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Keywords:

  • photodamaged skin;
  • oil;
  • moisturizer;
  • vitamin A;
  • antioxidant

Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

Background

Cumulative lifetime sun exposure is accepted as having a very important role to play in the expression of the signs of photoaging, which is then superimposed on the intrinsic processes involved in the chronological aging of skin. Many groups have evaluated the effects of emulsion-based products, mostly although not exclusively, on the face using a variety of actives including retinoids and antioxidants. Nevertheless, the effect of a topical anhydrous product on photodamaged skin has not been reported in the literature.

Aims

The objective of this study was to clinically evaluate the effect of a vitamin A palmitate and antioxidant-containing oil-based moisturizer on facial, neck, decolletage, arms, and lower leg body sites.

Methods

In a randomized, controlled and efficacy grader-blinded clinical study conducted over 12 weeks, while at the same time recording the changes in skin condition for a no-treatment group over the same time period, live clinical expert grading of all body sites and also grading of photographs for the face and neck assessed changes in the signs of photodamage was performed for the treatment and no-treatment groups.

Results

Compared to the no-treatment group, and to baseline, the oil improved fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, roughness, firmness, and clarity of the skin on the face and neck and was also shown to improve crepey skin texture, dryness, scaling and roughness on the decolletage, arms and lower legs at the primary end point at 12 weeks (P < 0.001). Moreover, improvements in a variety of parameters were observed as quickly as 2 weeks. In general, the degree of improvement was greatest in the order legs > arms > decolletage > face > neck.

Conclusions

Collectively, these results show the cumulative improvements in the signs of photoaging compared to a no-treatment control group for the oil-based antiaging moisturizer for the first time. The differences in the efficacy of the vitamin A palmiate and antioxidant oil-based moisturizer on different body sites probably reflect the differences in likely photodamage.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

There is increasing evidence documenting the effects of ‘antiaging’ cosmetic moisturizers on the signs of photodamaged skin. Typical agents used in these moisturizers include hydroxyacids,[1, 2] retinol, and its esters,[3, 4] salicyloylphytosphingosine,[5] peptides,[6-9] adenosine,[10] niacinamide,[11] creatine and folic acid,[12] peroxisomal proliferator activated receptor agonists,[13] hyaluronic acid fragments,[14] and a variety of antioxidants including ascorbic acid[15] and lipoic acid.[16] Many of these agents have complex effects on the skin ranging from increasing dermoepidermal membrane restructuring through to inhibition of matrix metalloprotease activity and improving epidermal differentiation all of which are perturbed in photodamaged skin. However, these improvements are usually expressed to the consumer as reduced number and/or depth of wrinkles, more even skin tone, reduced hyperpigmentation together with smoother, firmer, and more luminous skin.

Until recently, however, the relative effects of these actives were considered to be inferior to the effects of retinoic acid. Nevertheless, the use of a niacinamide, peptide, retinyl propionate product regime was found to be as effective as that of retinoic acid in alleviating the signs of skin photodamage.[17] Importantly, although, all these treatments, including the retinoic acid prescription products, are emulsion-based products and as far as we are aware there is no reported study of the effect of a totally anhydrous cosmetic antiaging moisturizing oil alleviating the signs of skin photodamage.

Antioxidants and retinyl palmitate were included in the oil for their potential effect in alleviating the signs of skin photodamage. However, as it has been reported recently, in a longitudinal study that simply having a drier cheek stratum corneum (SC) was predictive of more persistent skin wrinkling 8 years later,[18] we considered that the simple moisturizing effect of the anhydrous moisturizing oil would also be effective in the treatment of aged skin. To demonstrate its effectiveness, we performed a randomized, controlled and efficacy grader-blinded clinical study examining the changes in skin condition of the face, neck, décolletage, lower legs, and the arms over a 12-week period compared to a no-treatment control group. We believe this is the first report of its kind demonstrating the improvements in the signs of skin photodamage of a cosmetic anhydrous antiaging moisturizing oil on both facial and body skin sites while at the same time recording the changes in skin condition for a no-treatment group over the same time period.

Methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

Clinical design

Seventy-three healthy, but photodamaged women volunteers were recruited into this study and randomly designated into a treatment or a no-treatment group. Subjects had mild-to-moderate photodamage with starting grades between approximately 4–5 on a 9-point grading scale. There were no differences in baseline scores between the two groups. Of these 35 subjects completed the treatment cell and 32 subjects completed the no treatment cell and were available for per-protocol analysis. A summary of the subject demographics is given in Table 1.

Table 1. Summary of demographic information – PP population
 Treated groupUntreated group
N 3532
Age (years)
Mean52.556.4
SD9.18.9
Minimum3032
Maximum6670
  n (%) n (%)
Ethnicity/race
African American1(2.9)
Asian4(11.4)2(6.3)
Caucasian28(80.0)27(84.4)
Hispanic2(5.7)3(9.4)

Prior to the start of the study subjects participated in a screening evaluation and only used a mild syndet bar for cleansing. During this time, subjects did not apply any cosmetic products. Subjects in the treatment group were instructed on the use of their product with daily and evening application for 12 weeks to their entire face, neck, décolletage, outer arms, and lower legs. Subjects used five drops of the oil (0.2 g) on their face and neck for each application while the amount used on other body parts was ad libitum, but subjects were instructed to use the same amount each time. The composition of the product is given in Table 2.

Table 2. Product composition
Mineral Oil, Triisononanoin, Cetearyl ethylhexanoate, isopropyl myristate, Bisabolol, Tocopherol acetate, Retinyl palmitate, Calendula oil, Rosemary oil, Chamomile oil, BHT, Perfume

Subjects cleansed their face, removed all makeup and jewelry, and acclimated in a temperature and humidity controlled area (20 ± 2 °C and 37 ± 2% relative humidity) for at least 30 min within the clinic prior to grading and photography procedures.

On the assessment days, subjects applied the cosmetic oil at least 10–16 h before grading commenced. Subjects were clinically graded on the separate body sites for overall appearance, fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, visual and tactile roughness/smoothness, firm appearance, and clarity (dullness) on the face and neck. On the décolletage, arms and lower legs overall appearance, crepey texture, dryness/scaling and visual and tactile roughness, and smoothness were clinically graded. The grading used a modified Griffiths et al. photonumeric scale for photodamaged skin. The scale ranges from 0 to 9, where 0 represents no evidence of photodamage and nine represents the most severe photoaging on each parameter. Half-point scores were used as required to better describe the clinical condition. All subjects were monitored for the occurrence of adverse events. Written informed consent for participation in this study was provided by all subjects in accordance with the Helsinki II declaration. The trial was conducted following all applicable guidelines for the protection of human subjects for research as outlined in 21 CFR 50, in accordance with the accepted standards for Good Clinical Practices (GCPs), International Conference on Harmonization (ICH) and the standard practices of Thomas J. Stephens & Associates, Inc.. The study was conducted from September 7th 2011 to December 17th 2011 in Dallas USA.

Digital photography

Photographs were also taken of each subject's face and neck (right side, left side and center view) for expert grading. Subjects were provided with a black matt headband to keep hair away from the face and instructed on proper headband placement. A matt gray cloth was draped over subject's clothing and tucked down over the collar so that the neck was clearly visible and the subject's clothing was not showing. Subjects' hands were placed in their lap or arms were placed at their sides. The background consisted of a black matte cloth positioned approximately 1 m behind the subject.

Subjects were carefully positioned for each photograph, either directly facing the camera for the centre view or turned at a 45° angle for the right and left side views. Subjects were instructed to adopt neutral, nonsmiling expressions with their eyes open. A Casmatch color chart (Bear Medic Corporation, Chiba, Japan) and mini color checker chart (X-Rite, Elmsford, NY, USA) were contained within each photograph.

Digital photographs were taken from each subject using the Stephens & Associates' photo-station with a 12.3 megapixel Nikon D300 digital SLR camera (ISO 200, shutter speed 1/200 s) equipped with a 70–180 mm Micro-NIKKOR lens at f/16. Visible light (unfiltered full-spectrum [white] light) was provided using comet studio strobes affixed to the photo-station, which were not moved during the study.

The visible light photographic images taken during the study were graded for overall appearance, fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, and clarity (dullness) (using the scales specified for efficacy grading) overall on the face and neck.

Statistical analysis

The per-protocol population was the primary population for all statistical analysis i.e. only data of completing subjects were analyzed. Live and photographic grading were analyzed using nonparametric statistical methods. A Friedman test and Wilcoxon signed-rank tests were used for the change from baseline whereas a pairwise Wilcoxon rank sum test was used for comparison between the groups. A Bonferroni correction was used to compare between weeks 2, 4, & 8. A Fishers exact test was used to compare the number of subjects that were improved between the two treatments. All statistical tests were two-sided at significance level α = 0.05 and the statistical analyses were performed using SAS software version 9.20 series (SAS Statistical Institute, Cary, NC, USA). Mean change from baseline, mean percentage change and percentage of subjects improved or worsened was calculated at each postbaseline time point.

Results

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

Of the 73 subjects enrolled, 35 in the treatment group and 32 in the untreated group completed the study. Five of these subjects withdrew due to not related or unlikely reasons with the use of the product. Only one subject withdrew with a possible relationship with the product. The total amount of product used over the different body sites is shown in Table 3.

Table 3. Summary statistics for amount of test material used per subject
Average (g)140.60
Standard Deviation (g)71.68
Minimum (g)49.52
Median (g)128.24
Maximum (g)381.12

Efficacy grading and photographic grading face and neck

Face

Use of the anhydrous cosmetic antiaging oil, caused a statistically significant improvement in scores for all clinically graded efficacy parameters (overall appearance, fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, visual roughness/smoothness, tactile roughness/smoothness, firm appearance, and clarity) on the face after 8 and 12 weeks of use when compared with baseline scores (Table 4). In addition, all parameters except firm appearance showed a significant improvement in scores at week 4. Parameters (overall appearance, fine lines, visual and tactile roughness/smoothness, and clarity) had a significant improvement in scores at the week 2 time point compared to baseline. For subjects assigned to the no treatment cell, there was a statistically significant improvement in scores for tactile roughness/smoothness at week 8 compared to baseline scores otherwise there were no other differences.

Table 4. Summary of change from baseline results and treatment comparison for efficacy grading – face
 Average change from baseline and comparisons to baselineOverall P-value calculated from Friedman Test
Week 2Week 4Week 8Week 12
TreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treated
  1. For all parameters, improvement is shown by a decrease in scores.

  2. a

    Indicates a statistically significant improvement (P < 0.05) from baseline.

  3. b

    Indicates a statistically significant improvement (P < 0.01) from baseline.

  4. c

    Indicates a statistically significant improvement (P < 0.001) from baseline.

  5. d

    Indicates a statistically significant improvement (P < 0.05) of Bio-Oil compared to no treatment.

  6. e

    Indicates a statistically significant improvement (P < 0.01) of Bio-Oil compared to no treatment.

  7. f

    Indicates a statistically significant improvement (P < 0.001) of Bio-Oil compared to no treatment.

Overall appearance−0.13a,e0.00−0.36c,f−0.02−0.56c,f−0.09−0.77c,f−0.02<0.0010.379
Fine lines−0.21c,d−0.05−0.51c,f0.00−0.76c,f−0.05−0.86c,f0.03<0.0010.547
Coarse wrinkles−0.04d0.03−0.11a−0.02−0.31c,f0.06−0.36b,f0.09<0.0010.733
Mottled pigmentation0.000.00−0.14b,e0.02−0.31c,f0.00−0.49c,f0.00<0.0010.489
Uneven skin tone−0.060.00−0.27c,f−0.02−0.43c,f0.00−0.64c,f−0.05<0.0010.805
Visual roughness−0.27c,f−0.03−0.53c,f0.00−0.84c,f−0.08−1.07c,f−0.09<0.0010.222
Tactile roughness−0.40c,e−0.06−0.64c,f−0.1−0.93c,f−0.23a−1.13c,f−0.19<0.0010.002
Firm appearance0.000.03−0.060.02−0.20c,f0.02−0.30c,f0.03<0.0010.921
Clarity (dullness)−0.20c,f0.08−0.50c,f0.05−0.71c,f−0.02−0.80b,f0.02<0.0010.238

Analysis of the change from baseline between the treated and untreated groups indicated a statistically significant improvement in the majority of parameters at week 2 and week 4, and in all parameters at week 8 and week 12 for the treatment compared to the untreated cell (Fig. 1).

image

Figure 1. Summary of treatment comparison results for efficacy grading - face.

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Clinical grading of photographic images confirmed the live grading results. The treated group had a statistically significant improvement in scores for all graded parameters (overall appearance, fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, and clarity) on the face after 8 and 12 weeks of use when compared with baseline scores. For subjects assigned to the no treatment cell, grading of photographic images of the face did not indicate any statistically significant differences at any postbaseline time point compared to baseline scores. Analysis of the change from baseline between the treated and untreated groups indicated a statistically significant improvement in all graded parameters at week 2 through week 12, with the one exception of coarse wrinkles, which did not indicate a significant difference between cells at weeks 2 and 4 (not shown).

Typical improvements in the signs of the wrinkle and mottled hyperpigmentary aspects of photodamage can be seen in Figure 2.

image

Figure 2. (a) Typical improvements in eye wrinkles following treatment. (b) Typical improvements in mottled hyperpigmentation following treatment.

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Neck

Use of the oil, caused a statistically significant improvement in scores for all clinically graded efficacy parameters (overall appearance, fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, visual roughness/smoothness, tactile roughness/smoothness, firm appearance, and clarity) on the neck after 8 and 12 weeks of use when compared with baseline scores. In addition, all parameters except coarse wrinkles showed a significant improvement in scores at week 4, and four parameters (overall appearance, visual and tactile roughness/smoothness, and clarity) had a significant improvement in scores at the week 2 time point compared to baseline (Table 5). For subjects assigned to the no treatment cell, there was a statistically significant improvement in scores for tactile roughness/smoothness at week 12 compared to baseline scores.

Table 5. Summary of change from baseline results and treatment comparison for efficacy grading – neck
 Average change from baseline and comparisons to baselineOverall P-value calculated from Friedman Test
Week 2Week 4Week 8Week 12
TreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treated
  1. For all parameters, improvement is shown by a decrease in scores.

  2. a

    Indicates a statistically significant improvement (P < 0.05) from baseline.

  3. b

    Indicates a statistically significant improvement (P < 0.01) from baseline.

  4. c

    Indicates a statistically significant improvement (P < 0.001) from baseline.

  5. d

    Indicates a statistically significant improvement (P < 0.05) of Bio-Oil compared to no treatment.

  6. e

    Indicates a statistically significant improvement (P < 0.01) of Bio-Oil compared to no treatment.

  7. f

    Indicates a statistically significant improvement (P < 0.001) of Bio-Oil compared to no treatment.

Overall appearance−0.10a,d0.03−0.34c,e−0.09−0.51c,f−0.11−0.66c,f−0.08<0.0010.006
Fine lines−0.13d0.02−0.29c,f0.02−0.46c,f−0.02−0.54c,f0.00<0.0010.760
Coarse wrinkles−0.010.00−0.09d0.00−0.14b,e0.00−0.16c,e−0.02<0.0010.406
Mottled pigmentation0.000.00−0.14b,e−0.02−0.27c,f−0.02−0.37c,f−0.05<0.0010.073
Uneven skin tone−0.010.00−0.27c,f−0.03−0.41c,f−0.03−0.47c,f−0.09<0.0010.204
Visual roughness−0.29c,f0.06−0.50c,f−0.02−0.76c,f−0.06−0.89c,f−0.06<0.0010.033
Tactile roughness−0.34c,f0.02−0.59c,f−0.06−0.87c,f−0.13−1.10c,f−0.22a<0.0010.008
Firm appearance−0.010.02−0.11a,e0.02−0.19c,f0.02−0.29c,f0.03<0.0010.287
Clarity (dullness)−0.21c,f0.08−0.46c,f0.00−0.56c,f−0.02−0.61c,f−0.05<0.0010.092
Table 6. Summary of change from baseline results and treatment comparison for efficacy grading – decolletage, legs, arms
 Average change from baseline and comparisons to baselineOverall P-value calculated from Friedman Test
Week 2Week 4Week 8Week 12
TreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treatedTreatedUn-treated
  1. For all parameters, improvement is shown by a decrease in scores.

  2. a

    Indicates a statistically significant improvement (P < 0.05) from baseline.

  3. b

    Indicates a statistically significant improvement (P < 0.01) from baseline.

  4. c

    Indicates a statistically significant improvement (P < 0.001) from baseline.

  5. d

    Indicates a statistically significant worsening (P < 0.05) from baseline.

  6. e

    Indicates a statistically significant worsening (P < 0.01) from baseline.

  7. f

    Indicates a statistically significant worsening (P < 0.001) from baseline.

  8. g

    Indicates a statistically significant improvement (P < 0.05) of Bio-Oil compared to no treatment.

  9. h

    Indicates a statistically significant improvement (P < 0.01) of Bio-Oil compared to no treatment.

  10. i

    Indicates a statistically significant improvement (P < 0.001) of Bio-Oil compared to no treatment.

Décolletage
Overall appearance−0.11g0.02−0.34c,i−0.03−0.50c,i−0.11−0.83c,i−0.09<0.0010.025
Crepey texture−0.23b,i0.02−0.41c,i−0.03−0.64c,i−0.05−1.14c,i−0.06<0.0010.142
Dryness/ scaling−0.29c,i0.03−0.64c,i−0.05−0.79c,i−0.13−1.26c,i−0.09 <0.0010.161
Visual roughness−0.24c,h0.00−0.49c,i−0.06−0.74c,i−0.11−1.00c,i−0.09<0.0010.046
Tactile roughness−0.36c,i−0.03−0.61c,i−0.09−0.83c,i−0.16−1.11c,i−0.13<0.0010.003
lower legs
Overall appearance−0.26c,i0.16−0.43c,i0.08−0.57c,i0.19−0.94c,i0.25d<0.0010.070
Crepey texture−0.23c,i0.11−0.39c,i0.13−0.63c,i0.33e−1.10c,i0.42f<0.001<0.001
Dryness/ scaling−0.39c,i0.19−0.60c,i0.36d−0.79c,i0.42e−1.37c,i0.66f<0.0010.004
Visual roughness−0.41c,i0.18−0.56c,i0.19 −0.79c,i0.31d−1.16c,i0.47f<0.0010.005
Tactile roughness−0.41c0.21−0.59c0.30d−0.79c0.42e−1.10c0.59f<0.001<0.001
Arms
Overall appearance−0.19c,i0.05−0.39c,i0.02 −0.56c,i0.02−0.80c,i0.03<0.0010.855
Crepey texture−0.26c,i0.05−0.49c,i0.05−0.77c,i0.08−1.36c,i0.06<0.0010.927
Dryness/scaling−0.31c,i0.06−0.69c,i0.09−0.84c,i0.08−1.33c,i0.33<0.0010.265
Visual roughness−0.34c,i0.08−0.57c,i0.08−0.81c,i0.13−1.07c,i0.17d<0.0010.088
Tactile roughness−0.41c,i0.02−0.63c,i−0.06−0.80c,i0.00−1.07c,i0.14<0.0010.142

Analysis of the change from baseline between the groups indicated a statistically significant improvement in the majority of parameters at week 2 and in all parameters at week 4, week 8, and week 12 for the treatment cell compared to the untreated cell (Fig. 3).

image

Figure 3. Summary of treatment comparison results for efficacy grading - neck.

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Clinical grading of photographic images indicated that the test product caused a statistically significant improvement in scores for overall appearance, fine lines, coarse wrinkles, uneven skin tone, and clarity) on the neck after 8 and 12 weeks of use when compared with baseline scores. For subjects assigned to the no treatment cell, grading of photographic images of the neck did not indicate any statistically significant differences at any postbaseline time point compared to baseline scores. Analysis of the change from baseline between the treatment cell and untreated cell indicated a statistically significant improvement in all graded parameters for the treatment cell compared to the untreated cell at week 4, week 8, and week 12, with the one exception of mottled pigmentation which did not indicate a significant difference between cells at the week 4 time point (not shown).

The percentage of subjects showing improvement in the Bio-Oil treatment cell (percentage of responders for whom Bio-Oil was efficacious) was calculated for each postbaseline time point for all parameters. The percentage of subjects improved was 94.3% on the face and 80% on the neck both of which were significant (P < 0.001)

Other body sites

Use of the treatment product caused a statistically significant improvement in scores for all clinically graded efficacy parameters (overall appearance, crepey texture, dryness/scaling, visual roughness/smoothness, and tactile roughness/smoothness) on the décolletage, lower legs, and arms after 4, 8, and 12 weeks of usage when compared to baseline scores (Table 6). In addition, there was a statistically significant improvement in all parameters at each location after 2 weeks of usage, with the exception of overall appearance on the décolletage, which did not indicate any statistically significant changes. For subjects assigned to the no treatment cell, there was a statistically significant worsening in efficacy clinical grading scores for all parameters on the lower legs and for visual and tactile roughness/smoothness at week 12 when compared to baseline scores.

Analysis of the change from baseline between the treatment cell and untreated cell indicated a statistically significant improvement in all parameters at each grading location for the treatment cell compared to the untreated cell at week 2, week 4, week 8, and week 12 (Figs 4-6).

image

Figure 4. Summary of treatment comparison results for efficacy grading - decolletage.

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image

Figure 5. Summary of treatment comparison results for efficacy grading - Lower legs.

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image

Figure 6. Summary of treatment comparison results for efficacy grading - Arms.

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At week 12, the percentage of subjects that showed an improvement in clinical scores on the décolletage, lower legs and arms was 88.6% in all sites (P < 0.001).

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

To our knowledge, this is the first study demonstrating the effect of a cosmetic anhydrous antiaging moisturizing oil on the signs of photodamage on the face, neck, décolletage, arms, and lower legs. Compared to the no-treatment group, and to baseline, the oil improved fine lines, coarse wrinkles, mottled pigmentation, uneven skin tone, roughness, firmness and clarity of the skin on the face and neck and was also shown to improve crepey skin texture, dryness, scaling and roughness on the décolletage, arms and lower legs. The efficacy of the product appeared to be greater for the face compared with the neck for improvements in wrinkling scores, but similar for the skin color problems. This relative responsiveness on the different body sites would appear to be similar in other clinical studies using intense pulsed light.[19] Grading of the photographs supported the live grading results. The roughness and dryness improvements were easier to treat on the legs than on the arms and the décolletage suggesting greater photodamage to the latter body site and thereby less responsiveness to treatment. In general, the décolletage appeared to be more difficult to treat and appeared to behave similar to the face and neck in terms of skin grading improvements. The neck was slightly harder to treat in terms of grading. In terms of overall numbers of subjects that improved on the face, neck, décolletage, legs and arms 94.3%, 80%, 88.6%, 88.6%, and 88.6% of subjects improved whereas only 25%, 31%, 25%, 15.6%, and 21.9% of subjects improved in the no treatment group.

The study was a grader-blind study and all product treatments were stopped 10–16 h before any skin assessments were made. The consistency in improvements in skin condition for all body sites implies the cosmetic oil can dramatically improve the signs of photodamaged skin. Similar effects can be also observed from the emulsion-based vehicle treatment groups for other reports,[1-17] but this study compares the improvements in photodamage to a no-treatment control group for the first time. As can be observed cumulative improvements are found with increasing treatment on all body sites.

The SC has been proposed to play an important role in wrinkle formation and indeed having a drier cheek SC has been shown to be predictive of more persistent wrinkling over an 8-year period.[18] Fine wrinkle formation has been linked to the dryness of the SC and increased expression of fine wrinkles are observed in low humidity compared with high humidity environments.[20] Moreover, its water holding capacity and elasticity decreases after repetitive UV exposure making it prone to wrinkle formation.[21] Decreases in SC levels of filaggrin and natural moisturizing factors are known on photodamaged skin sites, which will reduce its mechanical properties.[22] Deterioration in the fibrous ultrastructure of the keratin intermediate filaments has been reported to be caused by repetitive UVB irradiation associated with an increased skin wrinkling.[23] Changes in keratin patterns have been followed after UV irradiation and increased expression of K6 and K16 were apparent.[24, 25] As these keratins are not as mechanically resilient as the normal K1/K10 pair, then these have also been associated with a loss in the elasticity of the epidermis. All these events are associated with a less flexible and more brittle SC. Moreover, computational models have been developed that show a decrease in SC modulus by 50% is likely to reduce wrinkle formation.[26] This level of improvement in skin elasticity may be expected following moisturization of the skin, but equally lessening repetitive stress after moisturization may allow repair of wrinkles already formed.

Photoaged skin contains significantly fewer levels of basement membrane molecules at the dermoepidermal junction between the epidermis and dermis, such as collagens, fibrillins, and glycosaminoglycans etc., which are believed in part due to increased cutaneous expression of MMPs.[27] These changes are likely initiated from the increased oxidative stress from the solar irradiation and the consequent activation of aberrant transcription factor signaling pathways, such as increased AP-1 and NfκB, which also lead to increased levels of inflammatory cytokines.[28] Simple moisturization by occlusion, the primary mechanism of action of the oil used in this study, is likely to dampen these responses. Changes in epidermal cytokines are known in a variety of model systems. For instance, occlusion significantly decreased the epidermal expression of the profibrotic cytokine interleukin-1 beta and increased the epidermal expression of the antifibrotic cytokine tumor necrosis factor alpha in a rabbit hypertrophic scar model, a wrinkle has been considered to be a solar scar. These alterations in the epidermal gene expression also resulted in concomitant changes in the expression of the transforming growth factor-beta family members by cells in the dermis, resulting in a decrease in profibrotic signaling within the dermis.[29-31]

Nevertheless, improvements in skin aging biology are expected from the use of some of the ingredients in the product. Retinoic acid after it conversion from retinyl palmitate may be acting on the retinoic receptors.[32] Alternatively retinyl palmitate with its UV radiation absorbing capacity or acting as an antioxidant together with other antioxidants in the oil may be contributing to the benefit.[33] Vitamin E acetate is used in oil but it is widely known that it needs to be hydrolysed to free tocopherol to deliver its effects. This is known to occur only after several days of application and after its penetration into skin.[34] Most recently, it has been shown to reduce protein carbonyls in the skin but that the acetate has less activity than the free tocopherol.[35] Nevertheless, the acetate is used for product stability reasons. Bisabolol is another antioxidant in the product, which has been shown to reduce skin pigmentation.[36] This together with the other ingredients may be helping in the reduction in mottled hyperpigmentation throughout the study.

However, this study was not designed as a vehicle-controlled study and as such; we cannot ascribe the efficacy of the moisturizing oil to any of its particular ingredients. Nevertheless, there is no reason to suspect that the vitamin A ester or other antioxidants would not be efficacious in a totally anhydrous oil format as they are in emulsion-based products. The product was effective not only compared to its own baseline but also to a no-treatment control group (which was primarily used to evaluate any potential changes in the environmental conditions during the time course of the study). We believe that the changes observed between the treatment and the no-treatment control group are real and that the changes observed in the treatment group are not just an emollient effect from the oil. The last application of the product in the treatment group was the evening before any assessment and subjects had also cleansed their skin the morning before any assessment thereby minimizing the presence of any likely residual oil that would mask any of the signs of aging. This is further corroborated by the cumulative improvements in the parameters graded for the signs of skin aging. This cumulative effect would not have been apparent if this was not the case.

Irrespective of the potential mechanisms of action, these studies provide the first evidence that the use of a cosmetic anhydrous antiaging moisturizing oil is able to provide a clinically identifiable improvement in the appearance of the signs of photodamaged skin. Not only that, differences in the relative performance occurs on different body sites with the arms and legs being easier to treat than the décolletage, neck and face probably due to the differences in levels of skin photodamage across these body sites.

Acknowledgments

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References

This study was fully funded by Union Swiss and conducted independently at Thomas J. Stephens & Associates Inc. Professor AV Rawlings is a consultant to Union Swiss.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. References