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Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - Clinical study

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Acetyl hexapeptide-3 has been used in anti-aging topical formulations aimed at improving skin appearance. However, few basic studies address its effects on epidermis and dermis, when vehiculated in topical formulations. Thus, the objective of this study was to determine the clinical efficacy of acetyl hexapeptide-3 using biophysical techniques. For this purpose, formulations with and without acetyl hexapeptide-3 were applied to the ventral forearm and the face area of forty female volunteers. Skin conditions were evaluated after 2 and 4-week long daily applications, by analyzing the stratum corneum water content and the skin mechanical properties, using three instruments, the Corneometer® CM 825, Cutometer®SEM 575 and Reviscometer®RV600. All formulations tested increased the stratum corneum water content in the face region, which remained constant until the end of the study. In contrast, only formulations containing acetyl hexapeptide-3 exhibit a significant effect on mechanical properties, by decreasing the anisotropy of the face skin. No significant effects were observed in viscoelasticity parameters. In conclusion, the effects of acetyl hexapeptide-3 on the anisotropy of face skin characterize the compound as an effective ingredient for improving conditions of the cutaneous tissue, when used in anti-aging cosmetic formulations. © 2015, Faculdade de Ciencias Farmaceuticas (Biblioteca). All rights reserved.
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*Correspondence: Patrícia M.B.G. Maia Campos. Faculdade de Ciên-
cias Farmacêuticas de Ribeirão Preto. Universidade de São Paulo. Av. do
Café, s/n, - Monte Alegre, 14040-903 - Ribeirão Preto, SP, Brazil. E-mail:
pmcampos@usp.br
Article
Brazilian Journal of
Pharmaceutical Sciences
vol. 51, n. 4, oct./dec., 2015
http://dx.doi.org/10.1590/S1984-82502015000400016
Acetyl hexapeptide-3 in a cosmetic formulation acts on skin
mechanical properties - clinical study
Kassandra Azevedo Tadini, Daiane Garcia Mercurio, Patrícia Maria Berardo Gonçalves Maia
Campos
*
Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
Acetyl hexapeptide-3 has been used in anti-aging topical formulations aimed at improving skin
appearance. However, few basic studies address its eects on epidermis and dermis, when vehiculated
in topical formulations. Thus, the objective of this study was to determine the clinical ecacy of acetyl
hexapeptide-3 using biophysical techniques. For this purpose, formulations with and without acetyl
hexapeptide-3 were applied to the ventral forearm and the face area of forty female volunteers. Skin
conditions were evaluated after 2 and 4-week long daily applications, by analyzing the stratum corneum
water content and the skin mechanical properties, using three instruments, the Corneometer® CM 825,
Cutometer
SEM 575 and Reviscometer
RV600. All formulations tested increased the stratum corneum
water content in the face region, which remained constant until the end of the study. In contrast, only
formulations containing acetyl hexapeptide-3 exhibit a signicant eect on mechanical properties,
by decreasing the anisotropy of the face skin. No signicant eects were observed in viscoelasticity
parameters. In conclusion, the eects of acetyl hexapeptide-3 on the anisotropy of face skin characterize
the compound as an eective ingredient for improving conditions of the cutaneous tissue, when used in
anti-aging cosmetic formulations.
Uniterms: Acetyl hexapeptide-3/use in cosmetic formulations. Acetyl hexapeptide-3/clinical ecacy.
Biophysical techniques. Anti-aging/cosmetics. Clinical ecacy. Cosmetics.
Acetil hexapeptídeo-3 tem sido utilizado como um ingrediente ativo em formulações tópicas
antienvelhecimento para a melhoria da aparência cutânea. No entanto, poucos estudos avaliam seus efeitos
na epiderme e derme, quando veiculado em formulações tópicas. Portanto, o objetivo desse estudo foi
a determinação da ecácia clínica de acetil hexapeptídeo-3 utilizando técnicas de biofísica e de análise
de imagem. Para tal, formulações contendo, ou não, acetil hexapeptídeo-3 foram aplicadas no antebraço
volar e na face de voluntárias. As condições cutâneas foram avaliadas após duas e quatro semanas de
aplicação diária das formulações, por meio da análise no conteúdo aquoso do estrato córneo e avaliação
das propriedades mecânicas da pele, utilizando os equipamentos Corneometer® CM 825, Cutometer
SEM
575 e Reviscometer
RV600. Todas as formulações avaliadas aumentaram o conteúdo aquoso do estrato
córneo na face, o qual permaneceu constante até o m do estudo. Por outro lado, somente as formulações
contendo acetil hexapeptídeo-3 apresentaram efeito signicativo nas propriedades mecânicas, por meio
da diminuição da anisotropia da pele na face. Não foram observados efeitos signicativos para os
parâmetros de viscoelasticidade. Em conclusão, os efeitos de acetil hexapeptídeo-3 na pele caracteriza
este peptídeo como um ingrediente ativo efetivo para a melhoria das condições cutâneas, quando utilizadas
em formulações cosméticas.
Unitermos: Acetil hexapeptídeo-3/uso em cosméticos. Acetil hexapeptídeo-3/eficácia clínica.
Antienvelhecimento/cosméticos. Cosméticos/formulação tópica/avaliação. Formulações tópicas/
antiidade.
K. A. Tadini, D. G. Mercurio, P. M. B. G. M. Campos
902
INTRODUCTION
In recent decades, cosmetic formulations have been
developed and employed in the treatment or prevention
of skin changes resulting from aging, such as loss of
elasticity, dryness, formation of wrinkles and spots, thus,
possible delaying invasive procedures such as plastic
surgery. In this context, substances with anti-aging action
have been proposed to delay the appearance of wrinkles
or leaving them less visible. However, due to the high
turnover in the cosmetic area, active substances and their
cosmetic products are constantly available to commercial
purposes without basic studies on the action mechanisms
supporting their benets (Hermanns-Lê et al., 2001).
The advances in the area of skin biology, such as the
mechanisms involved in cell renewal, in skin aging and
in the action of neuroendocrine receptors, have increased
peptide importance. The skin is a neuroendocrine immune
organ in which many different molecules operate in
an autocrine-paracrine manner to guarantee tissue
homeostatsis in physiological and pathophysiological
condition (Sivilia et al., 2008; Takema et al., 1994). Due to
their chemical structure, peptides may act in the hydration,
skin protection and homeostasis, keeping cutaneous tissue
healthy and with a young appearance.
On the other hand, the search in the dermatology area
for non-toxic molecules that mimic the action of botulinum
neurotoxin, has identified acetyl hexapeptide-3 in a
rational design program. An in vitro study demonstrated
that acetyl hexapeptide-3 inhibits neurotransmitter release
with a potency similar to that of botulinum neurotoxin,
although as expected, it displayed much lower ecacy
than the neurotoxin (Sivilia et al., 2008; Blanes-Mira et
al., 2002).
However, there are few hardcore data about the
eects of acetyl hexapeptíde-3 on epidermis and dermis,
when vehiculated in topical formulations, under actual
conditions of use, mainly using objective measurements,
which are an important tool in clinical ecacy studies.
It should be considered that knowledge about the
use of the acetyl hexapeptide-3 is just beginning and
much remains to be learned. Thus, it is very important to
elucidate the eects and prove the ecacy of this active
ingredient, which is commonly used to improve the skin
conditions because of the proposed antiaging activity. So,
clinical objective studies to assess acetyl hexapeptide-3
efficacy in the skin should rely on non-invasive skin
biophysical techniques, which are often used to evaluate
cosmetic products under actual conditions of use in human
skin (Haftek et al., 2008; Paye et al., 2007; Uhoda et al.,
2002).
Furthermore, the results should contribute to a
better understanding of the acetyl hexapeptide-3 eects
by three biophysical techniques, Corneometer® CM 825,
Cutometer
SEM 575 and Reviscometer
RV600, in terms
of skin hydration, skin elasticity and viscoelasticity, and
skin anisotropy, showing that the peptide is clinically
ecient and also that its use is very important in cosmetic
formulations, due to its antiaging eects.
In this context, the aim of this study was to determine
the real benets of acetyl hexapeptide-3 on human skin, by
analyzing the eects of a cosmetic formulation containing
this active substance in terms of stratum corneum water
content and skin mechanical properties.
MATERIAL AND METHODS
Test formulations
The vehicle formulation tested contained 3.5%
(w/w) C12-20 acid PEG-8 ester, 0.7% (w/w), acrylate
polymer, 2.5% (w/w) octyl octanoate, 2.0% (w/w)
propylene glycol, 2.0% (w/w) glycerin, 2.0% (w/w)
dimethicone DC 200/50CS, 7.5% (w/w) blend of
UVA/UVB sunscreen (fenilbenzimidazol sulfonic
acid, benzophenone-4) and 0.8% (w/w) blend of
parabens and phenoxyethanol, Phenonip
(Nipa Labs,
Wilmington, USA). The formulations were supplemented
or not with Argireline
(solution containing 0.05%
acetyl hexapeptide-3) to a concentration of 10%. Acetyl
hexapeptide-3 was kindly provided by Galena Química e
Farmacêutica Ltda, Campinas, Brazil.
Study protocol
The study was approved by the Faculty of
Pharmaceutical Sciences of Ribeirão Preto - USP Ethics
Committee (CEP/FCFRP 60/2005).
Forty healthy female subjects 35-55 years old having
skin Fitzpatrick types II, III and IV participated in this
study after having given their written informed consent.
Exclusion criteria were the presence of any dermatitis and/
or other skin or allergic disease and smoking. Volunteers
were instructed not to apply any topical products to the test
sites for 2 weeks before and during the study. The subjects
were allowed to wash normally, but not to use other skin
care products on their arms and face. They were asked to
avoid getting a sun tan, although the formulations applied
had sunscreens in their composition to avoid the eects of
daily exposure to UV radiation.
Prior to all measurements, subjects remained in
the room for at least 30 minutes in order to allow full
Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study
903
skin adaptation to room temperature (20 ± 2 ºC) and
humidity (45-60%). Applications sites were randomized
in order to minimize anatomic functional bias. The
hydration index was assessed using measurements
of capacitance (Corneometer
CM825; Courage &
Khazaka, Koeln, Germany) and the skin elasticity and
viscoelasticity by cutometry (Cutometer
SEM 575;
Courage & Khazaka) and by resonance running time
measurements (Reviscometer
RV600; Courage &
Khazaka). The skin properties were examined using a
standardized study protocol.
After the baseline measurements, the subjects were
instructed to apply 1.0 mL of the formulations with acetyl
hexapeptide-3 on the ventral region of one forearm and
the vehicle on the other forearm, twice daily. Half the
subjects applied the 1.0 mL of formulation containing
acetyl hexapeptide-3 on the full face and the other half,
the vehicle. Measurements on forearms and cheeks were
carried out 2 and 4 weeks after daily application, 10-15
hours after the last treatment. For the last measurement,
the formulations were applied in the evening and the
measurements were taken in the following day (Savica
et al., 2004).
Specifically, the experiment was conducted with
twenty volunteers who were divided in two groups:
Group 1: application of the vehicle in the left
forearm and in the face, and vehicle supplemented with
acetyl hexapeptide-3 in the right forearm.
Group 2: application of the vehicle supplemented
with acetyl hexapeptide-3 in the left forearm and in the
face, and of the vehicle in the right forearm.
Instrumentation
The stratum corneum water content was determined
with a non-invasive, skin capacitance meter (Corneometer
®
CM 825, Courage & Khazaka, Germany). The averaged
values of twenty measurements were used for subsequent
calculations (Dal’Belo, Gaspar, Maia Campos, 2006;
Fluhr, Gloor, Lazzerini, 1999; Fluhr et al., 1999).
Mechanical properties of the skin were determined
using two instruments, the Cutometer
SEM 575 (Courage
& Khazaka, Germany) and Reviscometer
RV600 (Courage
& Khazaka, Germany).
The measurement with Cutometer
SEM 575
consisted of five consecutive cycles of a 2 s suction
application period followed by a 2 s relaxation period.
The suction load was 450 mbars. The method analyzed the
following mechanical parameters: Ua/Uf, the ratio of total
retraction to total distension, called gross elasticity; Ur/Ue,
net-elasticity of the skin without viscous deformation; Uv/
Ue, the ratio of viscoelastic to elastic distension and Ur/
Uf, the ratio of immediate retraction to total distension,
called biological elasticity (Dobrev, 2000; Dobrev, 2002).
The Reviscometer
®
RV600 is an equipment based
on resonance running time measurements (RRTM) of
acoustical shockwaves (Takema et al., 1994; Hermanns-
et al. 2001; Ruvolo ; Stamatas ; Kollias, 2007). RRTM
measurements were taken in precise directions, according
to Uhoda et al.(2002), analyzing the medium RRTM, the
lowest and highest RRTM (RRTM max and RRTM min).
The anisotropy dened as the ratio between RRTM max
and RRTM min was calculated (Stamatas, Kollias, 2007).
Statistical analysis
Anisotropy calculated values were statistically
analysed using the Kruskal-Wallis test. The other data
showing a Gaussian distribution were evaluated by the
ANOVA test. The values obtained by the vehicle and
formulation with acetyl hexapeptide-3 after 4 weeks were
statistically analysed using Mann- Whitney test for non-
parametric distribution, and unpaired t- test for parametric
distribution. Dierences were accepted as statistically
signicant at p < 0.05.
RESULTS AND DISCUSSION
Acetyl hexapeptide-3 has been used in anti-aging
topical formulations due to its effects in improving
the skin appearance (Blanes-Mira et al., 2002; Zhang,
Falla, 2009). However there are few basic studies about
its effects on skin, as well as, about its mechanism
of action. In the present investigation, the efficacy
of dermocosmetic formulations containing acetyl
hexapeptide-3 was evaluated using biophysical techniques
and the capacity of two instruments, the Cutometer
SEM
575 and Reviscometer
RV600, to identify skin changes
was compared.
Cutometer
SEM 575 is a non-invasive skin-
elasticity meter that consists of a microprocessor-regulated
pneumatic system that applies suction via a 2-mm circular
opening in the handheld probe. Evaluation is based on
measurements of skin deformation in response to suction.
The Reviscometer
®
RV600 is a device equipped
with a probe containing two needle-like sensors. When
placed on the skin, one needle transmits ultrasound
shockwaves and the other is the recipient. The time needed
by waves to go from the transmitter to the recipient is the
measured RRTM parameter expressed in arbitrary units.
The resonance running time measurements (RRTM) of
acoustical shockwaves propagates differently through
K. A. Tadini, D. G. Mercurio, P. M. B. G. M. Campos
904
the skin according to the state of the elastic bers and its
moisture content (Takema et al., 1994; Hermanns-Lê et
al. 2001; Ruvolo, Stamatas, Kollias, 2007).
Age-related cutaneous changes, such as wrinkles and
skin laxity, are especially prominent on the facial skin, so
several studies have used this site to evaluate the ecacy
of cosmetic products (Takema et al., 1994; Sommerfeld,
2007). On the other hand, the ventral forearm, which
has limited exposure to sunlight and is an easier site for
measurements, has also been used to evaluate changes
characterizing chronological aging (Sumino et al., 2004).
In this study, both regions were used to evaluate the eects
of formulations with acetyl hexapeptide-3.
Four weeks after applying formulations on the
forearm skin, the stratum corneum water content showed
an increasing tendency, not statistically signicant, when
compared to the baseline values (Figure 1) (p > 0.05).
On the other hand, formulations with and without acetyl
hexapeptide-3 increased water content of the stratum
corneum in the face region (p < 0.01), which remained
constant until the end of the study (4 weeks) (Figure 1).
Thus, vehicle only also increased the stratum corneum
water content to appropriate levels of hydration in a normal
skin. These results are in line with previous data obtained
by this research group, when peptide-containing emulsions
were applied on the volunteers forearm skin once, and after
a 4-week period the emulsion with or without peptides
caused an enhanced skin hydration (Anconi, Campos,
2008). Skin hydration is an important parameter to
evaluate the ecacy of a substance. Moisturizing products
may prevent skin alterations resulting from aging and may
be used as support in the treatment of several skin diseases
(Rawlings, Harding, 2004).
Corneometer
®
CM 825 is a device which determines
the water content of supercial epidermal layers down to a
depth of about 0.1 mm and expresses the values obtained
in arbitrary units (Dal’Belo, Gaspar, Maia Campos, 2006;
Fluhr, Gloor, Lazzerini, 1999; Fluhr et al., 1999). Our
results showed that acetyl hexapeptide-3 did not increase
stratum corneum water content, compared to the vehicle.
The vehicle formulation is composed by emollients
that can act on superficial moisturizing and acetyl
hexapeptide-3 may eectively contribute to hydration of
deeper layers of epidermis, which is not measured by this
technique.
In the study of mechanical properties, we compared
the ability of two instruments, the Reviscometer
®
RVM600
and the Cutometer
®
SEM 575, to detect skin surface
mechanical changes.
Data on shear wave propagation, obtained by the
Reviscometer, are shown in Figures 2 to 5 and indicate
that acetyl hexapeptide-3 exhibits a signicant eect by
decreasing the anisotropy property of face skin. Compared
to the vehicle, this reduction was also signicant on the
face after 4 weeks (Figure 5B). Such a nding suggests
increased firmness or tensor effect, since the speed of
shear wave propagation on the skin surface is directly
proportional to its stiness (Ruvolo, Stamatas, Kollias,
2007; Vexler, Polyansky, Gorodetsky, 1999). In rigid
skin the time for wave spreading will be short, anisotropy
and RRTM values smaller (Nizet, Pierard-Franchimont,
Pierard, 2001; Verhaegen et al., 2010).
Ruvolo, Stamatas and Kollias (2007)
and Hermanns-
et al. (2001) observed that while the minimum RRTM
values remained fairly constant for the different age
groups, the maximum RRTM values increased with age.
FIGURE 1 - Skin stratum corneum water content before and after a 2 and 4-week long application of test formulations (vehicle,
vehicle + acetyl hexapeptide-3) on the forearm (A) and face area (B) of volunteers. AHP: acetyl hexapeptide-3. *Signicantly
dierent from the baseline values (p<0.01).
Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study
905
FIGURE 2 - Maximum RRTM before and after a 2 and 4-week long application of test formulations (vehicle, vehicle + acetyl
hexapeptide-3) on the forearm (A) and face area (B) of volunteers. AHP: acetyl hexapeptide-3.
FIGURE 3 - Minimum RRTM before and after a 2 and 4-week long application of the test formulations (vehicle, vehicle + acetyl
hexapeptide-3) on the forearm (A) and face area (B) of volunteers. AHP: acetyl hexapeptide-3.
FIGURE 4 - Medium RRTM before and after a 2 and 4-week long application of the test formulations (vehicle, vehicle + acetyl
hexapeptide-3) on the forearm (A) and face area (B) of volunteers. AHP: acetyl hexapeptide-3.
K. A. Tadini, D. G. Mercurio, P. M. B. G. M. Campos
906
Thus, anisotropy is dened as the ratio between maximum
and minimum RRTMs and will also increase with age.
In contrast, in this study, the mean, maximum and
minimum RRTM did not show alterations after treatment
with formulations tested, meaning that they were less
discriminatory between formulations when compared with
anisotropy values.
It is concluded that acetyl hexapeptide-3 is an
effective anti-aging compound as already mentioned
by Blanes-Mira et al. (2002). The author, using silicone
replicas, observed that topical application of an emulsion
containing the peptide attenuated the depth of wrinkles
in the periocular region after 30 days of treatment, when
compared with the vehicle.
Unlike the results on the face region, formulations
applied on the forearm did not cause any significant
change in the skin anisotropy, suggesting that the eects
of the cosmetic formulations in the two regions studied
are dierent, the same as occurred in the determination of
stratum corneum water content. This is due to the fact that
face and forearm skin have quite dierent characteristics.
The face is more vulnerable to photoaging than the forearms
and more susceptible to the action of antiaging products
(Blinchmann, Serup, 1988). According to Blinchmann and
Serup (1988) and Rogiers (1990), variations in the skin
characteristics in dierent regions of the body may also be
related to dierences in the stratum corneum thickness and
the number and activity of sebaceous glands.
Skin elasticity parameters were not significantly
altered, after a 4-week period of daily application of
formulations on both skin regions (Figures 6 and 7)
as indicated by the lack of changes in the Cutometer
®
-
measured elasticity index. Thus, it is possible to conclude
that the Reviscometer was better qualified to detect
statistically significant effects of acetyl hexapeptide-3
than the Cutometer. Paye et al. (2007)
also noted that
Reviscometer is able to better discriminate different
treatments than the Cutometer, in a study involving
induced slight xerotic skin conditions.
In a previous retinoids ecacy study of our research
group we observed that dermocosmetic formulations
containing retinoic acid altered the skin anisotropy after a
4-week period of daily applications, but these formulations
did not alter the cutometer parameters. However, after
a 8-week period of daily application, it was possible to
detect alterations not only in skin anisotropy but also in
cutometer parameters (Ua/Uf - the ratio of total retraction
to total distension and Ur/Uf - the ratio of immediate
retraction to total distension) (unpublished data). These
observations suggest that significant changes in skin
elasticity may occur later or these changes have to attain
a certain level to be detected by the Cutometer .
Finally, it is necessary to consider that loss of
skin elasticity is one of the main problems of aging
and this is a mechanical property inuenced by elastin,
which together with collagen and glycosaminoglycans
make up the connective tissue. As a large number of
events cause cutaneous aging
(Rieger, 1996), the use
of active ingredients that are able to induce alterations
in skin mechanical properties is a valid option for the
improvement of skin conditions. In this context, the eects
of acetyl hexapeptide-3 on the anisotropy of face skin,
FIGURE 5 - Anisotropy (RRTM
maximum
/ RRTM
minimum
) before and after a 2 and 4-week long application of the test formulations
(vehicle, vehicle + acetyl hexapeptide-3) on the forearm (A) and face area (B) of volunteers. AHP: acetyl hexapeptide-3.
*Signicantly dierent from baseline values; Signicantly dierent from Vehicle after 4 weeks using the formulations.
Acetyl hexapeptide-3 in a cosmetic formulation acts on skin mechanical properties - clinical study
907
characterizes the compound as an eective ingredient for
improving conditions of the cutaneous tissue, when used
in anti-aging cosmetic formulations.
CONCLUSIONS
In this study, acetyl hexapeptide-3 was found to
be an eective ingredient for use in anti-aging cosmetic
formulations due to its reduction of the anisotropy of face
skin and probable action on its mechanical properties.
This way, it can be used in cosmetic formulations to
prevent skin alterations, premature aging and improve
skin conditions.
DISCLOSURES
On behalf of all authors, the corresponding author
states that there is no conflict of interest. The authors
gratefully acknowledge the nancial support of São Paulo
Research Foundation (FAPESP).
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FIGURE 6 - Skin elasticity (Uv/Ue: ratio of delayed distension to immediate distension ) before and after a 2 and 4-week long
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Received for publication on 20
th
November 2014
Accepted for publication on 02
nd
July 2015
... O acetilhexapeptídeo-3 apresentou um efeito significativo na diminuição da anisotropia da pele da região da face em comparação ao placebo; na região interna do antebraço, não foi verificada diferença significativa, quando comparado ao placebo. Em relação à hidratação, tanto na região da face como no antebraço, não houve resultados estatisticamente significativos (30). ...
... Ao contrário da maioria dos trabalhos, Tadini e cols (2013) mostraram que a aplicação do acetilhexapeptídeo-3, na região interna do antebraço, não causou alteração significativa na pele, sugerindo que os efeitos das formulações cosméticas nas duas regiões estudadas são diferentes (30). Levando em consideração o fato de a pele da região da face, pescoço e colo é mais vulnerável ao fotoenvelhecimento do que a parte interna do antebraço, suas características são bastante diferentes. ...
... Esse ativo mostrou ser uma promissora alternativa ao uso da neurotoxina botulínica, vem sendo empregado em formulações antienvelhecimento, ganhando mercado entre os consumidores que optam por minimizar os efeitos das rugas sem intervenção invasiva (1,5,20,21,31). O acetilhexapeptídeo-3, é uma substância de baixo peso molecular, que foi sintetizada com objetivo de mimetizar os efeitos da neurotoxina botulínica, embora muito menos potente quando comparado a neurotoxina botulínica (14,(20)(21)(29)(30)(31). ...
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O envelhecimento é um processo multifatorial, resultado de diversos fatores, intrínsecos e extrínsecos. Consiste em um processo continuo que não afeta apenas a aparência, mas as diversas estruturas e funções da pele. Todo o organismo sofre com as alterações provocadas pelo envelhecimento, porém, é na face, uma das áreas mais foto exposta, que essas alterações são mais facilmente reconhecidas. A região facial envelhecida pode apresentar flacidez, rugas, linhas de expressão, entre outros distúrbios estéticos, que representam os sinais mais aparentes de uma pele senil. Na busca pela juventude, diversas técnicas de rejuvenescimento facial vêm sendo utilizado nos últimos anos, entre o quais acetilhexapeptídeo-3, um ativo de uso tópico que foi sintetizado com objetivo de mimetizar os efeitos da neurotoxina botulínica. Nesta perspectiva, o objetivo do presente trabalho foi analisar o processo de envelhecimento cutâneo e a ação do ativo acetilhexapeptideo-3 no processo de rejuvenescimento facial, por meio de uma revisão bibliográfica. O presente estudo caracterizou-se com uma revisão bibliográfica exploratória-descritiva com abordagem qualitativa, neste contexto buscou-se informações a respeito do processo de envelhecimento cutâneo e a ação do ativo acetilhexapeptídeo-3 no rejuvenescimento facial. Os resultados mostraram que o acetilhexapeptídeo-3, embora muito menos potente que a neurotoxina botulínica, promove melhoras significativas na aparência da pele envelhecida, justificando desta maneira seu uso em formulações cosméticas antienvelhecimento.
... In detail, the most common peptides that affect the biological function of acetylcholine include acetyl hexapeptide-3, pentapeptide-18, pentapeptide-3, acetyl octapeptide-3, and tripeptide-3. [303,336,337,344,348,349,[352][353][354]. These peptides can be considered to be valid alternatives to botulinum neurotoxin (Botox)-a protein produced by the bacterium Clostridium botulinum (which will be discussed later). ...
... When this analog peptide replaces SNAP-25, the SNARE complex is destabilized, and the release of acetylcholine is inhibited, resulting in muscle contraction being significantly reduced [334,337,353,354]. It was scientifically demonstrated that Argireline ® is a safe, effective anti-wrinkle ingredient [337,352,427], particularly suitable for eye care product formulation [345,354]. The results derived from clinical tests showed a wrinkle depth reduction of up to 16.9% within 15 days, and up to 27% within 30 days [395,396]. ...
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The “modern” cosmetology industry is focusing on research devoted to discovering novel neurocosmetic functional ingredients that could improve the interactions between the skin and the nervous system. Many cosmetic companies have started to formulate neurocosmetic products that exhibit their activity on the cutaneous nervous system by affecting the skin’s neuromediators through different mechanisms of action. This review aims to clarify the definition of neurocosmetics, and to describe the features of some functional ingredients and products available on the market, with a look at the regulatory aspect. The attention is devoted to neurocosmetic ingredients for combating skin stress, explaining the stress pathways, which are also correlated with skin aging. “Neuro-relaxing” anti-aging ingredients derived from plant extracts and neurocosmetic strategies to combat inflammatory responses related to skin stress are presented. Afterwards, the molecular basis of sensitive skin and the suitable neurocosmetic ingredients to improve this problem are discussed. With the aim of presenting the major application of Botox-like ingredients as the first neurocosmetics on the market, skin aging is also introduced, and its theory is presented. To confirm the efficacy of the cosmetic products on the market, the concept of cosmetic claims is discussed.
... Acetyl hexapeptide-8 is marketed as Argireline ® [11], and it has been efficiently used in cosmetics for smoothening the under-eye wrinkles and the forehead furrows [12][13][14]. After topical application at specific areas of the face, it inhibits the reactions that cause muscles to move or contract for example when forming facial expressions such as smiling or frowning [15,16]. A clinical trial of daily topical application of acetyl hexapeptide-8 in 24 patients with blepharospasm concluded that topical application of this peptide is safe and promising for prolonging the action of injectable botulinum neurotoxin therapy [17]. ...
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Bioactive peptides are gaining more and more popularity in the research and development of cosmetic products with anti-aging effect. Acetyl hexapeptide-8 is a hydrophilic peptide incorporated in cosmetics to reduce the under-eye wrinkles and the forehead furrows. Hydrophilic interaction liquid chromatography (HILIC) is the separation technique of choice for analyzing peptides. In this work, a rapid HILIC method coupled to photodiode array detection operated at 214 nm was developed, validated and used to determine acetyl-hexapeptide-8 in cosmetics. Chromatography was performed on a Xbridge® HILIC BEH analytical column using as mobile phase a 40 mM ammonium formate water solution (pH 6.5)-acetonitrile mixture 30:70, v/v at flow rate 0.25 mL min−1. The assay was linear over the concentration range 20 to 30 μg mL−1 for the cosmetic formulations and 0.004 to 0.007% (w/w) for the cosmetic cream. The limits of quantitation for acetyl hexapeptide-8 were 1.5 μg mL−1 and 0.002% (w/w) for the assay of cosmetic formulations and cosmetic creams, respectively. The method was applied to the analysis of cosmetic formulations and anti-wrinkle cosmetic creams.
... A study by Tadini et al., in which the effect of a regularly applied cosmetic product with retinoic acid on anisotropy was tested, showed that already at week 4, then also at week 8, positive changes in skin anisotropy were observed, similar to the ones in this study. Thus, the mechanical properties of the skin were improved, and thus the signs of skin aging were reduced [42]. Table 4 shows the amount of wrinkles at zero, four and eight weeks of application of the cosmetic gel formulation with chicken collagen hydrolysate. ...
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Chicken stomachs can be processed into collagen hydrolysate usable in cosmetic products. The aim of the study was to verify the effects of a carbopol gel formulation enriched with 1.0% (w/w) chicken hydrolysate on the properties of the skin in the periorbital area after regular application twice a day for eight weeks in volunteers ageed 50 ± 9 years. Skin hydration, transepidermal water loss (TEWL), skin elasticity and skin relief were evaluated. Overall, skin hydration increased by 11.82% and 9.45%, TEWL decreased by 25.70% and 17.80% (always reported for the right and left area). Generally, there was an increase in skin elasticity, a decrease in skin roughness, as the resonance times decreased by 85%. The average reduction of wrinkles was 35.40% on the right and 41.20% on the left. For all results, it can be seen that the longer the cosmetic gel formulation is applied, the better the results. Due to the positive effect on the quality and functionality of the skin, it is possible to apply the cosmetic gel formulation in the periorbital area. The advantage of the product with chicken collagen hydrolysate is also the biocompatibility with the skin and the biodegradability of the formulation.
... Microneedles enhance this process even 40-fold compared to passive diffusion. The clinical studies with Argireline peptide confirmed its efficiency and its potential as an active ingredient to be used in cosmeceuticals (Tadini et al., 2015;Raikou et al., 2017). Very recently, Lim et al. reported a relevant, wide study on acetyl hexapeptide-3, designing eye patches with microneedles to increase peptide delivery (Lim et al., 2020). ...
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Among the many aspects that contribute to the wellness of each individual, healthy and younger-looking skin play a relevant role, as clearly shown by the important growth of the skin-care products market observed in recent years. In this scenario, the field of cosmeceuticals appears particularly promising, being based on cosmetic products containing active ingredients. Among these, several peptides were proposed for cosmeceutical applications, thanks to their specific interaction with biological targets. In this mini-review, we report some of the most investigated and used peptides for cosmetic formulations, taking into account that cosmeceutical peptides are basically divided into three main categories, i.e., neurotransmitter inhibitors, carriers, and signal peptides. Special attention was payed to the scientific studies supporting the claimed biological activity of these peptides, as a fundamental aspect that should underpin the growth of this field in the framework of a sustainable wellness economy.
... The mechanical properties of human skin such as stiffness, damping coefficient, shear modulus, and Young's modulus have been received particular attention in recent years. These properties are important for many medical or engineering applications such as cosmetic products (Tadini et al., 2015), clinical use (Gabriel and Kowalske, 2015), industrial application (Grujicic et al., 2009), tissue engineering (Mohamed and Xing, 2012), and finite element modeling of the human body (Li et al., 2017). ...
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Characterization of viscoelastic properties of the human thigh skin can be utilized in many medical or engineering applications such as a surgical extension of the thigh skin, a tissue engineering, and a finite element modeling of thigh skin in a sitting posture. This study aims to determine the effective short- and long-term shear moduli of posterior thigh skin using ramp-relaxation test in a sitting posture. The effect of indentation location, the sitting posture, and the applied load (thigh weight) were investigated on the extracted effective shear moduli. We modeled the human skin by using the one- and two-term Prony series, and it was found that the generalized Maxwell model with two-term Prony series agreed well with experimental data. The effective shear moduli (short- and long-term) were extracted by fitting the total reaction force of the generalized Maxwell model to the experimental data using the Levenberg-Marquardt algorithm. The contour maps were used to show the spatial dependency of the effective shear moduli at the flat regions of posterior thigh skin. The contour maps of effective shear moduli show that maximum effective shear moduli locate near buttock’s center, while minimum effective shear moduli locate at the distal and medial posterior thigh. It is also found that the extracted effective short-term shear modulus varies between 3978.2 N/m² and 13699.2 N/m². On the other hand, the extracted effective long-term shear modulus differs between 2715.1 N/m² and 9194.3 N/m² for different sitting postures. Additionally, it is found that the observed increase in effective shear moduli could be attributed to the increase applied load, and leg angle.
... The bioactive acetyl hexapeptide-3 has been studied to some extent. Maia Campos and collaborators (2014) [39] evaluated the safety of this peptide by making use of the primary skin irritation test and the patch test. They describe having used a hypoallergenic adhesive tape (50 mm 2 area) applied a single time at occlusive conditions to the dorsal area of 27 volunteers (aged between 20 to 59 years) of phototypes II and IV. ...
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Peptides found in skin can act by different mechanisms of action, being able to function as epidermal or nervous growth factors or even as neurotransmitters. Due to the vast functionality of these compounds, there is growing research on bioactive peptides aimed at investigating their uses in products developed for stimulating collagen and elastin synthesis and improving skin healing. Thus, a literature search on applications of the most common bioactive peptides used in cosmeceuticals was carried out. There is a lack of proper reviews concerning this topic in scientific literature. Nine peptides with specific actions on body and facial dysfunctions were described. It could be noted while searching scientific literature that studies aimed at investigating peptides which prevent aging of the skin are overrepresented. This makes searching for peptides designed for treating other skin dysfunctions more difficult. The use of biomimetic peptides in cosmetic formulations aimed at attenuating or preventing different types of skin dysfunctions is a topic where information is still lackluster. Even though research on these compounds is relatively common, there is still a need for more studies concerning their practical uses so their mechanisms of action can be fully elucidated, as they tend to be quite complex.
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This paper reviews the advances made in recent years on modeling approaches and experimental techniques to characterize the mechanical properties of human skin. The skin is the largest organ of the human body that has a complex multi-layered structure with different mechanical behaviors. The mechanical properties of human skin play an important role in distinguishing between healthy and unhealthy skin. Furthermore, knowing these mechanical properties enables computer simulation, skin research, clinical studies, as well as diagnosis and treatment monitoring of skin diseases. This paper reviews the recent efforts on modeling skin using linear, nonlinear, viscoelastic, and anisotropic materials. The work also focuses on aging effects, microstructure analysis, and non-invasive methods for skin testing. A detailed explanation of the skin structure and numerical models, such as finite element models, are discussed in this work. This work also compares different experimental methods that measure the mechanical properties of human skin. The work reviews the experimental results in the literature and shows how the mechanical properties of human skin vary with the skin sites, the layers, and the structure of human skin. The paper also discusses how state-of-the-art technology can advance skin research.
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The development of synthetic peptides for skin care dates to the 1980s. The cosmetic industry periodically launches new peptides, as they are promising and appealing active ingredients in the growing and innovative cosmetics market. In this study, trends in the use of peptides in anti-aging products were analyzed by comparing the composition of the products marketed in 2011 with products launched or reformulated in 2018. The scientific and marketing evidence for their application as active ingredients in anti-aging cosmetics was also compiled from products’ labels, suppliers’ technical data forms and online scientific databases. The use of peptides in anti-aging cosmetics increased by 7.2%, while the variety and the number of peptide combinations in products have increased by 88.5%. The most used peptides in antiaging cosmetic formulations are, in descending order, Palmitoyl Tetrapeptide-7, Palmitoyl Oligopeptide and Acetyl Hexapeptide-8. In 2011, the majority of peptides were obtained from synthesis, while in 2018, biotechnology processing was the dominant source. This study provides an overview of the market trends regarding the use of peptides in anti-aging products, providing meaningful data for scientists involved in the development of new peptides to identify opportunities for innovation in this area.
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The beneficial effects promoted from the use of biomolecular substances into the formulations of personal care products are considered useful ingredients in cosmetic and therapeutic applications. Innovations in cosmetics are based on new bioactive formulations such as vitamins, oils, peptides, and protein hydrolysates. In skin care, the monomeric amino acids such as serine, threonine, alanine are common ingredients in cosmetics as they function as natural moisturizing factors which act as water-binding molecules. Amino acids and their salts e.g., arginine, glycine, etc. are also used as hair- and skin-conditioning agents in cosmetic formulations. The peptides are composed of short chain of amino acids and are used in cosmetics due to their numerous pathophysiological properties including anti-aging. There is growing interest in bioactive peptides in products for stimulating collagen and elastin synthesis in skin and improve surface healing. The main benefit of using proteins in cosmeceuticals is to improve the hydration of skin. Proteins increase the dehydration in the skin which helps to reduce wrinkles and improves the functions of the skin barrier. This review article describes the peptides, proteins that are most frequently used in cosmeceuticals and their potential benefits and practical use in cosmetic science and skincare.
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Background/Aims: The hydration state of stratum corneum can be measured with different instruments. In the present study, five instruments were compared under different experimental in vivo conditions: Corneometer CM 820 and CM 825 (both capacitance based), Skicon 200 (conductance), Nova DPM (impedance based capacitance) and DermaLab (capacitance). Methods: Seven anatomical sites were tested, a sorption-desorption test (SDT) and a moisture accumulation test (MAT) were performed. Different hydration states were created on the volar forearms by occluded application of an oil-in-water (o/w) emulsion, glycerol and urea containing oil-in-water (o/w) emulsion, an untreated control site and a site after lipid extraction with acetone. Measurements were performed 15 min after removal of occlusion. Results: The coefficient of variation for CM 820 ranged between 9.3% and 23.7%; for CM 825 between 14.9% and 36.8%; for Skicon 200 between 53.0% and 167.3%; for Nova DPM between 36.4% and 95.8%; for DermaLab between 23.6% and 45.6%. All devices showed a highly significant correlation (P < 0.0001) with a high Spearman coefficient r ranging between 0.7928 and 0.9358. Conclusions: CM 820 and CM 825 seem to differentiate more precisely than Nova DPM, Skicon 200 and DermaLab in dry conditions according to previous findings, i.e., that conductance measurements might be more sensitive for hydrated skin and capacitance measurements might be more sensitive for dry skin conditions. The CM 825, the Skicon 200 and the Nova DPM are suitable for dynamic measurements of hydration parameters of the stratum corneum.
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Anisotropy of the skin varies depending on different locations and pathological conditions. Currently, no reliable non-invasive measurement tool is available for tissue anisotropy. The Reviscometer is an anisotropy measurement tool that measures the resonance running time (RRT) of a shock wave. This study was initiated to establish the reliability of the Reviscometer on normal skin and scars, and to provide basic information on tissue alignment in normal skin and scars. Fifty volunteers and 50 patients underwent measurements on normal skin and scars, respectively. All measurements were performed by the same two observers. Measurements on normal skin were performed on the forearm, upper arm, and abdomen. The results showed that the intraclass correlation coefficient of the inter-observer reliability was > or =0.79 on normal skin and > or =0.86 on scars. In normal skin, the highest mean RRT was found on the abdomen (156.4+/-48.8), followed by the upper arm (123.2+/-33.6) and the forearm (112.5+/-24.3). A significantly lower mean RRT was found in scars (52.3+/-21.9) compared with normal skin (91.6+/-37.7). Reviscometer measurements were reliable for normal skin and scars. In addition, clear differences between scars and normal skin but also within different locations on normal skin were identified. The Reviscometer can be considered for the evaluation of the efficacy of different treatments.
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In nature, the majority of chemical reactions, biological responses, and regulatory processes are modulated in some part by specific amino acid sequences. The transfer of these interactive sequences and the biological activities they induce to short, stable, and readily synthesized peptides has created a diverse new field of modulating molecules applicable to dermatology and skin care industries. Areas such as inflammation, pigmentation, cell proliferation and migration, angiogenesis, innate immunity, and extracellular matrix synthesis have yielded peptide candidates for application to this area.
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Experiments on skin moisture, i.e. the hydration state of the outer epidermis, were undertaken using three different types of equipment, i.e. the Skicon-100 and Corneometer CM 420 hydrometers and the Servo Med EPI evaporimeter. The studies included 10 healthy volunteers. Water was applied to test sites on the forearm and the palm of the hand, and effects monitored by the three methods. Parallel increases in conductance, capacitance and transepidermal water loss were registered for a duration of about 5 min. The Skicon-100 was more sensitive for measurement of increased hydration, while the Corneometer CM 420 might be more sensitive for measurement of decreased hydration. Inter- and intra-individual variations were minor with all instruments. According to reproducibility studies, the Corneometer CM 420 was more accurate than the Skicon-100. Technical experiments indicated that the Corneometer CM 420 depicts changes of hydration down to a depth of 0.1 mm, while the Skicon-100 measures very superficially. In conclusion, both hydrometers were deemed relevant and valid for assessment of skin moisture. The methods are complementary, and their combined use is recommended.
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Using recently designed, commercially available, non-invasive instruments, we measured the thickness and elasticity of the skin of the face and ventral forearm in 170 women, and evaluated the effects of age and exposure to sunlight. Skin thickness decreased with age in ventral forearm skin, which has limited exposure to sunlight, but increased significantly in the skin of the forehead, corners of the eyes, and cheeks, which are markedly exposed to sunlight. Skin elasticity (Ur/Uf) decreased with age on both the face and forearm. The ratio of viscosity element to elasticity element (Uv/Ue) increased with age at all sites. However, delayed distension (Uv), immediate retraction (Ur), final distension (Uf), and immediate distention (Ue), as individual elements, decreased on the face and increased on the forearm with age. This tendency was more marked after correction for skin thickness. These results suggested the specificity of skin thickness and elasticity in the facial skin. Analysis using a four-element model showed no changes in the elasticity coefficient of Maxwell element on the forearm, but an increase on the face. This indicates quantitative or qualitative changes in elastic fibres in facial skin. Thus, sunlight appears to have a considerable effect on the thickness and physical properties of facial skin.
Article
Skin viscoelasticity was evaluated by a fast, noninvasive assay based on the measurement of the speed of elastic shear wave propagation in the skin by a new portable and user-friendly viscoelasticity skin analyzer. The range of speed of elastic shear wave propagation measured by viscoelasticity skin analyzer allows the evaluation of the stiffness of a wide spectrum of artificial materials as well as the viscoelasticity of skin of laboratory animals and human subjects. The directional nature of the measurement enables to monitor the anisotropy of the materials tested. The speed of elastic shear wave propagation was shown to have a positive correlation with the stiffness of the material tested. In symmetric contralateral areas of intact skin in rabbit ears, similar viscoelasticity and anisotropy were observed. Twenty-four hours after the induction of local edema by croton oil, skin stiffness and anisotropy were significantly increased. In healthy human subjects of both sexes significant variations in skin stiffness and anisotropy were observed in three different skin areas along the forearms, but the speed of elastic shear wave propagation was similar in the symmetric contralateral areas. Age (17-65 y) seemed to have a limited effect on the viscoelasticity of the forearm skin. Hydrating creams decreased the stiffness of the forearm skin for only approximately 3 h. The stiffness and anisotropy of the skin of the breasts in female volunteers (20-86 y) increased with age, but the speed of elastic shear wave propagation was similar in symmetric contralateral areas in the same individuals. Based on these results, we propose the application of the viscoelasticity skin analyzer in experimental and clinical practice for quantitative evaluation of skin condition.
Article
The in vivo visco-elastic characteristics of skin depend on a series of physiopathological parameters. Among them, the age-related intrinsic tensile properties and the preconditioning of the tissues set under tension by the hypodermal volume might be of importance. To revisit the influence of age and body mass on the firmness and mechanical anisotropy of the skin as determined by the velocity of the shear wave propagation. Resonance running time measurements (RRTM) were performed on the mid volar forearm in 110 adults of both sexes. In each subject 16 RRTM were collected at four different precise angles with regard to the limb axis. We recorded the lowest, the highest and the mean multidirectional RRTM as well as the coefficient of variation (CV) of the latter value. In addition, the body mass index (BMI) was calculated. Age and BMI did not influence the minimum RRTM. In contrast, the maximum RRTM as well as the mean and CV of the multidirectional RRTM, significantly rose in a progressively increasing proportion of the subjects older than 60 years. These changes were only encountered in subjects with a normal BMI ranging from 18 to 25. Sex-related differences were not disclosed. The intrinsic skin tension lines identified by the minimum RRTM are not significantly altered with age and BMI variations. In contrast, skin laxity identified by larger maximum and mean multidirectional RRTM may increase after 60 years of age in subjects with a normal BMI. This is accompanied by increased skin mechanical anisotropy identified by CV values of the multidirectional RRTM over 40%.
Article
The body posture and gravitational forces govern in part the intrinsic skin tensile strength because they influence the orientation of the dermal fibre networks. Our objective was to assess changes in shear wave propagation in the skin according to the body posture and orientation of the gravitational forces. The study was performed in 30 middle-aged women with a normal body mass index. The Reviscometer was used to assess the mechanical wave propagation on the volar forearm in extension or flexion. Similar measurements were made on the supra-areolar region of the breast when the trunk was in the horizontal or vertical position. Four measurements were made in each of 4 directions at given angles with regard to the body axis. The device gave reproducible data. Shear wave propagation was influenced by the body posture. The intra-individual variability in shear wave velocity according to the directions of measurements increased when the tissues were in a relaxed position. Skin tensile anisotropy increased in a relaxed body posture. Shear wave propagation may be a convenient non-invasive tool to better identify the natural skin tension lines in the skin, thus refining the orientation of incision during cutaneous surgery.
Article
Background/aims: The Cutometer equipped with a 2-mm diameter suction probe is a device suitable for assessment of epidermal mechanics. The objectives of this study were to determine the sensitivity of Cutometer parameters to epidermal hydration, to evaluate the correlation between skin mechanical parameters and skin capacitance, and to study the role of pretension of the skin. Methods: In the first study, skin capacitance (Corneometer) and 10 mechanical parameters were determined before and 60 min after application of five different moisturizers on the volar forearm. In the second study, measurements of epidermal mechanics were made without and with 0.1 s presuction of the skin, before and 120 min after application of petrolatum and glycerin. Results: Hydration of the skin significantly increased the values of capacitance and all rheological parameters. Delayed distension (Uv) and viscoelastic-to-elastic ratio (Uv/Ue) were the most sensitive Cutometer parameters. Significant correlations between skin capacitance and mechanical parameters were not found. Pretension of the skin did not significantly influence the values of skin mechanical parameters. Conclusions: The non-invasive measurements of skin elasticity are appropriate for an objective and quantitative evaluation of the complex effect of different dermatological and cosmetic products on skin mechanics and hydration.
Article
Beyond subjective assessments, the effect of skin tensors is difficult to assess. The present 2-phase randomized double-blind split face study was designed to compare the effect of a gel containing 3% 2-dimethylaminoethanol (deanol, DMAE) with the same formulation without DMAE. In a first pilot study, sensorial assessments and measures of the skin distension under suction were performed in eight volunteers. In a second study conducted in 30 volunteers, shear wave propagation was measured. Large interindividual variations precluded any significant finding in the first study. The DMAE formulation showed, however, a significant effect characterized by increased shear wave velocity in the direction where the mechanical anisotropy of skin showed looseness. The DMAE formulation under investigation increased skin firmness.