A holistic natural plant extract to minimize the appearance of stretchmarks on the body and wrinkles on the face

During the Covid-19 pandemic period, the level of sedentary lifestyle reached records. Eating habits changed (1, 2). With documented tendencies to gain weight, the probability to get stretchmarks increased. The change in aesthetic may generate a decrease of self-esteem, and the need to have an efficient solution against stretchmarks is real yet challenging to achieve in-vivo. Another parameter affecting loss of self-esteem is the perception of skin aging, the most visible signs of which are periocular wrinkles: therefore, keeping a youthful and luminous face to renew a positive mindset gains additional relevance. The need for highly efficient anti-wrinkle effects is well and truly present. We developed a plant extract based on a poppy seed extract, RP-SE and tested it in two in-vivo studies. In the first one, RP-SE was tested for its ability to lessen the visibility of stretchmarks. In the second study, male and female volunteers with visible wrinkles on crow’s feet were recruited, and the effects of RP-SE on wrinkles and the dermis thickness were investigated. In this publication, we present and discuss the results of these two in-vivo studies.

The flowers of Papaver rhoeas are cultivated in France according to sustainable principles. The seeds are ultimately used for the extraction process. The extract of Papaver rhoeas seeds was obtained via an Ethanol/CO2 co-extraction (super-critical CO2 extraction). The supercritical status of CO2 represents a well-established green process and a preferred extraction medium in comparison to conventional solvents (4). The ethanol is removed by vacuum evaporation. Afterwards the oil extract is clarified by filtration and conditioned under inert atmosphere. Under given process conditions a standardized extract of Papaver rhoeas is available to us. The lead component of the extract is linoleic acid in a concentration range between 69 – 85 %. Other components include oleic acid, palmitic acid and further saturated fatty acids bound or in free form.

In order to obtain a ready-to-use, easy-to-formulate cosmetic active ingredient, the poppy seed extract is then mixed with a suitable cosmetic oil (INCI: Caprylic/Capric Triglyceride). The final ingredient RP-SE is a clear oil containing 10 % of Papaver rhoeas extract.

A 56-day double blind, placebo controlled in-vivo study was conducted. 24 Caucasian female volunteers, >18 years old having given their written consent were recruited. The volunteers were in postpartum phase having at least two recent stretchmarks on each side of the body (less than 6 months) pink and comparable on the stomach, the buttocks and the thighs.

The volunteers applied an emulsion containing 1% RP-SE (Papaver rhoeas extract) (see Table 1) and the placebo (same basis formulation without any skin care active ingredient) twice daily on the selected stretchmarks and surrounding during 56 days with a slight massage until complete absorption of the test products. The application zones of the study products were randomized. Statistical analysis was done using Shapiro-Wilk test, then paired student t-test or Wilcoxon Signed rank test according to the results of the normality test.

The following read out parameters were explored: centimetric measurements, colorimetric measurements (L*a*b* values) using a MINOLTA CM700-d spectrophotometer®, illustrative pictures (Nikon® D90 and SONY® A6600) and a self-evaluation using a questionnaire.

A 56-day double blind, placebo controlled in-vivo study was conducted. 47 Caucasian volunteers (male and female) aged 45-65 years, having visible wrinkles/fine lines on crow’s feet were involved in this study.

The volunteers divided into 2 groups, applied 3 test products on hemi-faces: all the same bases o/w emulsions were used; the placebo with no additional active ingredient and tested by 23 subjects; the verum containing 2% RP-SE, tested by 47 subjects; and the comparator containing a commercially available poppy oil at 2%.

The following read-out parameters were explored: anti-wrinkles effects on crow’s feet by studying directly in-vivo the cutaneous relief parameters Ra, Rt and Rz using Dermatop®, and re-densifying effect by studying the collagen density on the cheeks using SIAscope® SiametricsTM. Illustrative pictures were taken using the Colorface® device.

Significant decreases in the average measurements of the stretchmark length and width after 56 days could be observed for both test products: respectively -8% (p = 0.0005) and -19% (p=0.0002) for RP-SE (positive outcome reported in 68% of the subjects), and respectively -10% (p<0.0001) and -17% (p=0.002) for the placebo after 56 days of use (positive outcome reported in 58% of the subjects) (Figure 1).

Spectrophotometer measurements showed significant increases of the lightness (L* value) for both emulsions containing 1% Papaver rhoeas seed extract (RP-SE) and placebo respectively by +5% (p=<0.0001) L* >3 A.U.) and +4% (p=0.0045); L* value < 3 A.U.).

The redness value (a*) significantly decreased by -21% (p<0.0001) after application of the emulsion containing 1% RP-SE and by -12% (p=0.0006) for the placebo after 56 days of use.

The statistical comparisons between both products showed a statistical significance in favor of RP-SE regarding the redness decrease (p=0.0323) after 56 days and a tendency in favor of RP-SE regarding the lightness parameter (p=0.1128) (Figure 2).

Furthermore, illustrative pictures taken during this in-vivo study (see representative examples shown in Figure 3) fit well with these tendencies observed for 1% RP-SE. The overall appearance of the stretchmarks is minimized.

Finally, the subjective questionnaire indicated for multiple parameters, the preference of the volunteers for the emulsion containing 1% RP-SE (Figure 4).

Getting visible and measurable effects as well as a statistically significant difference between active and placebo formulations in an anti-stretchmark in-vivo study is a complex task.

The outcome of our in-vivo study shows significant results for both the test product containing Papaver rhoeas seed extract (RP-SE) and the placebo product. When comparing the products, there is a statistical significance in favor of RP-SE in case of the redness reduction, and a tendency in the case of the lightness increase. The number of volunteers included is this study was the minimum required to envision getting a statistically significance difference at the different time points and between the products. This was a first proof of concept and due to the organizational complexity of such a study (and even more in Covid times) we could only include 20 subjects; the literature shows that higher number of volunteers are often recruited (5) and we might have reached significant differences between products for several endpoints, having a higher number of included subjects. The positive effect of the placebo might be attributed to the fact that the volunteers were asked to massage the stretchmarks with both products until complete absorption of the products into the skin. Some studies reflect the benefits of massage alone (6, 10).

Concerning the color of the stretchmarks, let’s remind that early stretchmarks will appear pink/reddish and correspond only to the beginning of the development of the marks (8). Such scarring shows the blood vessels through, hence the red color pops. They typically occur when the skin stretches due to the rapid increase in size of underlying structures, like it may typically be the case in pregnant women, or those who are after child delivery in the postpartum phase. Postpartum women were indeed recruited in this in-vivo study. Earlier studies undertaken with RP-SE showed its ability to increase skin elasticity in volunteers having cellulite on their thighs and/or gluteus (11). Therefore, it might explain and validate the stronger decrease of redness observed in this study in the case of treatment with RP-SE. These results also correlate well with other earlier investigations in which RP-SE at 2% use level applied on the face increased the lightness/radiance of the skin (3).

Anti-wrinkles effects could be observed after 28 days application of the emulsion containing 2% RP-SE as shown by the significant decreases of Rz and Rt parameters by -4% (p=0.0299) and -5% (p=0.0319) respectively (see Figure 5). For the Ra parameter, the decrease after application of the emulsion with RP-SE was very close to statistical significancy (decrease by -4%, p= 0.0523).

Neither the placebo, nor the emulsion containing the comparator did show any significant anti-aging effect. These results are also confirmed by illustrative pictures, and 2D/3D illustrations as shown on Figure 6.

Thickness of the papillary dermis:

The SIAscopy, intracutaneous spectrophotometric analysis, is a dermal imaging technique based on the absorbed light then reflected by the skin. The measurement depth is until 2mm under the skin. When the scanner of the SIAscope illuminates the skin, part of the light is reflected and scattered from the surface. The rest is passed in the upper layers of the skin. This incident light is absorbed by the melanin in the epidermis, then penetrates the dermis where it is absorbed by hemoglobin. Finally, it interacts with the collagen in the papillary dermis. The light returned to the skin surface is then analyzed according to the wavelengths specific to each chromophore (melanin, hemoglobin, collagen). An increased amount of reflected light corresponds to an increase of the density of collagen and therefore to an increase of the thickness of the papillary dermis. The ultimate effect is a re-densifying effect (12).

After 28 days of application, the results showed a significant increase of the reflected light by 6% (p=0.0001) and 5% (p=0.0059) for the emulsion containing 2% RP-SE and the one containing the comparative product respectively. The placebo did not show any significant increase of reflected light. It is important to note that a positive outcome after application of the emulsion containing RP-SE was measured in 80% of the volunteers, whereas a positive outcome was measured in only 57% of the subjects in the case of the emulsion containing the comparator (Figure 7). It is also important to remind that RP-SE contains only 10% of Papaver rhoeas extract whereas the commercial benchmark only contains Poppy oil. Therefore, this gives even more confidence and strength to the results obtained for RP-SE.

Aging has a detrimental effect on connective tissues in the skin, leading to declines in elastin and collagen fibers and thus resulting in fine lines and wrinkles. Procollagen I is a precursor of collagen I which is the most abundant collagen type. Skin wrinkling also progresses as dermal thickness is reduced over time as well as collagen structures (13-15).

The plumping effect observed in this new study match with existing investigations done on our Papaver rhoeas extract (RP-SE). First, in a previous in-vivo study performed on the body, we showed that RP-SE at 1% use level, improved skin density by 10% after 8 weeks of application (11). These results provide a validation of the new results obtained using the SIAscopy method. Then, in another investigation, in-vitro based, we showed that RP-SE at 0.01% increased procollagen I by 64% vs untreated and significantly better than the benchmark used (ascorbic acid 0.02%) (internal results, not published).

Our plant extract based on poppy seeds, RP-SE (INCI Caprylic/Capric Triglyceride, Papaver Rhoeas Extract (for China: Papaver Rhoeas Flower Extract), Tocopherol) was tested in two in-vivo studies. In the first one, it was tested for its ability to lessen the visibility of stretchmarks. In the second study, wrinkles and the dermis thickness were investigated.

Based on the outcome of these investigations, we could demonstrate the performance of RP-SE to minimize stretchmarks, and as an attractive anti-aging ingredient.

Stretchmarks reduction is complex to achieve and yet, RP-SE at 1% use level was able to minimize their appearance by increasing the lightness (L*), by reducing the redness (a*) significantly better than the placebo as well as decreasing the width and length of stretchmarks. These results were also well documented by illustrative pictures. Additional investigations may be undertaken for further validation (e.g., more volunteers, longer duration of the study, different emulsion base, etc…). In the case of the anti-aging study, we could show that RP-SE at 2% use level significantly decreased the average roughness (Rz) and the maximum relief amplitude (Rt) on crow’s feet, leading to visible anti-wrinkle effects, whereas the comparator based on a poppy oil did not show any measurable effect. The thickness of the papillary dermis was also increased after treatment with 2% of RP-SE. Our poppy seed extract provides a unique performance that cannot be matched by a simple commercially available poppy extract.

The authors would like to warmly thank Dr. Andrew Philip Salazar, Merck KGaA for his scientific support, as well as Eurofins-Dermscan.

Table 1. Composition of the formulations for both in-vivo studies
(anti-stretchmarks and anti-aging).

Figure 1. Centimetric measurements: Stretchmark length and width for an o/w emulsion containing 1% RP-SE and for the placebo. * p< 0.05; ** p< 0.01; *** p< 0.001 (vs. D0, t-test or Wilcoxon).

Figure 2. Spectrophotometirc measurements: Variation of the L* and a* parameters for an emulsion containing 1% RP-SE and for the placebo after 56 days. * p< 0.05; ** p< 0.01; *** p< 0.001 (vs. D0, t-test or Wilcoxon).

Figure 3. Illustrative pictures: Pictures showing evolution of stretchmarks for a selected volunteer. (a) at D0 without any treatment (b) at D56 after treatment with an o/w emulsion containing 1% RP-SE (c) without any treatment (d) after treatment with placebo (o/w emulsion).

Figure 4. Subjective evaluation questionnaire for both test products 1% RP-SE (Papaver rhoeas extract) in an emulsion and the placebo. Results >71.8% are considered as statistically significant (n=21).

Figure 5. Anti-wrinkle effect measured (by mean of Rz and Rt parameters) on volunteers having applied the placebo emulsion, the verum containing 2% RP-SE and the comparator after 28 days of use. * p< 0.05; ** p< 0.01; *** p< 0.001 (Shapiro-Wilk test and for the product comparison mixed ANOVA model).

Figure 6. Anti-aging study: exemplary photo documentation, 2D and 3D illustration on Volunteer #36.

Figure 7. Level of reflected light describing the thickness of the papillary dermis for the placebo emulsion, the verum containing 2% RP-SE and the emulsion containing the comparator. * p< 0.05; ** p< 0.01; *** p< 0.001 (Shapiro-Wilk test and for the product comparison mixed ANOVA model)).