Ou Tingting,Liang Jiayi

R&D Center of Opal Cosmetics(Huizhou)Co.,Ltd.,China

Abstract To analyze and compare the cleaning power and moisturizing effect of different shower gels.Choose six types of shower gel,soap-based shower gel 1,soap-based shower gel 2,amino acid shower gel 1,amino acid shower gel 2,cream shower gel 1,cream shower gel 2.Control clinical studies,using the left and right arms for comparison.Apply special grease on the selected area on the forearm's flexion side,before and after applying the grease and after cleaning with shower gel,use Sebumeter SM815 for skin oil detection.Use shower gel on the other area on the forearm flexion side.Use Corneometer CM825 and Tewameter TM300 before and after cleaning.The moisture content of the stratum corneum and the amount of water loss through the epidermis were detected.Analyze the change rate of skin oil,stratum corneum moisture content,and transepidermal water loss,analyze and compare the cleansing and moisturizing effects of six shower gels of different systems.Results:After using the six shower gels to clean,the skin oil was significantly reduced while the moisture content of the stratum corneum and the amount of transepidermal water loss changed to different degrees.Layer moisture content and transepidermal water loss have varying degrees of influence.Conclusion:Amino acid shower gels and cream shower gels are stronger than soap-based shower gels in terms of moisturizing ability,and at the same time show similar effects to soap-based shower gels in terms of cleansing ability.

Key words body wash;cleansing;moisture content of cuticle;skin oil;transepidermal water loss

With the development of the daily chemical market,people’s requirements for bath products are no longer satisfied with the basic function of cleansing.For consumers,bath products have the functions of moisturizing and protecting the skin barrier,which is also the development of bath products towards more efficacy.A major trend[1,2].The correct cleaning of the skin is the basic requirement for maintaining the skin barrier function.The efficacy of cleansing cosmetics should be evaluated from two aspects,one is the ability to clean the skin,and the other is the ability to maintain normal skin barrier function[3,4].The use of cosmetics,sunscreen products,and color make-up also makes most people pay more attention to skin cleanliness.

Human skin is in direct contact with the outside world and is the first line of physical defense of the human immune system.On the one hand,it can prevent unfavorable factors such as external physics,chemistry,and microorganisms from entering the human body;on the other hand,it can avoid the loss of water and lipids in the human epidermis and dermis,and maintain the skin barrier function[5,6].The cleansing of the skin plays an important role in maintaining the function of the skin barrier.Correct cleaning can remove dirt on the surface of the skin,while protecting the skin barrier and ensuring a stable water content[1].

In this paper,by using special oil as the test carrier,using Sebumeter SM815,Corneometer CM825,and Tewameter TM300 to detect skin oil,stratum corneum moisture content,transepidermal water loss,and calculate the rate of change of skin oil,stratum corneum moisture content,and transepidermal water loss.Analyze and compare the cleansing power and moisturizing effect of shower gel.Corneometer CM825 is a classic instrument for detecting the moisture content of the stratum corneum of the skin.Ⅰt is often used to evaluate the moisturizing effect of cosmetics[7-9],and can detect the skin moisture content of patients with skin diseases to assess the condition and outcome of the disease[10,11].

1 Experimental part

1.1 Samples and instruments

Soap-based shower gel 1,soap-based shower gel 2,amino acid shower gel 1,amino acid shower gel 2,cream shower gel 1,cream shower gel 2 each;corneometer moisture content test probe Corneometer CM815,skin moisture loss test Probe Tewameter TM300,skin oil test probe Sebumeter SM815,Courage+Khazaka,50829 Koln,Germany.

1.2 Experimental method

1.2.1 Selection of test objects

Screening people aged 20～45 from a company,who have no serious systemic diseases,immune deficiency or autoimmune diseases,people without active allergic diseases,people who have no history of severe allergies to cosmetics,and have not used hormones in the past month Drugs and immunosuppressants,those who did not affect the determination of the test results due to scars,pigments,atrophy,port wine stains or other blemishes at the skin test site,those who did not participate in other clinical tests[12],use the test substance as required and The information is complete,and the volunteers signed an informed consent form before the test.

Temperature(21 ± 1)℃,humidity(40～60)%.

1.2.2 Initial value test

According to the principle of randomization,30 volunteers randomly selected the left arm flexion side or right arm flexion side skin as blank group A,and the other arm flexion side skin as experimental group B.

1.2.3 Efficacy test

Cleaning power test.Mark four 3×3 cm2 test areas at the corresponding positions on the flexion sides of the left and right forearms of the subject,with an interval of at least 1 to 1.5 cm between each area.Mark 3 test areas.The left and right corresponding positions are randomly set as blank areas and sample areas.Apply 0.018 g of special grease to the corresponding positions of the left and right arms.After testing the initial value,wash the blank area and the sample area with water and shower gel in circular motions for 20 times,and then rinse off.The blank areas A1,A2,A3 are rinsed with water,and the sample areas B1,B2,and B3 are washed with soap-based shower gel,amino acid shower gel,and cream shower gel,respectively.

Before each test,the subject sits still for at least 20 minutes in a constant temperature and humidity environment(21 ± 1)oC and humidity(40～60)%.The tester uses the skin oil test probe to test the subjects A1,A2,and A3.,B1,B2,B3 area location,record the skin oil value.The test of the same subject must be completed by the same tester using the same instrument,and the test probe should be cleaned between two measurements.

Moisture test.Mark four 3×3 cm2 test areas at the corresponding positions on the flexion side of the left and right forearms of the subject,with an interval of at least 1～1.5 cm between each area,mark 3 test areas,and set the left and right corresponding positions as blank areas and samples at random Area.After testing the initial value,the blank area and the sample area are washed with water and shower gel in circular motions for 20 times,and then rinse off.The blank areas C1,C2,C3 are washed with water,and the sample areas D1,D2,D3 are washed with soapbased shower gel,amino acid shower gel,and cream shower gel,respectively.

Before each test,the subject sits quietly for at least 20 minutes at a constant temperature and humidity environment temperature(21 ± 1)oC and humidity(40～60)%.The measuring staff uses the stratum corneum moisture content test probe and transepidermal water loss test.The probe test subjects C1,C2,C3,D1,D2,D3 area position,record the stratum corneum moisture content value,the value of transepidermal water loss.Each measurement area is measured twice and the average value is taken.The test of the same subject must be completed by the same tester using the same instrument,and the test probe should be cleaned between two measurements.

1.2.4 Statistical analysis

Statistical method:Use JMP professional statistical software to analyze,and objectively measure data(stratum corneum moisture content,skin oil,transepidermal water loss)for paired sample t-test.Compare the values before applying the sample,after applying the sample,and after cleaning,and perform a significant analysis.P<0.05 indicates that the difference is statistically significant.

2 Results and analysis

2.1 Human body efficacy evaluation test results

2.1.1 Data discrepancy test

Thirty volunteers who met the inclusion criteria were selected,and finally 30 people completed the trial.

The premise of the comparative validity of the test data is that there is no significant difference between the volunteer blank area and the sample area data before the sample is used.Therefore,the normal test is performed on the two sets of data.If the normal test(Sig.>0.05)is met(Table 1),the mean variance analysis and the Scheffe multiple comparison are performed,otherwise the nonparametric analysis of variance and the Wilicoxon rank sum test multiple comparison are performed.If thepvalue>0.05 in multiple comparisons,it means that there is no significant difference between the test points and they are comparable(Table 2).

Table 1.Normal test results of initial data

Table 2.Comparison of physiological parameter of test site before using the product

2.1.2 Statistics analysis

The test results of each index are shown in Table 3.The skin oil is compared after applying oil and cleansing,and the moisture content of the stratum corneum and transepidermal water loss are before and after the sample.

Table 3.Analysis of evaluation indexes before and after using the product

The data analysis is shown in Table 4.The skin oils of the six kinds of shower gels are significantly reduced,the water content of the stratum corneum of soap-based shower gels 1 and 2 is significantly reduced,and the transepidermal water loss is significantly increased.There was no significant difference in the moisture content of the stratum corneum and the amount of transepidermal water loss using amino acid shower gel 1,2,cream shower gel 1,2.

Table 4.Analysis of the change rate of evaluation index before and after cleaning

3 In Conclusion

This study shows that after using the amino acid shower gel and cream shower gel to clean the special oil,the water content of the stratum corneum and the water loss through the epidermis have no significant changes compared with those before the use of cosmetics,indicating that the cleaning did not cause adverse effects on the water content of the stratum corneum.There was no significant change in skin water loss.After cleaning with soap-based shower gel,the water content of the stratum corneum is significantly lower than before using cosmetics,the amount of transepidermal water loss is significantly higher than before using cosmetics,and the skin oil is significantly reduced,indicating that soap-based shower gel will reduce the skin while cleaning the skin.The moisture content of the stratum corneum increases the water loss of the skin.

Skin cleansing is the basic step of skin care.Thorough and gentle cleansing of the skin and maintaining the barrier function are of great significance.Using soap-based shower gel,amino acid shower gel,and cream shower gel have the same cleansing power on the skin.Amino acid shower gel and cream shower gel can maintain skin moisture content and no significant changes in skin water loss while cleaning.The three types of shower gels have different characteristics in terms of cleaning ability and moisturizing performance.Amino acid shower gels and cream shower gels are stronger than soap-based shower gels in terms of moisturizing ability,and at the same time appear to be the same as soap-based shower gels in terms of cleansing ability.