Soothing cosmetics efficacy test (GB/T 38570-2020)

Soothing cosmetics efficacy test (GB/T 38570-2020)

Soothing cosmetics efficacy test (GB/T 38570-2020):The sensitive skin population is facing a dual dilemma: on the one hand, the annual growth rate of skincare products claiming to be 'soothing' and 'anti allergic' in the market has reached 25%; On the other hand, data from the National Medical Products Administration shows that in 2024, the proportion of cosmetics complaints caused by irritation reactions reached as high as 37%. Behind this contradiction lies a serious disconnect between efficacy claims and scientific verification. The release of GB/T 38570-2020 "Evaluation Methods for Soothing Efficacy of Cosmetics" has established a complete evaluation system for the industry, from objective indicators to subjective feelings. As a third-party testing agency that has passed the CMA/CNAS double certification, Zhongke Testing has completed more than 400 batches of product testing according to this standard. After 28 days of testing, a chamomile soothing facial mask has reduced the erythema index of subjects by 21.3%, and the level of IL-6 inflammatory factors by 34.7%, providing a solid data support for efficacy claims.

Standard Core Testing System and Technical Principles

GB/T 38570-2020 constructed a three-dimensional evaluation model of 'skin barrier+inflammatory factors+subjective perception'. At the objective indicator level, the standard clearly requires monitoring both the degree of skin redness and the level of inflammatory factors simultaneously. The erythema index (a * value) was measured using a Chromameter ® According to the CR400 test, the baseline facial value for healthy adults is usually between 8-12. After using high-quality soothing products for 28 days, it should decrease by ≥ 15%. A certain essence containing purslane extract reduced the cheek a * value of the subject from 10.7 to 8.4 during the test, reaching a significant improvement standard.

Inhibition of inflammatory factors is another core dimension of the standard. ELISA method is used to detect key indicators such as IL-6 and TNF - α, and the product is required to have an inhibition rate of ≥ 30% on LPS induced inflammatory factors. In actual detection, the face cream containing 0.5% bisabolol reduced the level of IL-6 from 186pg/mL to 112pg/mL, with an inhibition rate of 39.8%, which verified the mechanism of its relieving effect through regulating the inflammatory pathway.

The standard emphasizes the importance of lactate stinging test. By applying a 10% lactic acid solution to the forearm of the subjects and recording a pain score of 1-5 points (1 point for no sensation, 5 points for severe pain), the truly sensitive muscle population (score ≥ 3 points) was screened out. This strict inclusion criteria ensures the applicability of the experimental results to the target population.

Standardized testing process and quality control

The screening of subjects must meet strict inclusion criteria: healthy adults aged 18-60, with a clear history of facial sensitivity (such as intolerance to skincare products), and a lactate stinging score of ≥ 3 points. Each group has an effective sample size of ≥ 30 cases, ensuring statistical significance. A clinical study of a multinational brand showed that when the sample size increased from 20 to 30, the confidence level of the test results increased from 85% to 95%.

The experimental design adopts a double-blind control principle and is divided into a blank control group, a matrix control group, and three dose groups. Use 2mg/cm ² of the test product daily for 28 consecutive days, with key time points being 1 hour (immediate effect), 7 days (short-term effect), and 28 days (long-term effect) after use. Environmental control requirements include constant temperature (22 ± 1 ℃) and humidity (50 ± 5% RH). Participants are required to sit quietly for 30 minutes before testing to avoid interference factors such as temperature and emotions.

The reliability of data is guaranteed through three-level quality control: daily instrument calibration (accuracy error ≤ 2%), two person parallel experiments (data deviation<5%), and third-party blind review. A laboratory comparative experiment showed that the difference in erythema index measurements of the same subject by different operators was only 3.2%, far below the standard allowed threshold of 10%.

Technological Innovation and Practical Application Cases

Multidimensional validation technology breaks through the limitations of traditional single indicators and evaluates barrier repair effectiveness through TEWL values (transcutaneous water loss). During testing, a certain ceramide repair cream reduced the TEWL value from 23g/m ² h to 16g/m ² h, while increasing the moisture content of the stratum corneum by 27%, achieving a synergistic verification of 'soothing+repairing'.

In vitro 3D skin model accelerated efficacy screening using EpiSkin ™ Recombinant epidermal model, observe inflammatory cell infiltration through H&E staining. A certain plant extract reduced the inflammatory infiltration area by 42% in model experiments, and subsequent human trials confirmed that it can reduce skin sensitivity scores by 28.6%. This' in vitro in vivo 'dual validation mode shortens the product development cycle by 40%.

In practical applications, a certain brand optimized its formula based on the test results: the initial formula contained 0.3% menthol, which could bring a cool feeling, but caused 15% of the subjects to experience stinging reactions. By adjusting the compound formula to 0.1% menthol+0.2% urea extract, secondary testing showed that the irritation score decreased from 2.3 to 0.8, while maintaining a good soothing effect.

Advantages and Industry Value of Testing Services

The Zhongke Testing Soothing Effect Laboratory is equipped with a complete set of ISO 17025 certified equipment, including Vectra ® H1 3D imaging system (resolution 0.1mm), DUB ® Ultrasonic skin tomography scanner (22MHz high-frequency probe) can synchronously obtain deep indicators such as epidermal thickness and dermal density. The repair patch of a certain medical beauty brand has been confirmed through ultrasound testing to increase the thickness of the dermal mesh layer by 11%, providing direct evidence for the claim of 'barrier repair'.

Compliance support covers the whole process: from formula pre evaluation (avoiding essence/alcohol and other irritants), clinical trial design (ethical review) to report issuance (in line with the Evaluation Specification for Efficacy Claims of Cosmetics). In 2024, assisted a domestic brand in completing the testing of the 'Centella asiatica glycoside+panthenol' composite formula. The report showed that after 28 days, the improvement rate of skin sensitivity reached 67%, successfully entering the sensitive skin category on Tmall

With the deepening implementation of the Regulations on the Supervision and Administration of Cosmetics, GB/T 38570-2020 has become a 'passport' for the entry of soothing products into the market. Enterprises should attach importance to early detection intervention and establish consumer trust through scientific data. According to data from Zhongke Testing, the verified soothing products have increased consumer repurchase rates by 2.3 times and reduced complaint rates by 65%, truly achieving a win-win situation between commercial value and consumer interests.