Whitening and spot removing cosmetics for human efficacy testing

Whitening and spot removing cosmetics for human efficacy testing

The key link in the safety and efficacy evaluation system of cosmetics is to verify the improvement effect and safety of products on skin pigmentation through scientific and rigorous clinical trials. With the implementation of the "Regulations on the Supervision and Administration of Cosmetics" and supporting regulations, China has implemented strict registration management for special whitening and spot removing cosmetics, requiring enterprises to submit human efficacy testing reports issued by CMA qualified laboratories to ensure that product claims are consistent with actual effects.

Testing standards and regulatory basis

Whitening and spot removing cosmetics for human efficacy testingIt is necessary to strictly follow the requirements of the "Technical Specification for Safety of Cosmetics" (2022 edition) and the "Evaluation Specification for Cosmetic Efficacy Claims". The core testing standards include:

GB/T 35892-2018 "Evaluation Method for Whitening and Spot Removing Efficacy of Cosmetics": specifies the design principles, detection indicators, and result judgment standards for human trial experiments

Announcement No. 50 of 2021 by the National Medical Products Administration: It is explicitly required that whitening and spot removing products must undergo human efficacy evaluation, and the report must include subjective evaluation and objective instrument data

International Organization for Standardization ISO 24444:2019: Provides standardized methods for measuring skin color, including technical details such as instrument selection and control of testing conditions

It is worth noting that in 2023, the State Administration for Market Regulation released the "Catalogue of Non Nutritional Supplements with Health Functions that Allow Health Food Claims (2023 Edition)", which includes "helps improve melasma" in the standardized functional claims, further strengthening the compliance requirements for whitening and spot removing efficacy evaluation.

Experimental Design and Subject Management

Scientific and rational experimental design is the foundation for ensuring the accuracy of detection results. The standard experimental protocol adopts a randomized double-blind controlled design, mainly including:

Inclusion and exclusion criteria for subjects

Inclusion criteria: Women aged 18-65 with facial melasma or pigmentation, a melanin index (MI value) ≥ 200, and no use of whitening products in the past 3 months

Exclusion criteria: Pregnant or lactating women, those with pigmentary skin diseases (such as vitiligo), and those who have received laser whitening treatment in the past 6 months

Sample size requirement: Each group should have no less than 30 valid participants, taking into account a 20% dropout rate. The actual number of participants included was 36

Experimental grouping and dose design

Experimental group: Use the test sample twice a day (8am and 8pm) for 8 consecutive weeks

Control group: placebo without whitening ingredients, using the same method as the experimental group

Dose control: Follow the recommended dosage in the product manual (usually 1.0 ± 0.1g for single use on the face)

Ethical requirements

The experiment must pass ethical review, the subjects must sign an informed consent form, and the protocol must comply with the principles of the Helsinki Declaration. The testing institution needs to be equipped with a dedicated ethics committee to supervise the entire process of the experiment.

Core testing indicators and methods

The whitening and spot removing efficacy testing adopts a combination of subjective evaluation and objective instrument detection, with core indicators including:

Objective instrument testing

Melanin index (MI): measured using the Mexameter MX18 (Courage+Khazaka, Germany) in a fixed detection area (left cheekbone, right cheekbone, forehead), once a week, to calculate the rate of decrease in MI value

▶ Judgment criteria: The decrease rate of MI value in the experimental group is ≥ 10%, and the difference between the experimental group and the control group is statistically significant (P<0.05)

Spot area and intensity: Facial images were captured using Visiosan VC98 (Courage+Khazaka, Germany), and the color spot area (mm ²) and average grayscale value were analyzed using Image Pro Plus 6.0 software

▶ Key parameters: color spot area reduction ≥ 20%, intensity value reduction ≥ 15%

Transdermal Moisture Loss (TEWL): Evaluate skin barrier function using Tewameter TM300 to ensure whitening ingredients do not damage the skin

▶ Safety threshold: TEWL value change rate ≤ 15%

Subjective evaluation indicators

Clinical evaluation: Dermatologists use the Melasma Area and Severity Index (MASI) score, which includes depth of pigmentation (0-4 points), area (0-6 points), and homomorphic reaction (0-3 points)

▶ Effective criteria: MASI score reduced by ≥ 30%

Subject self-assessment: Use a 5-point Likert scale to evaluate the degree of improvement in pigmentation, skin brightness, and other indicators, and calculate the effective rate

▶ Questionnaire content: 8 core questions, including 'lightening of pigmentation' and 'overall brightening of the skin'

Data statistics and result judgment

The test data needs to be statistically analyzed using SPSS 26.0

Intra group comparison: Paired t-test is used to compare the changes in various indicators before and after use in the experimental group

Inter group comparison: Independent sample t-test was used to analyze the differences between the experimental group and the control group

Safety evaluation: Record the incidence of adverse events, including skin irritation reactions such as erythema and stinging

The comprehensive judgment criteria must simultaneously meet:

Instrument detection: The decrease rate of melanin index is ≥ 10%, and the reduction of color spot area is ≥ 20%

Clinical evaluation: MASI score reduced by ≥ 30%

Safety: The incidence of adverse events is less than 5%, and there are no serious adverse events

Technical capability requirements for testing institutions

The laboratory conducting whitening and spot removal efficacy testing on the human body must meet strict conditions:

Qualification requirements: Obtain CMA qualification certification, with testing capabilities including 'evaluation of whitening and spot removing effects of cosmetics'

Hardware facilities: equipped with a constant temperature and humidity laboratory (temperature 22 ± 1 ℃, humidity 50 ± 5%), with light intensity controlled within 500lux

Personnel configuration: At least 2 deputy directors or above dermatologists, with over 5 years of clinical evaluation experience in cosmetics

Quality control: Establish standard operating procedures (SOP), including instrument calibration (daily pre startup calibration), monitoring of testing environment, and data traceability system

Industry challenges and technological trends

The current whitening and spot removal testing faces two core challenges:

Sensitivity issue: The melanin particles on the skin of Asian populations are small and evenly distributed, and the instrument detection sensitivity needs to be improved (such as using reflectance spectroscopy)

Continuity of efficacy: Some products may experience pigment rebound after discontinuation, and the follow-up period needs to be extended to 4 weeks after discontinuation

Technological innovation direction:

No imaging technique: Optical Coherence Tomography (OCT) observation of changes in epidermal melanin distribution

Biomarkers: Detection of levels of melanin regulatory factors such as endothelin-1 (ET-1) and stem cell factor (SCF) in serum

3D skin model: replacing some animal experiments, such as using MelanoDerm ™ Prediction efficacy of recombinant melanocyte model

Typical Case Analysis

Test case of an international brand whitening essence:

Test sample: essence containing 3% transglutamic acid+2% nicotianamine

Experimental design: Randomized double-blind controlled trial, with 32 participants in the experimental group and 30 participants in the control group, using continuously for 8 weeks

Key Results:

▶ MI value decline rate: experimental group 18.7% vs control group 3.2% (P<0.01)

▶ MASI score: The experimental group decreased by 37.5%, while the control group decreased by 8.3%

▶ Safety: 2 cases of mild erythema with an incidence rate of 3.1%, the trial was not interrupted

Conclusion: This product has significant whitening and spot removing effects, and has good safety

Through systematic human efficacy testing, not only can it provide compliance basis for enterprise product registration, but it can also help consumers identify effective products. It is recommended that brand owners conduct efficacy screening tests during the product development phase to shorten the time to market. When consumers choose whitening and spot removing products, they can focus on whether the packaging is labeled with 'passed human efficacy testing' and CMA report number. If necessary, they can request the merchant to provide a key page of the testing report.