The Effects of the Oral Supplementation with a Natural Keratin Hydrolysate (Kera-Diet®) on Hair and Nails: Randomized, Placebo and Benchmark-Controlled Clinical Trial on Healthy Females

Abstract

Background Telogen effluvium (TE) and its acute form (aTE) are two of the commonest occurrences in a trichology clinic, with patients claiming excessive hair shedding. ATE can occur in people of any age and ethnicity and is considered to be a quite common condition in either sex even if women are more likely to have a lowered quality of life and restricted social contacts as compared to men as a result of hair loss. Brittle nail syndrome (BNS) is a common condition affecting up to 20% of the population, especially women over 50 years of age. Nails affected by BNS appear ragged, thin, and dull. The clinical features of BNS include horizontal splits within the nail plate (onychoschizia) and increased longitudinal ridging or splitting (onychorrhexis). In BNS oral supplementation, trace elements and amino acids (especially L-Cystine) have been reported to be useful to ameliorate the nail plate condition. Objective We hypothesized that a nutritional approach, with nutrients of which the composition is close to the human keratin, could be effective to decrease hair loss during telogen effluvium and to improve brittle nails condition. At this purpose, a clinical study was designed to investigate the efficacy of a natural keratin hydrolysate obtained from a non-human source (feathers) on both aTE and BNS. Methods The in vivo effects of a natural keratin hydrolysate, Kera-Diet® (KD) upon human hair and nails condition was tested in a randomized, double-blind, parallel-group, benchmark (BE) and placebo (PL) controlled study involving 60 women during 90 days. In all subjects, Anagen/Telogen hair, hair volume and density, pull test, global photography, hair and nails brightness, and nail plate growth were measured at baseline and after 45 and 90 days of products use. A self-assessment test was carried out at the end of the study. Results With the KD treatment group, hair density, percentage of hair in anagen phase, hair and nails brightness, and nails growth were significantly increased compared to PL treatment group. Interestingly, with this same group, the diagnosis of aTE by pull testing was negative from 45 days. The efficacy of KD was equal to or greater than PL treatment group. Conclusion In this study, we demonstrated that daily oral administration of 1000 mg during 3 months of a natural extensively keratin hydrolysate, Kera-Diet®, associated to trace elements and specific vitamins was effective to improve both hair and nails condition. Furthermore, it demonstrates the role of nutrients in both aTE and BNS.

Full text

TRICHOLOGY AND COSMETOLOGY
Open Journal
ISSN 2771-7461
Vincenzo Nobile, PhD1; Francesco Tursi, PhD1; Enza Cestone, MD1; Renaud Sergheraert, Eng2; Joel Duperray, Eng2*
1Complife Italia Srl,Via Monsignor Angelini 21, 27028 San Martino Siccomario (PV), Italy
2BCF LIFE Sciences, Boisel, 56140 Pleucadeuc, France
*Corresponding author
Joel Duperray, Eng
BCF LIFE Sciences, Boisel, 56140 Pleucadeuc, France; Tel. +33 (0) 2 97 26 91 21; E-mail: jduperray@bcf-lifesciences.com
Article information
Received: November 23rd, 2020; Revised: January 8th, 2021; Accepted: January 12th, 2021; Published: January 29th, 2021
Cite this article
Nobile V, Tursi F, Cestone E, Sergheraert R, Duperray J. The effects of the oral supplementation with a natural keratin hydrolysate (Kera-Diet®) on hair and nails:
Randomized, placebo and benchmark-controlled clinical trial on healthy females. Trichol Cosmetol Open J. 2021; 4(1): 7-16. doi: 10.17140/TCOJ-4-115
The Eects of the Oral Supplementation with a Natural
Keratin Hydrolysate (Kera-Diet®) on Hair and Nails:
Randomized, Placebo and Benchmark-Controlled Clinical
Trial on Healthy Females
Original Research
Copyright 2021 by Duperray J. This is an open-access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0), which
allows to copy, redistribute, remix, transform, and reproduce in any medium or format, even commercially, provided the original work is properly cited.
7Original Research | Volume 4 | Issue 1 |
cc
ABSTRACT
Background
Telogen efuvium (TE) and its acute form (aTE) are two of the commonest occurrences in a trichology clinic, with patients claim-
ing excessive hair shedding. ATE can occur in people of any age and ethnicity and is considered to be a quite common condition
in either sex even if women are more likely to have a lowered quality of life and restricted social contacts as compared to men as
a result of hair loss. Brittle nail syndrome (BNS) is a common condition affecting up to 20% of the population, especially women
over 50 years of age. Nails affected by BNS appear ragged, thin, and dull. The clinical features of BNS include horizontal splits
within the nail plate (onychoschizia) and increased longitudinal ridging or splitting (onychorrh exis). In BNS oral supplementa-
tion, trace elements and amino acids (especially L-Cystine) have been reported to be useful to ameliorate the nail plate condition.
Objective
We hypothesized that a nutritional approach, with nutrients of which the composition is close to the human keratin, could be
effective to decrease hair loss during telogen efuvium and to improve brittle nails condition. At this purpose, a clinical study was
designed to investigate the efcacy of a natural keratin hydrolysate obtained from a non-human source (feathers) on both aTE
and BNS.
Methods
The in vivo effects of a natural keratin hydrolysate, Kera-Diet® (KD) upon human hair and nails condition was tested in a random-
ized, double-blind, parallel-group, benchmark (BE) and placebo (PL) controlled study involving 60 women during 90 days. In
all subjects, Anagen/Telogen hair, hair volume and density, pull test, global photography, hair and nails brightness, and nail plate
growth were measured at baseline and after 45 and 90 days of products use. A self-assessment test was carried out at the end of
the study.
Results
With the KD treatment group, hair density, percentage of hair in anagen phase, hair and nails brightness, and nails growth were
signicantly increased compared to PL treatment group. Interestingly, with this same group, the diagnosis of aTE by pull testing
was negative from 45 days. The efcacy of KD was equal to or greater than PL treatment group.
Conclusion
In this study, we demonstrated that daily oral administration of 1000 mg during 3 months of a natural extensively keratin hy-
drolysate, Kera-Diet®, associated to trace elements and specic vitamins was effective to improve both hair and nails condition.
Furthermore, it demonstrates the role of nutrients in both aTE and BNS.
Keywords
Keratin hydrolysate; Oral supplementation; Telogen efuvium; Hair growth; Brittle nail syndrome; Onychoschizia; Clinical study.

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Duperray J et al8 Original Research | Volume 4 | Issue 1 |
INTRODUCTION
In recent years, it has becoming increasingly accepted that food
supplements have benecial effects on human health. Their role
in correcting nutritional deciencies, maintaining an adequate in-
take of certain nutrients, and in supporting specic physiological
functions is extensively accepted among the scientic community.
The increasing interest in food supplement use and their popularity
also gained the attention of the council for responsible nutrition
(CRN) and pollsters. An online survey conducted online by Ipsos
Public Affairs for the CRN, found that 76% of adults in the United
States take food supplements.1 Interestingly, the same percentage
of respondents perceives the food supplement industry as trust-
worthy with an increasing trend by 3% from the previous year.
This evidence rapidly gained the attention of both the industry
and the consumers and the role of food supplements in support-
ing specic physiological functions was associated with the impact
of nutritional deciencies and their effect on skin, hair, and nails.
Despite the relationship between nutrition and skin, hair, and nails
has been difcult to substantiate in dermatology, there is reason to
believe that a healthy diet can signicantly contribute to their ap-
pearance; therefore, natural bioactive compounds administered by
the oral route can represent an effective way to improve both hair
and nails conditions.2,3 Some food supplements are well known to
be effective due to the historical use and word of mouth while oth-
ers were demonstrated to be effective in extensive studies on their
efcacy. However, when it comes to the claims accompanying skin,
hair, and nails food supplements, most of the time, they are not
supported by evidence-based-science.2,4
In a previous study, we demonstrated the effect of L-
Cystine amino acid in improving hair and nail conditions.5 Nowa-
days, due to the increasing evidence that protein-based dietary
supplements can be effective in reducing hair loss6 and improving
nails conditions,7 we extended our previous research to nutrients
obtained from poultry feathers which composition is close to the
human keratin and also highly bioavailable for the organism. As a
matter of fact, the use of animal co-products in food supplemen-
tation represents an effective way to make them value-added prod-
ucts and to decrease their impact on the environmental pollution.8
The reason behind our interest in hair and nails was re-
lated to their impact on the subject’s self-esteem and wellness. Hair
and nails are imbued with more social and psychological signi-
cance than with biological importance. Although most of the hair
and nails altered conditions are not life-threatening, they have a
signicant impact on the affected subject’s wellness and their social
interactions. Both for men and women, hair is a physical attribute
expressing their individuality and attractiveness.9 The expression
“bad hair day” or “tearing my hair” are emblematic and testimo-
ny to the psychological importance of hair. In 2001, Williamson
and collaborators reported a decrease of the quality of life and
restricted social contacts, correlated with symptoms of depression,
in subjects of both sexes affected by various forms of hair loss10
with a more severe psychological impact among women than in
men.11,12 Among all the hair loss disorders, we focused our atten-
tion on acute telogen efuvium (aTE). The term “telogen efu-
vium” (TE) was proposed to differentiate a dermatological condi-
tion characterized by diffuse, non-scarring shedding of hair from
excessive shedding of normal club hair.13 Telogen efuvium is one
of the most common causes of alopecia. Most of the cases of TE
are subclinical therefore its real incidence is not known14 even if it
is considered to be quite a common condition with a large percent-
age of adults experiencing an episode of TE at some point of their
life.15 Despite there the absence of clear data on the TE incidence
it is well known that it can occur both in men and women with-
out any racial predilection.14,15 Women take hair shedding problem
more seriously than men and are likely over-represented in seeking
medical treatment.16-19
Like hair also nails are a physical attribute with a signi-
cant impact on the individual psychology and attractiveness. The
expression “bite my nail” and nail-biting are emblematic behav-
iors in such situation in which a subject is nervous, frustrated or
stressed. The impact of nails disorders on the quality of life was
reported by Belyayeva and collaborators in a study including 1063
patients with nails disorders. The authors found, among others,
that the quality of life was statistically signicantly more affected
in patients with nails structure abnormalities. It is interesting to
note that the authors concluded that the impact on the quality of
life is more related to the appearance of the nails than the severity
of the disorder.20 Among all the nails disorders we focused our at-
tention on the “brittle nail syndrome (BNS)”. The clinical signs of
BNS include horizontal splits within the nail plate (onychoschizia)
and increased longitudinal ridging or splitting (onychorrhexis): the
impairment of intercellular adhesive factors of the nail plate is ex-
pressed as onychoschizia; while the involvement of the nail matrix
is expressed as onychorrhexis.21 The incidence of BNS was esti-
mated by 20% of the population, especially women over 50 years
of age, with ngernail fragility being more prevalent than toenail
fragility.22
MATERIALS AND METHODS
This was a single-site, randomized, double-blind, placebo- and
benchmark-controlled study. Before any study-related procedures
take place, the subjects were informed on study risks and benets.
Informed subjects were then asked to sign an informed consent
form. The study protocol and the informed consent form were
approved by the “Independent Ethical Committee for Non-Pharmaco-
logical Clinical trials” during its meeting on December 12th, 2016.
The study duration was 90 days. Subjects attended clinic visits at
baseline and after 45 and 90 days product intake. Each subject
took 1000 mg/day of a natural keratin hydrolysate (Kera-Diet® or
benchmark product) or a placebo for 90 days. Primary endpoints
were the measurement of anagen/telogen hair and the nail growth
speed. The study ow and the schedule of assessments chart is
reported in Figure 1.
The study took place at Complife Italia dermatological
facilities in San Martino Siccomario (PV), Italy. Complife Italia is
an independent testing laboratory for in vitro and in vivo safety and
efcacy assessment of cosmetics, food supplements, and medical
devices.

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Duperray J et al 9
Original Research | Volume 4 | Issue 1 |
Subjects
Participants (N=60, n=20 subjects per each treatment arm) were
enrolled at Complife Italia by a board-certied dermatologist. In-
clusion criteria were general good health, age between 30 and 60
years old, ongoing aTE and BNS (not pathological condition), no
alimentary/eating disorders (i.e. bulimia, psychogenic eating disor-
ders, etc.), and known history of metabolic syndrome. Non-inclu-
sion criteria were pharmacological treatments known to interfere
with the test product or masking the testing product effects (e.g.
anti-mitotic, cytotoxic drugs other than antineoplastic, retinoids,
androgens, anti-androgens, anti-epileptic agents, interferon-alpha),
simultaneous participation in a similar study, history for radiother-
apy or chemotherapy treatments, scalp surgery (e.g. hair transplan-
tation), pregnancy (included intention to become pregnant) and
lactation, use of food supplements having an inuence on hair
loss growth and on nail plate, systemic or local treatments for an-
drogenetic alopecia (Minoxidil, Aminexil, Finasteride, Dutasteride,
cosmetic solution or capsules with vitamin B, zinc, caffeine), exces-
sive or uctuating hair shedding for more than 6 months. Before
study initiation subjects were asked to cut their nails 7 days before
and after each checkpoint. Subjects were asked to refrain from hair
dyeing and to cut their hair during all the study period.
The number of subjects to be included in the study panel
was calculated using a statistical software (PASS 11, Version 11.08
for Microsoft Windows). A sample size of 20 subjects per group
was necessary given an anticipated dropout rate of 20%.
Intervention
All subjects were given a three-month supply of the test prod-
uct (Kera-Diet®, BCF Life Sciences, Boisel, 56140 Pleucadeuc,
France), benchmark product or placebo product. The way of use
was as follows: 2 capsules at breakfast and two capsules at dinner.
The ingredient list of each product is reported in Table 1. The total
active (Kera-diet® or benchmark keratin) intake per day was 1000
mg. Kera-diet® has an amino acid prole similar to human hair and
contains a high-level of free amino acids (>92 %) (Figure 2). The
active (KD), Benchmark (BE) and placebo (PL) products distribu-
tion was stratied using biased coin Efron’s algorithm with a 1:1:1
allocation ratio (PASS 11, version 11.0.8; PASS, LLC. Kaysville,
UT, USA). The allocation sequence was concealed from the in-
site study director in sequentially numbered, opaque, and sealed
envelopes, reporting the unblinded treatment allocation (based on
subject entry number in the study). The A4 sheet reporting the
unblinded treatment was folded to make the envelope imperme-
able to intense light. After acceptance of the subject in the study,
the appropriate numbered envelope was opened. The test prod-
ucts were dispensed by a technician according to the masked ran-
domization card contained in each envelope. The investigator and
its collaborators who obtained outcome measurements were not
informed on the product group assignment. Neither the investiga-
tor (and her collaborators) nor the study subjects knew who was
getting the active or the benchmark products and who was getting
the placebo products. The active, benchmark and placebo products
were in capsule form and identical in appearance. They were pre-
packed in blisters and consecutively numbered for each subject ac-
Figure 1. Study Flow and Schedule of Assessment Chart
NC: nail cut, PHc: Photricogram hair cutting, PT: pull testing, BR: Brightness measurement, GP: Global photography,
CL: Global photography scoring, NG: Nail growth rate, PHm: Photricogram hair measurement, SA: Self- assessment
questionnaire.

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Duperray J et al
cording to the randomization schedule. Each subject was assigned
an order number and received the capsules in the corresponding
prepacked blister.
Hair Loss Measurement/Assessment
Hair loss related parameters were measured/investigated by both
phototrichogram and pull testing.
Phototrichogram: A target area of the scalp (mid vertex) was
clipped using a hair trimmer (Moser edition, WAHL Italia, Bo-
logna, Italy). Short-clipped hair were removed using an adhesive
tape. Three days (72±2-hours) after hair clipping, hair was dyed
using a commercially available hair dye (Goldwell topchic, black
2N, Darmstadt, Germany with Rondo 6% CrèmeOxyd, Coiffeur,
Cologne, Germany). After 15-minutes the colored area was thor-
oughly cleaned with an alcoholic solution (Kodan® Spray, Schülke
& Mayr, Vienna, Austria) and digital images were taken using a
DermoGenius camera (DermoScan GmbH, D-93055 Regensburg,
Germany). Pictures were then analyzed by TrichoScan® analysis
(software version 2.3). At follow-up visit, the target area was iden-
tied using a homemade repositioning device instead of a tattoo
landmarking.
Pull testing: The hair pull test was carried out by the dermatologist.
The procedure consists in gently pulling of a little clump (20-60
hair) of hair. Pull testing was repeated in three different scalp areas
(frontal, temporal, and occipital region). If more than three hair
per each area (or more than ten hair over the three areas) were
removed, the pull test was considered as positive and suggestive of
telogen efuvium.
Digital Pictures and Image Analysis
Digital photographic pictures of the hair (the vertex and frontal
level) and the nail plate were taken under standard lighting condi-
tions using a professional digital reex camera NIKON D300/
D600 digital (Nital S.p.A., 10024 Moncalieri, To, Italy) camera
equipped with a macro-objective (AF-S Micro NIKKOR 60 mm
f/2.8G ED), an independent ash system (Kit R1C1) and with
cross- and parallel- polarized lters.
Nail plate growth was measured, using a morphometric
image analysis technique, as the difference between the total nail
length after cutting and the total nail length after 14 days from cut-
ting.
Clinical Scoring
The overall hair volume was scored by the dermatologist on the
pictures taken before and after treatment using a seven-point rat-
ing scale as follows: +3 greatly increased hair volume; +2 moder-
ately increased hair volume; +1 slightly increased hair volume; 0 no
change in hair volume; -1 slightly decreased hair volume; -2 mod-
erately decreased hair volume; -3 greatly decreased hair volume.23,24
Hair and Nails Brightness
Hair and nails brightness was measured using a spectrophotom-
eter/colorimeter CM-700D (Konica- Minolta, 20092 Cinisello Bal-
samo, MI, Italy). The measured parameter was the 8° gloss (specu-
larly reected light).
Self-Assessment Questionnaire
Subjects were asked to reply to the questions of a self-assessment
questionnaire.
Statistical Analysis
Statistical analysis was performed using NCSS 10 (version 10.0.12
for Windows; NCCS, LLC. Kaysville, UT, USA) running on Win-
dows Server 2008 R2 Standard SP1 64-bit edition (Microsoft, USA).
Data normality was checked using Shapiro-Wilk W normality test
and data shape. Intragroup (vs. baseline) statistical analysis was car-
ried out using repeated measures analysis of variance (RM- ANO-
VA) followed by Tukey-Kramer post-test. Intergroup (between
treatments) statistical analysis was carried out using RM-ANOVA
followed by tests for two-factor interactions. A p-value<0.05 was
considered statistically signicant. Statistical analysis output was
reported as follows: *p<0.05, **p<0.01, and ***p<0.001.
10 Original Research | Volume 4 | Issue 1 |
Figure 2. Kera-Diet® Aminoacidic Composition
Kera-Diet® is a hydrolysate of natural keratin, obtained from a non-human source (feathers),
mainly compounded of free amino acids (> 92%) with a similar prole to those of the hair.
Table 1. Capsule Composition. Quantities are Reported in mg
KD 250
mg
BE 250
mg PL
Ingredients
Maltodextrin 250 250 524.3
Kera-Diet®250 --- ---
Other keratin (benchmark ingredient) --- 250 ---
Magnesium stearate 14 14 14
Zinc sulphate heptahydrate (22% Zn) 11.36 11.36 ---
Silice 5 5 5
Vitamin B3 (nicotinamide) 4.5 4.5 ---
Vitamin B5 (D-Calcium pantothenate) 3.72 3.72 ---
Dry extract of aerial part of Equisetum
Arvense 2.5 2.5 ---
Copper sulphate pentahydrate 1.48 1.48 ---
Vitamin B6 (pyridoxine hydrochloride) 0.6326 0.6326 ---
Vitamin B8 (biotin) 0.15 0.15 ---

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Duperray J et al
RESULTS
The study was conducted between February and July 2017. A to-
tal of 60 female subjects were successfully randomized (Figure 3).
The population was Caucasian. Demographic and baseline char-
acteristics (Table 2) were similar across treatment arms, indicating
unbiased randomization and the absence of covariates. Subjects at-
tended clinic visits at the time of randomization (baseline) and after
45 and 90 days of product use. Data analysis was intention-to-treat
and involved all subjects who were randomly assigned. Subjects’
compliance to treatment was assessed by product accountability,
as follows: at each visit, the expected amount of consumed cap-
sule was compared with the amount dispensed minus the amount
the subject returned. No major deviations were observed in the
treatment regimen. All subjects were included in the safety analysis
data set. All the tested products were well tolerated. No adverse
reactions occurred during the study period. A statistically signi-
cant increase in hair density was observed both in the KD and BE
treatment groups (Table 3a). The hair density (number/cm2) was
signicantly increased in the KD treatment group by 2.1±0.7 and
by 13.3±1.7, after 45 and 90 days, respectively (p<0.001). A similar
efcacy prole was seen for the BE treatment group where hair
density was increased by 2.2±0.8 and by 9.6±1.3, after 45 and 90
days, respectively (p<0.001). The variation of hair density was not
statistically signicant in the placebo group (p>0.05). Both KD and
BE hair density variation was statistically signicant when com-
pared to the placebo group (p<0.05).
A statistically signicant increase of anagen hair was ob-
served both in the KD and BE treatment groups (Table 3b). The
percentage anagen hair was increased in the KD treatment group
by 3.6±0.6% and by 9.1±1.0%, after 45 and 90 days, respectively
(p<0.001). A similar efcacy prole was seen for the BE treat-
ment group where the percentage of anagen hair was increased
by 3.9±0.4% and by 8.6±0.9% after 45 and 90 days, respectively
(p<0.001). The variation of percentage of anagen hair was not sta-
tistically signicant in the placebo group (p>0.05). Both KD and
BE variation in the percentage of anagen hair was statistically sig-
Original Research | Volume 4 | Issue 1 | 11
Figure 3. CONSORT 2010 Flow Diagram
1. Enrolment, 2. Allocation, 3. Follow-up, 4. Analysis
Table 2. Demographic and Baseline Characteristics. Data are means±SE. KD
Kera-Diet®, BE Benchmark, PL Placebo
KD BE PL
Sex
Female 100% 100% 100%
Phototricogram
% telogen 21.3±0.6 20.7±0.7 21.0±0.8
% anagen 78.7±0.6 79.3±0.7 79.0±0.8
Hair density (hair no/cm2) 192.7±6.7 195.7±7.1 193.2±7.4
Pull test 12.3±0.3 12.6±0.4 12.3±0.3
Hair radiance 3.36±0.41 3.31±0.38 3.33±0.35
Nail growth rate (mm/14 days) 1.24±0.07 1.28±0.06 1.26±0.06
Nail brightness 7.32±0.72 7.41±0.50 7.28±0.51

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Duperray J et al
nicant when compared to the placebo group (p<0.05). The same
results were obtained for the percentage of telogen hair variation
(Table 3c).
A statistically signicant decrease of the number of
pulled hair was observed both in the KD and BE treatment groups
(Table 3d). The number of pulled hair was decreased in the KD
treatment group by 26.5±3.7% and by 32.7±3.6%, after 45 and
90 days, respectively (p<0.001). A similar efcacy prole was seen
for the BE treatment group where the number of pulled hair was
decreased by 22.9±2.2% and by 33.5±2.7% after 45 and 90 days,
respectively (p<0.001). A statistically signicant decrease of the
number of pulled hair (-10.6±2.6%) was seen in the placebo group
after 90 days of product use. Both KD and BE variation in the
number of pulled hair was statistically signicant when compared
to the placebo group (p<0.05). Interestingly, according to the pull
testing scoring system (number of pulled hair≤10 hair), the diag-
nosis of excessive hair shedding due to aTE was negative both for
KD and BE treatment groups.
Figure 4 shows the macroscopic effect of the product
in decreasing hair loss. Hair volume and nail conditions were im-
proved both in the KD and BE treatment groups. The subjects
showing an improvement of hair volume in the KD treatment
group were 40% and 65%, after 45 and 90 days respectively. A
simlar efcacy prole was seen for the BE treatment group where
Original Research | Volume 4 | Issue 1 |
12
Table 3. Phototricogram and Pull Testing Results
Mean±SE Min÷Max
n KD BE PL KD BE PL
a) Hair density (no./cm2)
Day 0 20 192.7±6.7a195.7±7.1a193.2±7.4a155.0÷250.6 152.7÷252.3 138.3÷246.2
Day 45 20 194.7±6.7b197.9±7.1b194.0±7.1a160.2÷251.2 160.1÷258.5 142.2÷248.4
Day 90 20 205.9±6.4c205.4±6.7c195.0±7.2a172.3÷266.3 165.2÷268.3 145.7÷256.3
D45-D0 20 2.1±0.7†2.2±0.8†0.8±0.8 -3.2÷7.2 -6.2÷12.9 -5.5÷5.9
D90-D0 20 13.3±1.7†9.6±1.3†1.8±0.9 -6.8÷21.2 -3.4÷40.2 -2.8÷10.1
b) Anagen (%)
Day 0 20 78.7±0.6a79.3±0.7a79.0±0.8a72.8÷82.5 71.1÷84.5 71.6÷83.7
Day 45 20 82.3±0.7b83.2±0.7b78.6±0.7a74.9÷89.8 77.9÷88.8 71.1÷84.5
Day 90 20 87.7±0.6c88.0±0.6c82.2±0.7b84.0÷91.9 83.6÷91.9 74.5÷87.6
D45-D0 20 3.6±0.6†3.9±0.4†-0.4±0.5 -0.3÷11.1 -0.2÷11.2 -5.5÷3.2
D90-D0 20 9.1±1.0†8.6±0.9†3.2±0.9 -11.1÷0.3 6.0÷18.2 -1.9÷12.3
c) Telogen Hair (%)
Day 0 20 21.3±0.6c20.7±0.7c21.0±0.8c17.5÷27.2 15.5÷28.9 16.3÷28.4
Day 45 20 17.8±0.7b16.8±0.7b21.4±0.7c10.2÷25.1 11.2÷22.1 15.5÷28.9
Day 90 20 12.3±0.6c12.0±0.6c17.9±0.7b8.1÷16.0 8.1÷16.4 12.4÷25.5
D45-D0 20 -3.6±0.6 -3.9±0.4 0.4±0.5 -11.1÷0.3 -11.2÷0.2 -18.2÷-6.0
D90-D0 20 -9.1±1.0†-8.6±0.9†-3.2±0.9 -18.0÷-1.5 -5.5÷3.2 -12.3÷1.9
Pulled Hair (Hair no.)
Day 0 20 12.3±0.3c12.6±0.4c12.3±0.3c11÷16 11÷17 11÷16
Day 45 20 8.9±0.4b9.7±0.5b12.4±0.5c4÷11 7÷16 10÷20
Day 90 20 8.1±0.4a8.3±0.4a11.0±0.5b3÷11 5÷12 8÷16
D45-D0 20 -3.4±0.6†-2.9±0.3†0.2±0.4 -11÷0 -5÷-1 4÷-2
D90-D0 20 -4.2±0.6†-4.3±0.4†-1.3±0.3 -12÷-2 -9÷-2 1÷-3
a) Hair density. b) Anagen hair. c) Telogen hair. d) Pull test results. Signicantly Different from D0:
a<b<c, p<0.05. RM-ANOVA followed by Tukey- Kramer Post-test. †Signicantly Different (p<0.05)
from Placebo. RM-ANOVA followed by Tests for Two-factor Interactions.
Figure 4. Global Photography Assessment
a) KD group b) BE group c) PL group

Trichol Cosmetol Open J. 2021; 4(1): 7-16. doi: 10.17140/TCOJ-4-115
Duperray J et al
the subjects improved were 30% and 55%, after 45 and 90 days.
The improvement was statistically signicant for both the KD and
BE treatment groups when compared to the placebo group (5%
and 10% of the subjects, after 45 and 90 days). The subjects show-
ing an improvement of nail conditions in the KD treatment group
were 30% and 60%, after 45 and 90 days; while the percentage of
subjects improved in the BE treatment group was 30% and 55%,
after 45 and 90 days. The improvement was statistically signicant
for both the KD and BE treatment groups when compared to
the placebo group (15% and 20% of the subjects, after 45 and 90
days).
Both the hair and nail brightness were statistically signi-
cant improved (Table 4) in the KD and BE treatment groups. Hair
brightness in the KD treatment group was improved by 23.8%
and 57.0%, after 45 and 90 days. A similar efcacy prole was seen
for the BE treatment group where hair brightness was improved
by 13.7% and 41.9%, after 45 and 90 days. The improvement
of hair brightness, both in the KD and the BE treatment group
was statistically signicant when compared to the placebo group
(p<0.05). Nail brightness in the KD treatment group was improved
by 33.1% and 35.7%, after 45 and 90 days; while the improvement
in the BE treatment group was 16.1% and 38.7%, after 45 and 90
Table 4. Hair and Nail Brightness
Mean±SE Min÷Max
n KD BE PL KD BE PL
Hair Brightness (au)
Day 0 20 3.36±0.41a3.31±0.38a3.33±0.35a0.64÷6.57 1.45÷8.17 1.04÷6.71
Day 45 20 3.98±0.45b3.74±0.42a3.28±0.36a1.16÷7.44 1.36÷8.98 1.08÷6.33
Day 90 20 4.99±0.53c4.68±0.55b3.53±0.39a1.20÷8.94 1.91÷10.7 1.17÷7.63
D45-D0 20 +23.8%†+13.7%†-1.90% -12.2%÷81.3% -8.1%÷47.7% -24.6%÷18.3%
D90-D0 20 +57.0%†+41.9%†6.40% -6.5%÷106.3% -1.1%÷88.7% -22.0%÷36.5%
Nail Brightness
Day 0 20 7.32±0.72a7.41±0.50a7.28±0.51a2.17÷12.47 3.32÷10.84 4.82÷12.66
Day 45 20 9.57±0.93b8.63±0.70b7.76±0.59a3.10÷17.10 4.02÷16.61 5.00÷13.45
Day 90 20 9.57±0.86b10.07±0.65c8.45±0.69b3.44÷15.15 4.51÷16.05 5.11÷14.85
D45-D0 20 +33.1%†+16.1%†6.70% 1.0%÷83.9% 2.1%÷84.0% 16.1%÷33.9%
D90-D0 20 +35.7%†+38.7%†17.20% 9.8%÷70.5% 5.9%÷88.1% 24.1%÷66.1%
Signicantly different from D0: a<b<c, p<0.05. RM-ANOVA followed by Tukey-Kramer post-test. † Signicantly
different (p<0.05) from Placebo. RM-ANOVA followed by tests for two-factor interactions.
Original Research | Volume 4 | Issue 1 | 13
Figure 5. Nail Growth Rate
Signicantly different from D0: a<b<c, p<0.05. RM-ANOVA followed by Tukey-Kramer post-test. † Signicantly different (p<0.05) from
Placebo. ∫ Signicantly different(p< 0.05) from Benchmark. RM-ANOVA followed by tests for two-factor interactions. Data aremeans±SE.
Mean±SE Min÷Max
n KD BE PL KD BE PL
Growth rate (mm/14 days)
Day 0 20 1.24±0.07a1.28±0.06a1.26±0.06a0.68÷1.99 0.72÷1.82 0.61÷1.60
Day 45 20 1.31±0.07b1.32±0.06b1.28±0.05a0.75÷2.08 0.75÷1.90 0.78÷1.65
Day 90 20 1.38±0.08c1.35±0.06c1.28±0.06a0.78÷2.14 0.79÷1.92 0.69÷1.68
D45-D0 20 +0.07†+0.04†0.02 0.01÷0.17 0.01÷0.08 -0.04÷0.17
D90-D0 20 +0.14†∫ +0.07†0.01 0.04÷0.27 0.02÷0.14 -0.03÷0.08

Trichol Cosmetol Open J. 2021; 4(1): 7-16. doi: 10.17140/TCOJ-4-115
Duperray J et al
days. Both KD and BE nail brightness variation was statistically
signicant when compared to the placebo group (p<0.05).
A statistically signicant increase of nail growth rate was
observed both in the KD and BE treatment groups (Figure 5).
In the KD treatment group the nail growth rate was 0.07±0.01
mm/14 days and 0.14±0.01 mm/14 days, after 45 and 90 days, re-
spectively (p<0.001); while in the BE treatment group nail growth
rate was 0.04±0.00 mm/14 days and 0.07±0.01 mm/14 days, after
45 and 90 days, respectively (p<0.001). The nail growth rate was
not statistically signicant in the placebo group (p>0.05). Both KD
and BE nail growth rate was statistically signicant when compared
to the placebo group (p<0.05). Moreover, KD group nail growth
rate was statistically higher than those of BE group (p<0.05).
The complete results of the self-assessment question-
naire are reported in Figure 6. Both KD and BE were perceived
more effective than PL. Subjects’ answers after 90 days of product
use are very positive with 75% global satisfaction for both KD and
BE group for hair and nails. On the other hand, placebo effect
is only 35%. This underlines that all improvement of objectives
criteria is enough visible to be perceived by women of KD and BE
groups.
DISCUSSION AND CONCLUSION
Hair and nails are two specialized keratinous skin appendages
growing at xed rate and with complete replacement over time.
The growth of both hair and nails relies on the metabolic activity
of the hair follicle and the nail matrix, respectively. It is then easy
to understand why, virtually, every nutritional deciency can affect
the growth of the nail in some manner.
The connection between nutrition and skin (and its ap-
Original Research | Volume 4 | Issue 1 |
14
Figure 6. Self Assessment Questionnaire
a) Hair self-assessment questionnaire. b) Hair self-assessment questionnaire. c) Overall self-assessment.

Trichol Cosmetol Open J. 2021; 4(1): 7-16. doi: 10.17140/TCOJ-4-115
Duperray J et al
pendages) conditions is a common interesting research eld for
both scientists and humans from ancient times to nowadays. It is
nowadays clear that the nutrients of diet have a direct impact on
the structure and growth of both hair and nails. To conrm that,
in recent years the use of food supplements has increased both
in Europe and in the USA with many physicians recommending
them.25,26
In our study, we demonstrated the role of a food supple-
ment containing a natural extensively hydrolyzed keratin in improv-
ing both hair and nails conditions after a 3 month intake period.
An improvement of hair conditions was seen after 90
days of treatment. This was demonstrated by the decrease of hair
shedding and telogen hair. The active group showed a signicant
decrease of telogen hair after 45 and 90 days treatment. The per-
centage of hair in the telogen phase was decreased, resulting in a
decrease of the number of hair loss on pull testing. Interestingly
the diagnosis of aTE by pull testing was negative after 45 days
treatment. Also, the hair ber showed a positive improvement,
demonstrated by the increase of its ability to reect the light (radi-
ance). This phenomenon relies on a healthy hair cuticle structure.
Nails also improved their conditions after 45 and 90 days
of treatment. After 90 days product use the 60% of the subjects
showed an improvement of nails condition. This was also demon-
strated by the increase of the nail growth rate by 0.14 mm/14 days.
The active product was also scored positively by most of
the subjects participating in the study. The subjects at the end of
the study perceived their hair and nails conditions as improved.
The efcacy of Kera-Diet® was comparable to that of the bench-
mark product.
The putative mechanism of action of the Kera-Diet® in
improving hair and nails condition can be attributed to its associa-
tion with traced elements and specic vitamins and also to the bio-
availability of amino acids from Kera-Diet® which is compounded
of more than 92% of free amino acids, of which the prole is
close to the human keratin.
No adverse effects were neither reported by the subjects
participating in the study nor by the investigator.
Therefore, and more generally, this study demonstrates
that Kera-Diet® associated with traced elements and specic vita-
mins at the right dosage can enhance hair and nails condition, even
though human nutrition is more and more balanced. The study,
furthermore, demonstrates the role of nutrients in both aTE and
BNS.
ACKNOWLEDGMENT
The authors would like to thank all the Complife Italia staff who
contributed to and recruited subjects for this study for their pro-
fessionalism and support during the study development.
FUNDING
This study was funded by BCF Life Sciences. BCF Life Sciences
was involved in the design of the study protocol and provided
the test products samples. Employees of the sponsor were not
involved in data analysis. The manuscript was prepared by Dr.
Vincenzo Nobile. BCF Life Sciences employees were permitted to
review the manuscript and suggest changes, but the nal decision
on content was exclusively retained by the corresponding author.
Dr. Vincenzo Nobile is the guarantor for this article and takes re-
sponsibility for the integrity of the work as a whole.
CONFLICTS OF INTEREST
The author has not received any funding or benets from industry
or elsewhere to conduct this study. Joël Duperray and Renaud Ser-
gheraert work for BCF Life Sciences.
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