Moisturizing and Cosmetic
Properties Of Emu Oil:
A Double Blind Study
Presented at the AEA national convention
in
Nashville, Tennessee. August 1994
Alexander Zemtsov, M.D., M.S. Indiana University
School of Medicine
Monica Gaddis, Ph.D. Ball Memorial
Hospital
Victor Montalvo-Lugo, M.S. Ball
Memorial Hospital
Summary
Cosmetic and
moisturizing properties of emu oil were assessed in a double blind clinical
study. Emu oil in comparison to mineral
oil was found overall to be more cosmetically acceptable (p<0.05). Furthermore, it appears that emu oil in
comparison to mineral oil has better moisturizing properties, superior
texture, and lower incidence of comedogenicity, but probably because of the
small sample size these differences, were not found to be statistically
significant (p<0.05). Neither of
the oils were found to be irritating to the skin. Finally, emu oil fatty acid composition
was studied by gas chromatography and was found to have high concentration
of nonpolar monounsaturated fatty acids which may explain emu oil’s ability
to penetrate easily through the stratum corneum barrier.
Introduction
The emu, a large
flightless bird, Dromaius novaehollandiae, is probably best known for being
on Australia’s
coat of arms opposite the kangaroo.
In the past few years commercial emu breeding has become a
multi-million dollar industry in the United States, Australia,
and other countries. Emu oil derived
from emu fat was being used by the Aborigines for healing and pain control
long before British ships landed on the eastern shores of Australia.
A number of
Australian investigators (George Hobday, M.D., a dermatologist and Peter
Ghosh, Ph.D., FRSC at the University
of Sydney) claimed
that emu oil has anti-inflammatory and skin penetrating properties. Recently the Australian Department of
health classified emu oil as a pharmaceutical product1 and registered emu oil in the Therapeutic
Goods Registry2. Finally
an official Australian government publication stated “the oil (emu) will
find uses in the pharmaceutical and cosmetic industries”. We performed an extensive literature
search (Medline, Index Medicus) and could not find a single report in
scientific peer reviewed literature dealing with either emu oil and its
cosmetic pharmaceutical properties of its composition1. A pilot double blind study was conducted
to assess cosmetic properties of emu oil – namely its moisturizing and skin
penetrating properties, texture and odor, and irritancy and comedogenicity
potential. The emu oil was compared
in this study to mineral oil, a synthetic oil that is widely used in the United States
as an emulsifier and lubricant in topical cosmetical and pharmaceutical
preparations.
Methods
Human Subjects
11 subject were
recruited and completed the study (9 women and 2 men). Mean age was 35 years (age range 25-52),
10 subjects were white Caucasian and one subject was Hispanic. All had Fitzpatrick skin type 2 or 3
based in history of response to UV radiation. All had healthy skin and people with
eczema and acne were specifically excluded from this study. Since both emu and mineral oil can be
purchased in the United States over the counter, no human subject research
permit was required of issued by the Texas tech Human Subject Institutional
Review Board.
Oil:
Emu oil for
clinical study was imported from Australia (Emu Vertica, Thalgo
Holdings Pty. Ltd.). Both Australian
emu and mineral oil were placed in dark, numbered bottles by a pharmacist
(Caprock Drugs, Lubbock,
TX). Neither human subjects or principal
investigator knew which oil each subject was using at what particular
time. The code was not broken until
all volunteers completed the study and returned the questionnaire to the
principal investigators.
Oil Composition:
Fatty acid
analysis by gas chromatograph was performed by Dr.. Margaret
Craig-Schmidt’s laboratory of Auburn University and the results were
reported in the AEA News September, 1994.
Protocol:
Prior to entering
the study each subject was examined by a university based dermatologist to
make sure that none of the volunteers had eczema or acne. The volunteers were instructed to use the
first oil on their face and trunk twice a day for 2 weeks. The human subjects were told to discontinue
use of any other lubricants. After 2
weeks of oil use the human subjects were briefly examined by the principal
investigator for signs of skin irritation or acne and at that time were
given a second oil. The pharmacist
made sure that each subject received both emu oil and mineral oil. At the end on the study each subject
completed the questionnaire and ranked on a 0 to 5 scale (5 excellent; 0
poor) how much they liked each oil.
There were also asked to rank its penetration/permeability,
moisturizing properties, texture, and any side effects (comedogenicity,
odor, irritancy, etc.)
Statistical Analysis:
The data
generated was in a created ranking scale format [0 (poor); 5 (excellent)] and
was analyzed by a biostatistician utilizing the Wilcoxan Signed ranking
test.
Results
As shown in Table
I, the emu oil overall ranking and permeability was found to be clearly
superior to mineral oil. These
differences in skin penetration/permeability and overall ranking were
statistically significant (p<0.05).
It also appears that emu oil texture and moisturizing properties as
judged by the participants in the study were also superior to mineral oil,
but the differences cannot be considered statistically significant
(p>0.05). The sample size was
small (n=11) and it is very possible that if more people participated in
the study the clear cut statistical differences in the oils texture and
moisturizing properties would have been found.
When the participants
in this study were asked which of the two oils they liked better, all 11
subjects (100%) stated that they liked emu oil better (Table II). Neither emu oil or mineral oil was found
to be irritating to the skin (0%, Table II). Finally, when the oils were applied to
the face, 6 people (55%) and 2 people (18%) reported the mineral and emu
oil respectively caused “pimples”, (Table II).
Discussion
This pilot, a
double blind crossover study, clearly indicated that emu oil may become
widely used in cosmetic and pharmaceutical industries. We found emu oil to be totally
non-irritating, having excellent moisturizing properties, cosmetically
pleasing texture, and low incidence of comedoginicity. The most intriguing properties of emu oil
as far as cosmetic and pharmaceutical industries are concerned is its
apparent ability to penetrate the stratum corneum barrier. The study of penetration of various
substances through the skin is an area of an active research and is obviously
important from the therapeutical and toxicological viewpoints. Iontophorisis3 , and liposome
preparations4,5 are actively studied as a means to increase
cutaneous bioavailability. Since
most topical vehicles have an absorption rate of only a few percent6
the drugs and other active ingredients combine with more efficient drug
carrier systems are of major interest to cosmetic and pharmaceutical
industries. As a matter of fact,
liposome preparations containing the anti-fungal agent econzole (econazole
1%; pevarly; cilag; Schafflausen, Switzerland) and cosmetics with liposene
base are now available in the United States and Western Europe4,5.
Unfortunately,
because of high cost and other technical problems neither liposome or
iontophorisis are now widely used in either cosmetic or dermatological
topical preparations3,4 .
If indeed, as we report in this paper, emu oil has superb skin
penetrating properties, as judged subjectively by participants in this
study, and because of relatively low cost, emu oil should be of major
interest to dermatologists and cosmetic scientists as a transcutaneous
carier system. It would not be
unreasonable to try to combine emu oil with topical antifungals, steroids,
retinoids, antihistamines, anesthetics, antiangrogen, and immunosuppressive
drugs to see if emu oil improves cutaneous bioavailability.
Even prior to
completion of this study a number of investigators became aware of apparent
penetrating properties emu oil. As
was noted in the methods section of this article, the composition of emu
oil was studied by Dr. Craig-Schmidt utilizing gas chromatography. The findings were that emu oil is
predominately composed of short chain monounsaturated fatty acids slowing
it to easily penetrate the stratum corneum.
Another investigator utilizing thin layer chromatography (TLC) found
that emu oil is essentially free of phospholipids thus enabling it to
penetrate readily through skin (Allen Strickland, personal communication).
We believe that
this apparently first scientifically conducted study addressing cosmetic and
pharmaceutical properties of emu oil is very promising. We are in the process of organizing in
the United States a much larger multicenter similar double blind study to
confirm our findings. Furthermore,
Dr. Craig-Schmidt’s research group is in the process of conducting in-vitro
transmembraneous skin penetration studies with emu oil to determine its
transcutaneous permeability. We hope
that this and the future study with emu oil to determine its transcutaneous
permeability. We hope that this and
the future study mentioned above will fully assess the cosmetic,
moisturizing, and pharmaceutical properties of emu oil.
Table I- The oil’s
ranking by the participants of the study
|
|
Emu
Oil
|
Mineral
Oil
|
P
|
Statistically
Significant
Difference
|
|
|
Median
|
Range
|
Median
|
Range
|
|
|
|
Overall Ranking of the Oil
|
5,000
|
(3-5)
|
3,000
|
(2,4)
|
0.020
|
Yes
|
Oil
Texture
|
4,000
|
(2-5)
|
3,000
|
(2-5)
|
0.540
|
No
|
|
Skin Permeability/ Penetration
|
5,000
|
(1-5)
|
3,000
|
(1-5)
|
0.016
|
Yes
|
|
Moisturizing Properties
|
5,000
|
(1-5)
|
4,000
|
(1-5)
|
0.062
|
No
|
Table II-The ranking and side effects by the
participants of the study
|
|
Emu Oil
|
Mineral Oil
|
|
Oil Preference
|
11 (100%)
|
0 (0%)
|
|
Comedogenicity
|
2 (18%)
|
6 (55%)
|
|
Irritancy
|
0 (0%)
|
0 (0%)
|
References
1Commonwealth of
Australia, Department of Health, Hosing and Community Services, Certificate
of a pharmaceutical Product No 92/0980
2AUST R 22759 in
the Australian Register of Therapeutical Goods.
3Singh J, Mabach
HI. Topical Iontophoretic Drug Delivery in vivo: Historical Development,
Devices, and Future Respectives.
Dermatology 1993: 187:235-238.
4Korting HC,
Blechek P, schaefer-Korting M, Wendel A.
topical liposome drugs to come:
What the patent literature tells us.
A review, J Am Academy of Dermatoloy 1991; 15:1068-1071.
5Schaefer-Korting
M, Korting HC, Braun-Falco O. Liposome Preparations; A step forward in
topical drug therapy for skin disease: A Review, J Am Academy of
Dermatology 1989; 21:1271-1275.
6Wester RC,
Maibach HI. Dermatopharmokinetics in
clinical Dermatology. Semin Dermatol
1983; 2:81-84
All correspondence should be
addressed to: Alexander Zemtsov, M.D., M.S., Research Dept., Ball Memorial Hospital,
2401 University Ave., Muncie, IN 47303-3499. Phone (317)747-8458 of (317
741-1975. Fax (317)747-8459. This work was supported by a grant from
the American Emu Association, Dallas, TX.
|
