Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides,
Skin aging is a complex phenomenon that induces numerous changes to the skin components (
Palmitoyl peptides,
Although various formulations of anti-aging cosmetics containing functional components are used and developed extensively for relieving skin aging such as wrinkles, low elasticity, low dermal density and photo damage (
The aim of the present study was to evaluate the anti-aging effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides,
This study complied with the principles of the Declaration of Helsinki and Korean and was reviewed and approved by the Institutional Review Board of Korea Institute for Skin and Clinical Sciences (Seoul, Republic of Korea).
A total of 20 female volunteers (age, 30–65) were selected on the basis of predetermined inclusion and exclusion criteria. Inclusion criteria were as follows: Volunteers were female and >30 years old; subjects voluntarily signed the informed consent form; subjects were healthy without acute or chronic physical diseases, including any skin diseases; and subjects were available for follow-up during the testing period. A person with any of the following factors was excluded from the study: Pregnant, breast feeding or potentially pregnant; person who had been treated with any external application containing steroids for a skin disease treatment for >1 month; had participated in the a similar test within the last 6 months; person with sensitive or hypersensitive skin; person with skin abnormality on the test site, including moles, acne, erythema, and dilated capillaries; person who received any treatment on the test area within the last 6 months. Participants were withdrawn for the following reasons and these were reported: Adverse events, such as itching or erythema at the test area; hindrance of the evaluation due to a medical treatment, application of another product, excessive sun exposure, or excessive drinking or smoking during the test period; inability to participate in a follow-up appointment during the test period due to personal reasons; and person who did not comply with the study directions without specific reason.
Adverse events, including erythema, edema, scaling, itching, stinging, burning, tightness, prickling and other abnormalities, were visually examined and described on the case report form at every visit. The records included the degree of symptoms and whether these were mild, moderate or severe. Each subject's attendance was also recorded. Whether the participant was excluded from the study due to withdrawal was also noted. If a subject was unable to continue in the study, she signed an abandonment consent form.
The facial cream and eye cream were freshly prepared for this study. The facial cream contains 1% palmitoyl oligopeptide and palmitoyl tetrapeptide-7 (BulkActives, Keelung City, Taiwan), 1%
Following facial washing, subjects applied the eye cream around eyes and face cream on the facial area twice per day, morning and night. Except for the test materials supplied by the institution, subjects were prohibited from using other products that may affect the results during the trial period. These other products included eye cream, functional cosmetics against aging and treatments such as masks or massages.
All clinical analyses were conducted after cleansing face with same cleanser (Cleansing Foam; Anna Holtz Skin Care, Incheon, Republic of Korea) and resting in a controlled temperature and humidity room (temperature, 22±1°C; humidity, 45±5%) for 30 min. All measurements were conducted prior to any test material application and subsequently after 2 and 4 weeks of application.
For evaluation of wrinkle improvement, a PRIMOS Lite 3D Face and Skin Scanner Analyzing System (GFMesstechnik GmbH, Berlin, Germany) was utilized. The outer corner of the right eye was measured three consecutive times with the PRIMOS Lite after placing subjects' face onto a special PRIMOS face-held-equipment (GFMesstechnik GmbH) and focusing the outer corner of eye on a same pattern of the PRIMOS Lite to prevent the test area from moving. The images adjusted to the same position each time by applying 3D matching and were analyzed with the PRIMOS Lite software (version 5.6E; GFMesstechnik GmbH). The measurement variable Ra (average of all heights and depths to the reference plane) was used for wrinkle analysis as the most common surface roughness index worldwide, which represents the maximal mathematical average of the profile within the entire measurement range. The Ra value decreases with a lower depth of wrinkles, indicating that skin wrinkles were improved.
For evaluation of skin elasticity improvement, the DermaLab USB elasticity probe (Cortex Technology ApS, Hadsund, Denmark) was applied. After attaching the probe to the skin with tape, the left cheek under the eye was measured only once for prevention of skin fatigue caused by repeated measurement. The DermaLab USB elasticity probe quantifies skin changes and restoring forces in accordance with inhalation of skin and the duration of the inhalation, and the results were analyzed using DermaLab USB analysis software, version 1.09 (Cortex Technology ApS). Young's modulus (E) was used for elasticity analysis, which is the value representing the difference in forces to raise surface skin as much as 1.5 mm, the distance between two infrared sensing wires within the probe. Its unit of measure is the mega pascal (MPa). Young's modulus (E) increases with a higher elasticity, indicating that skin elasticity was improved.
For evaluation of dermal density improvement, an ultrasonographic DUB® SkinScanner (Tpm Taberna Pro Medicum GmbH, Lüneberg, Germany) was applied. After applying ultrasonography gel, 3 cm from the outer corner of left eye was measured by using the probe at a right angle with skin and pressing skin with same pressure. The range of analysis was set in limits from epidermis to upper subcutaneous fat layer. The value increases with a higher density of dermis, indicating that dermal density was improved.
For evaluation of skin tone improvement, a CR-2600D spectrophotometer (Konica Minolta, Inc., Tokyo, Japan) was used. The right cheek was measured three consecutive times, and the average value was determined. The L* and a* of three measurement values were determined as a measure of skin tone. L* indicates brightness, a* indicates red and b* indicates yellow.
During the trial period, medical doctors (Dr Kyu Joong Ahn and Dr Hyung Jin Hahn) determined using a visual inspection whether subjects had any visual dermatological side-effects (including erythema, edema and scaling) or not. We indicated the degree of symptoms and reported the results. A survey was conducted to ask subjects about abnormal skin responses.
The data were analyzed using paired t-tests with SPSS 17.0 software for Windows (SPSS, Inc., Chicago, IL, USA). P<0.05 was considered to indicate a statistically significant result.
No subjects discontinued their participation due to lack of effectiveness or adverse events. The average age of the 20 female subjects was 45.60±8.18 years (data not shown). On average, the subjects used 80–98% of the quantity of test materials expected (data not shown).
There were no abnormal responses, including allergic contact dermatitis or irritant contact dermatitis, following application of the test material on the subjects, and the survey answered by subjects resulted in no special abnormal skin response for this trial period (data not shown).
The results of the evaluation of the facial wrinkles using the wrinkle value (Ra) obtained using the PRIMOS Lite are shown in
The evaluation results of the wrinkle value (Ra) showed a 5.97% decrease after 2 weeks of the test material application and a 14.07% reduction after 4 weeks of application in comparison of pre-application. The results were statistically significant (P<0.05).
The representative 3D images before application and after 4 weeks of the test material application were shown in
Next, we have determined the skin elasticity improvements with the DermaLab USB elasticity probe (
The evaluation results of skin elasticity showed 6.85 and 8.79% increase after 2 and 4 weeks of test material application, respectively, in comparison with pre-application skin. The results were statistically significant (P<0.05) and suggest that the facial cream and eye cream contribute to improve skin elasticity.
The dermal density improvements were evaluated using the DUB® SkinScanner (
The dermal density evaluation results showed 16.75 and 27.64% increase after 2 and 4 weeks of test material application, respectively, in comparison of pre-application. The results were statistically significant (P<0.05) and indicate that the facial cream and eye cream tested here improves dermal density.
The evaluation results of skin tone (L* and a* values) improvement obtained with the spectrometer are shown in
As shown in
Cosmetic formulations containing palmitoyl peptides,
Thus, formulations containing palmitoyl peptides,
This study was supported by a grant of the Korean Health Technology R&D Project (grant no. HN13C0075), administered by the Ministry of Health & Welfare of the Republic of Korea.
Improvement rates of skin wrinkle values after applying test materials. Data were presented as means ± standard deviation. A paired t-test was performed to determine statistical significant results. *P<0.05, vs. the control.
Representative 3D images of an area around the right eye. The outer corner of the right eye was measured three consecutive times using the PRIMOS Lite equipment. 3D images before and after 4 weeks of test material application are shown.
Improvement rates of skin elasticity after applying test materials. Data were presented as means ± standard deviation. A paired t-test was performed to determine statistical significant results. *P<0.05, vs. the control.
Improvement rates of dermal density after applying test materials. Data were presented as means ± standard deviation. A paired t-test was performed to determine statistical significant results. *P<0.05, vs. the control.
Improvement rates of L* value after applying test materials. Data were presented as means ± standard deviation. A paired t-test was performed to determine statistical significant results. *P<0.05, vs. the control.
Improvement rates of a* value after applying test materials. Data were presented as means ± standard deviation. A paired t-test was performed to determine statistical significant results. *P<0.05, vs. the control.
Changes in skin wrinkle values (Ra) after applying test materials.
Application period | Wrinkle values | P-value |
---|---|---|
Pre-application | 42.58±12.09 | |
2 weeks | 40.04±11.32 | 0.043 |
4 weeks | 36.59±8.15 | 0.001 |
Results presented as the mean ± standard deviation.
P<0.05
P<0.001.
Changes in skin elasticity after applying test materials.
Application period | Skin elasticity (MPa) | P-value |
---|---|---|
Pre-application | 12.85±2.55 | |
2 weeks | 13.73±2.36 | 0.045 |
4 weeks | 13.98±1.67 | 0.013 |
Results presented as the mean ± standard deviation.
P<0.05.
Changes in dermal density after applying test materials.
Application period | Dermal density | P-value |
---|---|---|
Pre-application | 42.87±7.35 | |
2 weeks | 50.05±9.81 | 0.001 |
4 weeks | 54.72±14.67 | 0.000 |
Results presented as the mean ± standard deviation.
P<0.01
P<0.001.
Changes in L* value after applying test materials.
Application period | L* value | P-value |
---|---|---|
Pre-application | 64.34±2.97 | |
2 weeks | 65.44±2.27 | 0.007 |
4 weeks | 65.72±2.71 | 0.001 |
Results presented as the mean ± standard deviation.
P<0.01.
Changes in a* value after applying test materials.
Application period | a* value | P-value |
---|---|---|
Pre-application | 10.61±2.11 | |
2 weeks | 9.50±1.76 | 0.001 |
4 weeks | 8.23±2.16 | 0.000 |
Results presented as the mean ± standard deviation.
P<0.01
P<0.001.