontrent qu’aux endroits rasés de l’aisselle,

l’épaisseur épidermale est plus élevée qu’aux

endroits non-rasés. En presence d’histamine,

Correspondence: G. A. Turner, Unilever Research & Deve-

lopment Port Sunlight, Quarry Road East, Bebington,

Merseyside CH63 3JW, U.K. Tel.: +44 151 641 3705;

fax: +44 151 641 1861; e-mail: graham.turner@

unilever.com

Presented at the IFSCC World Wide Wellness Conference,

Florence, 2005 and AAD 64th Annual Meeting, San

Francisco, 2006.

International Journal of Cosmetic Science, 2007, 2 9, 31–38

ª 2007 The authors. Journal compilation

ª 2007 Society of Cosmetic Scientists and the Socié té Française de Cosmétologie 31


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l’inflamation et l’étandue de rougeur sont accentu-

és dans les endroits rasés de l’aisselle par rapport

aux endroits non-rasés, mais la rougeur est plus

accentué dans la fosse que dans la voûte. En se ba-

sant sur ces résultats, nous supposons que la voûte

axiliaire s’est habitué au régime de rasage fré-quent, notament par le dévelopment d’un épi-

derme épaissi. Cependant, cette adaptation est

souvent insuffisante pour protéger l’aisselle entière-

ment contre l’irritation causée par l’élimination de

poils (rasage). Dans cet éventualité, nous avons

démontré que l’utilisation d’une nouvelle formule

anti-transpirante roll-on contenant du glycerol et

de l’huile de tournesol était capable de réduire

l’impacte de l’irritation causée par le rasage et

améliorer la perception de la condition axilliaire.

Introduction

The surface layer of skin, the stratum corneum, is

comprised of several layers of flattened, keratin-

filled corneocytes. These cells are continuously

shed from the skin surface and the process is nor-

mally imperceptible. Shed corneocytes are replaced

by new ones in a manner that is highly coordina-

ted with cell loss at the skin surface. The corneo-

cytes are embedded in a lipid matrix, and together

they form an effective barrier to both transepider-

mal water loss and entry of potentially harmful

substances. Despite this important function, the

stratum corneum is not the same throughout thebody, with modifications occurring as a result of

the different stresses imposed upon different body

sites, the most obvious difference being the num-

ber of cell layers found within the corneum [1].

Investigation of the stratum corneum of the axil-

lary region has revealed reduced barrier function

and modified levels and ratios of epidermal barrier

lipids [2]. The personal care regime of many

women in the Western hemisphere often includes

application of an anti-perspirant or deodorant

product (to control sweat and malodour produc-

tion) and shaving to remove axillary hair. Shaving

of the axilla is often accompanied by visible and/or

sensory irritation, due to skin damage [3]. Artifi-

cial removal of the surface layers of skin, for

example by shaving, can lead to dry flaky skin [4].

This is due to the cell differentiation process being

perturbed, and the consequent arrival of immature

corneocytes at the skin surface. Shaving can also

cause irritation due to physical damage (cuts/

nicks), and therefore the natural barrier to irri-

tants is impaired. Historical data from studies on

male facial shaving has revealed that up to 20%

of the material removed during a shave is skin [5].

Irritation of the axilla is both uncomfortable and

unsightly. As anti-perspirant use is an almost ubi-

quitous part of personal hygiene behaviour, weconsidered that this product form would allow us

to reduce the impact of shaving on irritation, or

reduce the signs of shaving-induced irritation. Our

approach was to develop formulations capable of

delivering cosmetically acceptable materials to the

axilla with the potential to improve skin condition

and reduce irritation. Glycerol is well known to

aid hydration of the stratum corneum [6], while

topical application of sunflower seed oil (a source

of linoleic acid) has been demonstrated to promote

the repair of epidermal barrier function [7]. We

thus formulated an oil-in-water emulsion anti-

perspirant product suitable for use in a roll-on dis-

penser containing a combination of glycerol and

sunflower seed oil.

The aim of the studies reported in this paper

was to determine to what extent shaving of the

female underarm can damage the skin and investi-

gate the potential for a novel anti-perspirant roll-

on to prevent this damage.

Experimental

Assessment of shaving debris

Six female volunteers were each supplied with a

disposable razor (BiC Classic LadyTM, Bic UK Ltd.,

South Harefield, UK), and a pot containing 15 mL

70% (v/v) isopropanol. Study instructions, for the

test shave, were to wait 1–3 days since the previ-

ous axillary shave, and to wash off underarm

products using soap or shower gel immediately

beforehand. Volunteers were asked to test shave at

home, exactly as normal, but to dip the razor into

the pot of 70% (v/v) isopropanol after each stroke,

and also to rinse it in tap water before re-applying

to the axilla. On collection, shaving debris from

both left and right axillae were pooled to give

maximum sample size. Each sample was gently

centrifuged for 5 min at 1000 rpm in a graduated

tube, and enough supernatant removed to leave a

volume of 0.5 mL, including the pellet. The quan-

tity of sample collected dictated that weight would

be the most suitable method to measure the skin

and hair fractions. This was essentially the liquid

transfer method described by Elden [1], who in the


ª 2007 Society of Cosmetic Scientists and the Société Française de Cosmétologie, 29, 31–3832

Impact of shaving and anti-perspirant use on the axillary vault G.A. Turner et al.


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same study, also showed a good correlation

between the volume and weight methods of meas-

urement. For each sample, approximately 50 lL of

the suspension was applied to a microscope slide,

which was then covered and sealed. Examination

of the slides took place under phase contrast (No-marski) settings.

Epidermal thickness

The epidermal thickness of volunteers was meas-

ured using optical coherence tomography (OCT),

with a SkinDex 300 OCT scanner (Isis Optronics

GmbH, Mannheim, Germany). Eight female sub-

jects (aged 25–45) and eight male subjects (aged

32–52) participated in this phase of the study.

Measurements were taken from the axillary vault

(central, hairy region), axillary fossa (region sur-

rounding the vault), face, upper chest and volar

forearm of female volunteers, and from the beard

(shaved) and non-beard (unshaved) regions of the

faces of male volunteers. Female subjects were

asked to shave their underarms 24 h before OCT

measurements were made. Male subjects were

asked to shave their faces as per their usual rout-

ine. Three images were captured from each site.

Thickness of viable epidermis was measured using

the ruler option in the OCT Vision software. Mean

epidermal thickness was determined by averaging

15 rulers from the three images.

Iontophoresis

Histamine iontophoresis was carried out in the

vault and fossa of both axillae of nine volunteers

(eight females and one male). Subjects were asked

to shave both axillae 2 days prior to the study and

apply no underarm product on the day of the

study. One axilla (randomized to left or right) was

shaved immediately prior to iontophoresis in both

vault and fossa. The intention was to ensure that

the fossa region of the axilla was also shaved, even

though this is not a normal event. A sterile solu-

tion of 1% histamine dihydrochloride in a 2.5%

methyl cellulose hydrogel was delivered into the

skin using an electric current supplied by an iont-

ophoresis controller (Moor Instruments Ltd,

Axminster, U.K.). Blood flow was measured using

a dual-chamber laser Doppler flow monitor (Moor

Instruments Ltd). Baseline flux (blood flow) meas-

urements were monitored for 1 min, followed by a

50 lA electric current for 10 s, followed by a fur-

ther monitoring for 5 min. On removal of the

chambers, transparent film was placed over the

area and the size of wheal and flare were recor-

ded.

Axillary clinical assessment

Thirty female volunteers, aged 18–55 years, were

recruited for this two-phase protocol. The initial

provocation phase consisted of daily underarm

shaving and exaggerated application (four times

per day) of a control anti-perspirant roll-on appli-

cation (Table I). When a visual irritation score of

1.0 ± 0.5 was reached in both underarms (by day

8 of the provocation phase), the subjects moved

into the test phase of the study. Upon commence-

ment of the test phase, subjects were provided

with two coded anti-perspirant roll-on formula-

tions (test and control, Table I), each labelled for

use under the left or right underarm. Product

application site was randomly assigned. The test

phase consisted of twice-weekly underarm shaving

(reflecting normal shaving frequency; Wednesday

and Saturday evenings) and exaggerated product

application (four times daily). Irritation was

assessed visually by an expert assessor three times

per week (Monday, Wednesday and Friday) during

the morning visit to the test centre, prior to the

first product application of the day, for a test per-

iod of 4 weeks. The degree of irritation was

assessed using a 0- to 3.5-point visual scale(Table II). At the end of each test week, subjects

were asked to complete a forced-choice question-

naire probing skin attributes such as ‘soft’,

‘smooth’ and ‘less irritated’.

Statistical analyses

Differences in epidermal thickness between body

sites and shaved/unshaved sites were analysed

Table I. Major chemical constituents of the anti-perspir-

ant roll-on formulations used in the study

Formulation Ingredients

Test Water, aluminium chlorohydrate (17.5% w/w),

glycerine (4% w/w), sunflower seed oil

(4% w/w), Steareth-2, Steareth-20, fragrance

Control Water, aluminium chlorohydrate (17.5% w/w),

Steareth-2, Steareth-20, fragrance


ª 2007 Society of Cosmetic Scientists and the Société Françai se de Cosmétologie, 2 9, 31–38 33



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using ANOVA and paired comparison of least

square means using the Student’s t-test. Student’s

t-test was used to analyse the difference in both

flare and wheal following iontophoresis of hista-

mine. Axillary irritation scores were analysed

using repeated measures ANOVA. The Wilcoxon

sign rank test was employed to analyse cumula-

tive irritation scores and sensory questionnaire

data were analysed using Cochran–Mantel–Ha-

enszel statistics for row scores. Differences were

considered to be significant if the P-value was

£0.05.

Results and discussion

Shaving debris

The total weight of material collected for each

shaving sample ranged from 1.0 to 22.8 mg,

with an average of 7.4 ± 8.2 mg (mean ± SD).

The proportion of this fractionated out as skin

ranged from 9.3 to 64.4% w/w, with an average

of 36.1 ± 21.7% w/w (mean ± SD) in the six

shaving samples (Table III). A few examples of

the hair fractions were examined microscopically.

Some skin cells (corneocytes) were evident, as

was the occasional fabric fibre; however, as

expected, the bulk of these fractions were made

up of hair fragments, mostly coarse in nature,

and including a few small fragments sliced across

the hair shaft (see Fig. 1 for example images).

Microscopic visualization of the corneocyte frac-

tions confirmed that these were composed mostly

of skin, with a few hair fragments apparent (see

Fig. 2 for example images). From the results of

this study, it is clear that skin (stratum corneum)

is consistently removed from the axilla during

shaving. The proportion of skin relative to hair

was variable and depended on the amount of

hair present. This is a similar finding to that

reported previously for the shaving debris of the

male beard area [1], and provides clear evidence

of potential damage to the axillary stratum cor-

neum by the shaving process.

Epidermal thickness

Measurement of epidermal thickness using OCT

revealed that the lower, outer leg was significantly

thicker than all other body sites investigated

(P < 0.0001). Cheek, volar forearm and axillary

vault epidermis were not significantly different.

However, the vault area of the axilla was signifi-

cantly thicker than the fossa (P < 0.0001). Results

are presented graphically in Fig. 3. Data generated

on the male panel showed that the epidermis of

the beard area is significantly (P < 0.05) thicker

Table II Axillary irritation grading scale

Grade Description

0.0 No apparent cutaneous involvement

0.5 Faint, barely perceptible erythema or slight dryness1.0 Faint but definite erythema, no eruptions or broken skin or no erythema but definite dryness; may have epidermal fissuring

1.5 Well defined erythema or faint erythema with definite dryness, may have epidermal fissuring

2.0 Moderate erythema, may have very few papules or deep fissures, moderate to severe erythema in the cracks

2.5 Moderate erythema with barely perceptible oedema or severe erythema not involving a significant portion of the patch

(halo effect around the edges), may have a few papules or moderate to severe erythema

3.0 Severe erythema (beet redness), may have generalized papules or moderate to severe erythema with slight oedema

(edges well defined by raising)

3.5 Moderate to severe erythema with moderate oedema (confined to patch area) or moderate to severe erythema with

isolated eschar formations or vesicles

Table III Range in total weight of shaving debris collec-

ted, and relative percentage of skin and hair, with mean

(±SD) values

Volunteer

Total shaving

debris (mg)

Hair

(% w/w)

Skin

(% w/w)

1 1.32 35.6 64.4

2 1.03 49.5 50.5

3 8.83 50.6 49.4

4 3.19 74.3 25.7

5 22.76 82.6 17.4

6 7.56 90.7 9.3

Mean ± SD 7.44 ± 8.16 63.9 ± 21.7 36.1 ± 21.7





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than that of the non-beard area (Fig. 4). The

increased epidermal thickness of shaved areas

(female axillary vault and male beard area) may

be the result of a frequently occurring cascade of

shaving-induced pro-inflammatory mediators, lead-

ing to chronic hyperproliferation, and hence local

thickening, in order to facilitate repair of the bar-

rier, or provide enhanced protection from subse-

quent shaving events. Such localized thickening

need not be accompanied by overt signs of inflam-

mation such as erythema.

Iontophoresis

Histamine iontophoresis of the axillary vault and

fossa resulted in an increase in both flare (Fig. 5)

and wheal (Fig. 6) in the shaved axilla when com-

pared with the respective unshaved control. Previ-

ous studies have indicated that shaving of axillary

skin can damage the epidermal barrier [4], while

shaved skin has been demonstrated to respond

with increased itch and erythema following iont-

ophoretic delivery of histamine [3]. The present

Figure 1 Phase contrast microscopeimages of representative shaving

debris hair fractions. Magnification

for both images is ·10.

Figure 2 Phase contrast microscope images of representative shaving debris skin fractions. Focusing the microscope

through the layers revealed the clump in the lighter picture on the left to be made up of corneocytes, although this is

less clear from a single image. The picture on the right shows a single corneocyte and a cluster of about three together.

Magnification for both images is ·40.

80

60

40

A v e r a g e e p i d e r m a l t h i c k n e s s ( µ m ) , n = 8

20 45 48

49 53 54 55 55

59

0Rightchest

Leftaxillaryfossa

Rightaxillaryfossa

Rightaxillaryvault

Rightcheek

Right leg

Body site

Leftaxillaryvault

Rightforearm

Figure 3 Average epidermal thick-

ness for different body sites (eight

female subjects), measured using a

SkinDex 300 OCT scanner. Three

images were captured from each sit-

e, and the thickness of viable epider-

mis measured using the ruler option

in the OCT Vision software.





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results provide further evidence of this increased

sensitivity to histamine in shaved skin. However,

the flare in the fossa was significantly greater than

that observed in the vault (P < 0.05), when both

of these sites were shaved (wheal was also greater,

although not significantly). As discussed above,

the vault region of the axilla has a thicker epider-

mis than the fossa, which we have proposed is due

to a hyperproliferative response to regular shaving.However, such shaving is not a normal occurrence

for the axillary fossa, and the thicker epidermis in

the vault may explain the histamine iontophoresis

observation, i.e. it is more resistant than the fossa

to penetration of histamine. In the unshaved sites,

no difference in histamine iontophoresis was found

between vault and fossa.

Axillary clinical assessment of an anti-perspirant

formulation

The improvement in axillary irritation following a

provocation phase to induce erythema in the axilla

is shown in Fig. 7. The irritation observed in this

study was largely redness (erythema), although

the dryness data followed the same trends as that

recorded for redness, but with lower incidence and

severity. The irritation observed at the end of the

run-in phase (day 1 in Fig. 7) was well balanced

between underarms assigned to test and control

treatments. In the experimental phase, the test

roll-on shows statistically significant superiority

(P £ 0.05) to the control formulation from day 3

(the first assessment point in the test phase). The

test formulation (containing glycerol and sun-flower seed oil) showed a decrease in visual irrita-

tion over the 29 days of the experimental phase of

the study, while the control roll-on maintained

essentially the starting level of irritation.

Figure 4 Average epidermal thickness of cheek (eight

male subjects), measured using a SkinDex 300 OCT scan-

ner. Three images were captured from each site, and the

thickness of viable epidermis measured using the ruler

option in the OCT Vision software.

16.00 Flare

*

*n =914.0012.0010.00

F l a r e s i z e ( c m

2 )

8.006.004.002.000.00

Vault

*denotes P


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Cumulative mean irritation is shown in Fig. 8.

The differences in cumulative visible inflammation

significantly favour the test roll-on from day 5

onwards. Cumulative 29-day visible inflammation

exhibits a split of 27 : 2 in favour of panellists

scoring test anti-perspirant roll-on lower than thecontrol, compared with those with control lower

than test (P < 0.001).

The output from the sensory questionnaire,

completed by the panellists at the end of each

week, was aggregated over the 4 weeks of the

study as there was no evidence of a consistent

change in this data over the weekly data sets.

Analysis of the combined data for rating underarm

skin shows that the underarm treated with the test

formulation scored better for all attributes (Soft,

Smooth, Supple, Comfortable, Healthy, Moistur-

ized, Cared For, Less Irritated and Less Sore). All

these differences were significant at greater than

the 95% confidence level (Fig. 9).

Conclusions

The present study has provided evidence that

shaving of the axilla results in removal of skin,

as well as hair. Previous studies have indicated

that shaving can result in an increased potential

for irritation and itch. This study has provided

evidence that the removal of surface layers of

skin cells may be a contributory factor in the

increased irritation and itch potential of the axil-la. Furthermore, we have shown that the shaved

area of the axilla, the vault, has a thicker epider-

mis than the unshaved area, the fossa. The

response to histamine iontophoresis in the shaved

axilla was greater than that of the unshaved

(both flare and wheal), providing a further exam-

ple of the potential for shaving to damage the

epidermal barrier. Histamine response in the

vault of the shaved axilla was less than that in

the shaved fossa, which is proposed to be due to

the thicker epidermis in the vault affording some

degree of protection from the shaving process.

We also postulate that this increase in thickness

of vault epidermis is due to regular shaving of

this area of the underarm causing chronic dam-

age, and setting off a cascade of pro-inflammatory

mediators. This in turn results in hyperprolifera-

tion of the keratinocytes and development of a

thicker epidermis. As shaving the underarm is

such a fundamental part of the hygiene regime

for women, and because deodorant/anti-perspir-

ant use is near-universal, we have developed anew roll-on anti-perspirant containing glycerol

and sunflower seed oil as skin benefit agents. The

present study provides a clear demonstration that

this combination in an anti-perspirant roll-on can

alleviate shaving-induced irritation. Furthermore,

the results of a self-administered questionnaire

clearly show that this improvement in irritation

is accompanied by a general perception of being

‘softer’, ‘smoother’, ‘healthier’, etc., all valuable

attributes for a cosmetic product such as an anti-

perspirant.

Acknowledgements

The authors would like to thank Dr Carol Vin-

cent (Unilever R&D, Trumbull, CT, U.S.A.) for

assistance in the OCT studies. We would also like

to acknowledge Mrs Gail Brennan (Unilever R&D

Port Sunlight, Merseyside, U.K.) for expert clinical

evaluation and supervision of axillary clinical stu-

dies.

16

Test Control

12

8

C u m u l a t i v e

i r r i t a t i o n

s c o r e

4

00 5 10

Days into test phase15 20 25

Figure 8 Cumulative visible irritation with use of a test

roll-on anti-perspirant containing glycerol and sunflower

seed oil, vs. a control formulation. Initial irritation test

was generated using an exaggerated shaving and prod-

uct-use protocol in the run-in phase.

Figure 9 Self-assessment of axillary sensory attributes.

All attributes for the underarm treated with the test for-

mulation (containing glycerol and sunflower seed oil)

were significantly different (P < 0.05) when compared

with the control.





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