Genipin-based skin metabolism visual evaluation agent and application thereof

Abstract

The invention relates to a genipin-based skin metabolism visual evaluation agent and application thereof, and belongs to the technical field of cosmetics. The invention provides a skin metabolism visualization evaluation agent which comprises the following components in parts by mass: 1-2 parts of genipin, 0.4-0.7 part of a coloring agent and 0.1-0.5 part of a thickening agent, and the pH value of the skin metabolism visualization evaluation agent is 6.0-6.5. The genipin, the coloring agent and the thickening agent are combined into the skin metabolism visual evaluation agent, so that the skin can be effectively dyed, the safety is relatively good, and the metabolism condition of the skin can be more intuitively and accurately evaluated. Meanwhile, the skin metabolism visualization evaluation agent is high in adhesive force on the skin, better in stability and material uniformity and more uniform in dyeing effect, can be used in people with deep skin color and light skin color, and is not limited by a test area.

Description

Technical Field

[0001] The present invention relates to the technical field of cosmetics, and particularly relates to a genipin-based skin metabolism visualization evaluation agent and its application. Background Art

[0002] At present, the evaluation of the skin stratum corneum metabolism rate and the characterization of the exfoliating efficacy of cosmetics mainly rely on subjective evaluation and indirect measurement methods, and these methods have certain limitations:

[0003] The tape stripping technique has problems such as inconsistent stratum corneum stripping amount caused by operator differences and inconsistent experimental conditions, and has disadvantages such as large inter-individual variation and poor repeatability;

[0004] Dihydroxyacetone (DHA) stain has potential carcinogenic risks to the skin, is inconvenient to operate, requires patch applicator application for 24 hours, the staining effect is close to that of the deeper skin color of the human body, and the evaluation effect for people with deep skin color is not good.

[0005] Therefore, it has important practical significance to develop an intuitive, accurate and safe skin stratum corneum metabolism visualization evaluation agent for the evaluation of the skin stratum corneum metabolism rate and the characterization of the exfoliating efficacy of cosmetics and cosmetic raw materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an intuitive, accurate, safe, genipin-based skin metabolism visualization evaluation agent, and provide its application in evaluating the skin stratum corneum metabolism rate and the exfoliating efficacy of cosmetics and cosmetic raw materials.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, the present invention provides a skin metabolism visualization evaluation agent, comprising the following components in parts by mass: 1-2 parts of genipin, 0.4-0.7 parts of coloring agent, 0.1-0.5 parts of thickening agent, and the pH value of the skin metabolism visualization evaluation agent is 6.0-6.5.

[0009] Genipin is a natural compound extracted from plants, commonly used in food, medicine and cosmetics, has good dyeing performance and biocompatibility, and has low harm to the skin. Since genipin is colorless when dissolved in water, a bright coloring agent similar to the post-staining effect is required to be used in combination with genipin. The addition of the thickening agent can make the skin metabolism visualization evaluation agent prepared into a gel dosage form, which is more convenient for storage and use. The present invention combines genipin, coloring agent and thickening agent into a skin metabolism visualization evaluation agent, which can effectively stain the skin, has good safety, and can more intuitively and accurately evaluate the metabolism of the skin.

[0010] The present invention has been experimentally verified that the concentration range of genipin is closely related to its staining effect on the skin stratum corneum. The higher the concentration of genipin, the deeper the staining effect, the longer the metabolism time required, and the longer the time required to reach the strongest staining effect. Exceeding the recommended concentration of 2 wt% may require more than 24 hours to reach the strongest staining effect. At the same time, too deep a staining effect will cause the measurement data to change insignificantly, resulting in certain errors.

[0011] As a preferred embodiment of the skin metabolism visualization evaluation agent described in the present invention, the purity of genipin is 95-99%.

[0012] As a preferred embodiment of the skin metabolism visualization evaluation agent described in the present invention, the colorant includes at least one of gardenia blue, betanin, and monascus red. The present invention selects food colorants, which can effectively reduce the risk of skin allergies, dryness and other phenomena caused by using traditional colorants such as DHA and gentian violet, and has higher safety.

[0013] As a preferred embodiment of the skin metabolism visualization evaluation agent described in the present invention, the thickener includes at least one of xanthan gum, guar gum, and carrageenan. The skin metabolism visualization evaluation agent of the present invention is added with a thickener to be prepared into a gel dosage form, which brings better adhesion to the skin metabolism visualization evaluation agent, can stay on the skin surface for a long time, and thus provides a more lasting and uniform staining effect. Xanthan gum is a natural high molecular polysaccharide produced by bacterial fermentation, which is considered a safe biopolysaccharide, non-toxic and non-growth inhibitory to rats and dogs, has no irritation to eyes and skin, and has excellent suspension ability and stabilizing effect. It is not very sensitive to pH and can be used directly after dispersion.

[0014] As a preferred embodiment of the skin metabolism visualization evaluation agent described in the present invention, the skin metabolism visualization evaluation agent further includes 12-20 parts by mass of a cosolvent. The solubility of genipin in water is relatively low, about 1% at room temperature (25°C). As the temperature increases, the solubility increases. It can be seen that adding a cosolvent to the skin metabolism visualization evaluation agent of the present invention can promote the dissolution of genipin and the colorant, and at the same time improve the drying speed of the skin metabolism visualization evaluation agent on the skin, so that the skin metabolism visualization evaluation agent can better color the skin.

[0015] As a preferred embodiment of the skin metabolism visualization evaluation agent of the present invention, the co-solvent includes ethanol and propylene glycol, and the mass ratio of ethanol to propylene glycol in the co-solvent is ethanol:propylene glycol = (2 - 7.5):1. The present invention preferably uses alcohols with relatively strong volatility as co-solvents because genipin is soluble in organic solvents such as ethanol and propylene glycol. Ethanol and propylene glycol have the functions of co-solubilization, antibacterial and antiseptic at the same time. In addition, propylene glycol also has a certain thickening and stabilizing effect. The compound use can play a synergistic and complementary role between the two, which can not only reduce the amount of raw materials but also expand the application range.

[0016] As a preferred embodiment of the skin metabolism visualization evaluation agent of the present invention, the co-solvent includes ethanol and propylene glycol, and the mass ratio of ethanol to propylene glycol in the co-solvent is ethanol:propylene glycol = 5:1.

[0017] As a preferred embodiment of the skin metabolism visualization evaluation agent of the present invention, the skin metabolism visualization evaluation agent further includes 0.01 - 0.05 parts by mass of a preservative and 75 - 90 parts by mass of water. In order to extend the shelf life of the skin metabolism visualization evaluation agent of the present invention, the present invention preferably adds the preservative to the skin metabolism visualization evaluation agent.

[0018] As a preferred embodiment of the skin metabolism visualization evaluation agent of the present invention, the skin metabolism visualization evaluation agent further includes 0.01 - 0.05 parts by mass of a preservative and 75 - 90 parts by mass of water.

[0019] As a preferred embodiment of the skin metabolism visualization evaluation agent of the present invention, the preservative is phenoxyethanol.

[0020] In the second aspect, the present invention provides a preparation method of the above skin metabolism visualization evaluation agent, including the following steps:

[0021] (1) Mix ethanol in the co-solvent with genipin, add propylene glycol in the co-solvent, and stir evenly to obtain phase A;

[0022] (2) Pre-disperse the thickener with a small amount of water, then add an appropriate amount of water, and dissolve the thickener by heating in a water bath to obtain phase B;

[0023] (3) Mix phase A obtained in step (1) with phase B obtained in step (2), homogenize at 5000 - 6000 rpm for 5 - 6 min, add a colorant, a preservative and a pH regulator, and adjust the pH to 6.0 - 6.5 to obtain the skin metabolism visualization evaluation agent.

[0024] In the third aspect, the present invention provides the application of the above skin metabolism visualization evaluation agent in the evaluation method of the skin stratum corneum metabolism rate.

[0025] In a fourth aspect, the present invention provides a method for evaluating the exfoliating efficacy of cosmetics and / or cosmetic raw materials using the aforementioned skin metabolism visualization evaluator.

[0026] In a fifth aspect, the present invention provides a method for evaluating the metabolic rate of the skin stratum corneum, comprising the following steps:

[0027] A1. Select an area on the subject's body with similar color and pigmentation as the test area. Before dyeing, the subject should sit quietly in a constant temperature and humidity environment for at least 20 minutes to ensure skin stability.

[0028] A2. Apply the above-mentioned skin metabolism visualization evaluation agent to the test area described in step A1, let it stand for 20-60 minutes, and then rinse with water. The area where the skin metabolism visualization evaluation agent was applied will appear blue-green.

[0029] A3. Use a Visia imager to take pictures and measure the average b* value of the test area, and calculate the stratum corneum metabolic rate according to formula (1). Formula (1) is as follows:

[0030]

[0031] In formula (1), γ x ——Indicates the metabolic rate of the stratum corneum on day x after dyeing and modeling;

[0032] Δb * ——Indicates the difference between the xth day and the 0th day after staining modeling * value difference;

[0033] Δt x ——Indicates the difference between day x and day 0 after dyeing and modeling;

[0034] b0 * ——Indicates the 0th day after staining modeling b * value;

[0035] b x * ——Indicates the xth day after dyeing and modeling * value;

[0036] t x ——Indicates the number of days x after dyeing and modeling;

[0037] t0——indicates the number of days after staining and modeling.

[0038] In the present invention, the b* value refers to the b* value among the L*, a*, and b* values in the CIELAB color space.

[0039] As a preferred embodiment of the evaluation method of the present invention, in step A1, the sitting time is 20 - 30 min. Sitting still is to stabilize the skin condition, and generally 20 min or more is required to ensure the stability of the skin condition.

[0040] In a sixth aspect, a method for evaluating the exfoliating effect of a cosmetic and / or a cosmetic raw material includes the following steps:

[0041] B1. Select areas on the subject's body with similar skin color and pigmentation degree as the test areas. The subject sits still in a thermostatic and humid environment for at least 20 min before staining to ensure the stability of the skin condition;

[0042] B2. Apply the above-mentioned skin metabolism visualization evaluation agent to the test areas described in step B2, leave it for 20 - 30 min, and then wash it with clear water. At this time, the areas where the skin metabolism visualization evaluation agent is applied show blue or red;

[0043] B3. Use the cosmetic or cosmetic raw material to be tested in the test areas, and use a visia imager to take pictures and measure the average b* value of the test areas. Calculate the change rate of the b* value according to formula (2). If there is a significant difference between the change rate of the b* value of the test group and that of the control group at any follow-up point, it is considered that the cosmetic or cosmetic raw material has an exfoliating effect. Formula (2) is as follows:

[0044]

[0045] In formula (2), b base * —— represents the b * value before staining and model establishment;

[0046] b0 * —— represents the b * value on the 0th day after staining and model establishment;

[0047] b x * —— represents the b * value on the xth day after staining and model establishment.

[0048] As a preferred embodiment of the method of the present invention, in step B1, the sitting time is 20 - 30 min. Sitting still is to stabilize the skin condition, and generally 20 min or more is required to ensure the stability of the skin condition.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] (1) The present invention combines genipin, a colorant, and a thickener into a skin metabolism visualization evaluation agent, which can effectively stain the skin, has good safety, and can more intuitively and accurately evaluate the metabolism of the skin. At the same time, the skin metabolism visualization evaluation agent of the present invention has strong adhesion on the skin, better stability and material uniformity, more uniform staining effect, can be used in people with dark skin and light skin, and is not restricted by the test area.

[0051] (2) The skin metabolism visualization evaluation agent of the present invention is easy to use and has uniform staining. There is no need to apply adhesive tapes or patchers. The best staining effect can be achieved after leaving it for 24 hours, which greatly shortens the operation time and process, reduces the risk of adverse reactions caused by long-term application of adhesive tapes and patchers. At the same time, detecting the b* value of the skin only requires the use of visia imaging technology, without the need to purchase specific color probes, reducing the phenomenon of data deviation caused by uneven staining. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It shows the skin pigment metabolism of groups N1, N3 - N5 in Effect Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0054] Other materials, reagents, etc. used in the examples, comparative examples and effect examples can be obtained from commercial channels without special instructions.

[0055] In the following examples, comparative examples and effect examples, the recruited volunteers need to meet the following conditions:

[0056] 1. Aged 18 - 60 years old, gender is not limited, skin type Ⅰ - Ⅳ;

[0057] 2. The test site has not participated in other clinical trials within the past month;

[0058] 3. The test site has not participated in other exfoliating efficacy tests within the past month;

[0059] 4. Have not taken oral medications such as isotretinoin that promote stratum corneum metabolism within the past month;

[0060] 5. Have not taken a bath or used any skin care products within 24 hours before the experiment;

[0061] 6. Clean the skin before the experiment.

[0062] Examples 1 - 3 and Comparative Examples 1 - 3

[0063] Examples 1-3 and Comparative Examples 1-3 respectively provide a skin metabolism visualization evaluation agent and a preparation method thereof. The components and dosages of the skin metabolism visualization evaluation agent are shown in Table 1. The preparation method includes the following steps:

[0064] (1) Mix the ethanol in the co-solvent with genipin, add the propylene glycol in the co-solvent, and stir evenly to obtain Phase A;

[0065] (2) Pre-disperse the thickener with a small amount of water, then add an appropriate amount of water, and heat it in a water bath to dissolve the thickener to obtain Phase B;

[0066] (3) Mix Phase A obtained in step (1) with Phase B obtained in step (2), homogenize at 5000 - 6000 rpm for 5 - 6 min, add a colorant and a preservative, and adjust the pH value to 6.0 - 6.5 with a pH regulator to obtain the skin metabolism visualization evaluation agent.

[0067] Table 1 Components and dosages (parts by mass) of different skin metabolism visualization evaluation agents

[0068]

[0069] Example 4

[0070] Example 4 provides a method for evaluating the metabolism rate of the skin stratum corneum, including the following steps:

[0071] A1. Select areas on the subject's body with similar skin color and pigmentation degree as the test areas. The subject sits quietly in a constant temperature and humidity environment for 20 - 30 min before staining to ensure stable skin condition;

[0072] A2. Take the above-mentioned skin metabolism visualization evaluation agent and apply it to the test areas described in step A1. After standing for 30 min, wash it with clean water. At this time, the areas coated with the skin metabolism visualization evaluation agent show blue - green;

[0073] A3. Use a visia imager to take pictures and measure the average b* value of the test areas, and calculate the stratum corneum metabolism rate according to formula (1). Formula (1) is as follows:

[0074]

[0075] In formula (1), γ x —— represents the stratum corneum metabolism rate on the x - th day after staining and model establishment;

[0076] Δb * —— represents the difference in b value between the x - th day and the 0 - th day after staining and model establishment; * value difference;

[0077] Δt x——Indicates the difference between day x and day 0 after dyeing and modeling;

[0078] b0 * ——Indicates the 0th day after staining modeling b * value;

[0079] b x * ——Indicates the xth day after dyeing and modeling * value;

[0080] t x ——Indicates the number of days x after dyeing and modeling;

[0081] t0——indicates the number of days after staining and modeling.

[0082] In this embodiment, the b* value refers to the b* value among the L*, a*, and b* values in the CIELAB color space. When the b* value is negative, it indicates that the skin in the area appears blue, and when the b* value is positive, it indicates that the skin in the area appears yellow.

[0083] Example 5

[0084] Example 5 provides a method for evaluating the metabolic rate of the skin stratum corneum. The steps are similar to those of Example 4, except that in step A2, the skin metabolism visualization evaluation agent is applied and then allowed to stand for 60 minutes, and the remaining steps and parameter conditions remain unchanged.

[0085] Example 6

[0086] Example 6 provides a method for evaluating the exfoliating efficacy of cosmetics and / or cosmetic raw materials, comprising the following steps:

[0087] B1. Select an area on the subject's body with similar color and pigmentation as the test area. Before dyeing, the subject should sit quietly in a constant temperature and humidity environment for 20-30 minutes to ensure the skin condition is stable.

[0088] B2. Apply the above-mentioned skin metabolism visualization evaluation agent to the test area described in step B2, let it stand for 30 minutes, and then rinse with water. The area where the skin metabolism visualization evaluation agent was applied will appear blue-green.

[0089] B3. Use a Visia imager to take photos and measure the average b* value of the test area. Calculate the b* value change rate according to formula (2). Apply 1% salicylic acid solution to the test area daily starting from the first day after dyeing. If the b* value change rate of the test group is significantly different from that of the control group at any return visit point, the cosmetic or cosmetic raw material is considered to have exfoliating effect. Formula (2) is as follows:

[0090]

[0091] In formula (2), b base * —— represents the b value before dyeing and modeling; * value;

[0092] b0 * —— represents the b value on the 0th day after dyeing and modeling; * value;

[0093] b x * —— represents the b value on the xth day after dyeing and modeling; * value.

[0094] In this embodiment, the b* value refers to the b* value among the L*, a*, and b* values in the CIELAB color space. When the b* value is negative, it indicates that the skin in this area appears blue; when the b* value is positive, it indicates that the skin in this area appears yellow.

[0095] Example 7

[0096] Example 7 provides a method for evaluating the exfoliating efficacy of cosmetics and / or cosmetic raw materials. The steps are similar to those in Example 6, except that in step B2, after applying the skin metabolism visualization evaluation agent, it is left standing for 60 min, and the remaining steps and parameter conditions remain unchanged.

[0097] Comparative Example 4

[0098] Comparative Example 4 provides a method for testing the exfoliating efficacy of cosmetics, including the following steps:

[0099] C1. According to the second method of the group standard "TGDCDC 032-2023 Test Method for Exfoliating Efficacy of Cosmetics", prepare a 10 wt% aqueous solution of dihydroxyacetone (DHA);

[0100] C2. Conduct a skin baseline value test, and the obtained test value is (BASE);

[0101] C3. Select a patch tester with a diameter of 25 mm. Immerse the filter paper in the patch tester in the 10 wt% aqueous solution of DHA for 10 min, put the soaked filter paper into the patch tester, and the staff stick the patch tester to the test area;

[0102] C4. After 24 hours, remove the patch. The test area should not be washed with water. After removing the patch tester for 4 hours, when the skin in the test area is stably dyed, test the b* value of this area. The calculation formula for the change rate of the b* value is the same as formula (2) mentioned in Example 6. Starting from the 1st day after dyeing, apply a 1% salicylic acid solution to the test area every day.

[0103] Effect Example 1

[0104] The skin metabolism visualization evaluation agents obtained in Examples 1-3 were respectively evaluated according to an evaluation method for the metabolism rate of the skin stratum corneum in Example 6, and the obtained test group data were denoted as N1, N2, and N3; the skin metabolism visualization evaluation agent obtained in Example 1 was evaluated according to an evaluation method for the metabolism rate of the skin stratum corneum in Example 7, and the obtained test group data were denoted as N4; it was evaluated according to a test method for the exfoliating efficacy of cosmetics in Comparative Example 4, and the obtained test group data were denoted as N5. The above N1-N5 group data are shown in Tables 2-3 and Figure 1 。

[0105] Table 2 b* values of exfoliating efficacy obtained by different methods

[0106]

[0107] Table 3 Change rate of b* value of exfoliating efficacy obtained by different methods

[0108]

[0109] As Figure 1 shown, BASE is the skin base b * value before staining, and the b * value on the 0th day (D0) was measured 24 h to 32 h after staining. When the b * value is larger, it indicates that the skin color is more yellowish; when the b * value is smaller, it indicates that the skin color is more bluish. The skin of groups N1, N3-N4 was initially blue and the color distribution was uniform. As time passed, the blue color began to be metabolized and gradually showed blue-green. At the 14th day (D14), the tested areas of N1, N3-N4 still showed blue, while at this time, it was impossible to observe with the naked eye whether the tested area of N5 was still colored. This shows that the adhesion and stability of the traditional staining method are poor. After skin metabolism, the stained area of the traditional method is close to the skin color with the naked eye, making it difficult to evaluate the skin keratin metabolism well. However, the skin metabolism visualization evaluation agent and staining method of the present application have a color with a large difference from the skin and better adhesion and stability. As shown in Tables 2-3, compared with N1, N2 reached the best effect on the 1st day after staining and had a longer staining time; compared with N5, the b * value of N4 changed more greatly.

[0110] Effect Example 2

[0111] The skin metabolism visualization evaluation agents obtained in Comparative Examples 1-3 were respectively evaluated according to an evaluation method for the metabolism rate of the skin stratum corneum in Example 6, and the obtained test group data were denoted as D1, D2, and D3. The obtained test group data are shown in Tables 4-5.

[0112] Table 4 b* values of exfoliating efficacy obtained by different methods

[0113]

[0114] Table 5 Rate of change of b* value of exfoliating efficacy obtained by different methods

[0115]

[0116] As shown in Tables 4 - 5, by comparing the data of Group N1 with that of Group D3, it can be obtained that replacing Gardenia blue with Gentian violet will result in poor dyeing effect of the skin metabolism visualization agent, and the color has been completely metabolized at the 14th day after dyeing, making it impossible to judge the long - term exfoliating effect of the product; by comparing the data of Group N1 with that of Groups D1 and D2, when the dosages of genipin and the colorant are not within the ranges of 0.5 - 1.5 parts by mass and 0.4 - 0.7 parts by mass, the skin color of the test area has been completely metabolized at the 7th day (Group D1), or the skin color of the test area is too deep. Even after using the exfoliating product, there will still be a relatively deep color at the 14th day after dyeing, causing a certain error and seriously affecting the evaluation of the exfoliating efficacy of the product, and making it impossible to accurately judge the exfoliating effect of the product. Therefore, considering comprehensively, when the mass fraction of genipin in the skin metabolism visualization agent of the present invention is 0.5 - 2.5 and the mass fraction of the colorant is 0.4 - 0.7, the dyeing effect of the evaluation agent is the best.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A genipin-based visual evaluation agent for skin metabolism, characterized in that, Comprising the following components in parts by mass: genipin 0.5 - 2.5 parts, colorant 0.4 - 0.7 parts, thickener 0.1 - 0.5 parts, and the skin metabolism visualization evaluation agent has a pH value of 6.0 - 6.

5.

2. The skin metabolism visualization evaluation agent according to claim 1, wherein The colorant includes at least one of gardenia blue, beet red, and monascus red.

3. The skin metabolism visualization evaluation agent according to claim 1, characterized in that, The thickener includes at least one of xanthan gum, guar gum, and carrageenan.

4. The skin metabolism visualization evaluation agent according to claim 1, characterized in that, The skin metabolism visualization evaluation agent further includes 12 - 20 parts by mass of cosolvent.

5. The skin metabolism visualization evaluation agent according to claim 4, characterized in that, The cosolvent includes ethanol and propylene glycol, and the mass ratio of ethanol to propylene glycol in the cosolvent is ethanol:propylene glycol = (2 - 7.5):

1.

6. The skin metabolism visualization evaluation agent according to claim 1 or 4, characterized in that, The skin metabolism visualization evaluation agent further includes 0.01 - 0.05 parts by mass of preservative and 75 - 90 parts by mass of water.

7. The skin metabolism visualization evaluation agent according to any one of claims 1 - 6 is applied in a method for evaluating the skin stratum corneum metabolism rate.

8. The skin metabolism visualization evaluation agent according to any one of claims 1 - 6 is applied in a method for evaluating the exfoliating efficacy of cosmetics and / or cosmetic raw materials.

9. A method for evaluating the metabolic rate of the skin stratum corneum, characterized in that, Comprising the following steps: A1. Select areas on the subject's body with similar skin color and pigmentation degree as the test areas. The subject sits still in a constant temperature and humidity environment for at least 20 minutes before staining to ensure stable skin condition. A2. Take the skin metabolism visualization evaluation agent according to any one of claims 1 - 6 and apply it to the test areas described in step A1. After standing for 20 - 60 minutes, wash it with clear water. At this time, the areas smeared with the skin metabolism visualization evaluation agent show blue - green. A3. Use a visia imager to take pictures and measure the average b* value of the test areas, and calculate the stratum corneum metabolism rate according to formula (1). Formula (1) is as follows: In formula (1), γ x —— represents the cutin metabolism rate on the x-th day after dyeing and modeling; Δb * —— represents the difference in the b value between the x-th day and the 0-th day after dyeing and modeling; * Value difference; Δt x —— represents the number of days between the x-th day and the 0-th day after dyeing and modeling; b0 * —— Represents the b value on the 0th day after dyeing and modeling * value; b x * —— represents the b value on the x-th day after dyeing and modeling * value; t x —— represents the number of days on the x-th day after dyeing and modeling; t0 —— represents the number of days on the 0th day after staining and model establishment.

10. A method for evaluating the exfoliating efficacy of a cosmetic and / or a cosmetic raw material, characterized in that, Comprising the following steps: B1. Select areas on the subject's body with similar skin color and pigmentation degree as the test areas. The subject sits still in a constant temperature and humidity environment for at least 20 minutes before staining to ensure stable skin condition. B2. Take the skin metabolism visualization evaluation agent according to any one of claims 1 - 6 and apply it to the test areas described in step B2. After standing for 20 - 30 minutes, wash it with clear water. At this time, the areas smeared with the skin metabolism visualization evaluation agent show blue or red. B3. Use the test cosmetics or test cosmetic raw materials in the test areas, and use a visia imager to take pictures and measure the average b* value of the test areas. Calculate the b* value change rate according to formula (2). If the b* value change rate of the test group is significantly different from that of the control group at any follow - up point, it is considered that the cosmetics or cosmetic raw materials have exfoliating efficacy. Formula (2) is as follows: In formula (2), b base * —— represents the b * value before dyeing and modeling; b0 * —— represents the b value on the 0th day after dyeing and modeling * value; b x * —— represents the value of b on the x-th day after dyeing and modeling * value.

Images