Moisturizing Efficacy Testing for Cosmetics Registration and Filing in China

Moisturizing efficacy testing provides the objective scientific evidence required to substantiate hydration claims during cosmetics registration and filing in China. Under the Cosmetics Supervision and Administration Regulation and its Efficacy Claim Evaluation Specification, brands must generate and publish verifiable efficacy data for moisturizing products before market entry. This article explains the regulatory framework, sample requirements, measured parameters, human trial methodologies, and practical considerations for completing moisturizing efficacy evaluation with accredited third-party laboratories.

Technical Overview

Moisturizing is one of the most frequently declared efficacy claims on cosmetic products marketed in China. Since the Cosmetics Supervision and Administration Regulation (CSAR) took effect on January 1, 2021, together with the NMPA Specification for Efficacy Claim Evaluation of Cosmetics effective May 1, 2021, every efficacy claim placed on a product label must be supported by adequate, verifiable scientific evidence.

For moisturizing claims, acceptable evidence routes include human efficacy trials, consumer use tests, laboratory instrumental methods, literature research, or research data analysis. In practice, human instrumental trials measuring stratum corneum hydration and transepidermal water loss (TEWL) are the industry-standard approach, because they generate objective, quantitative, and publication-ready data. An efficacy claim evaluation summary must be uploaded to the national cosmetics registration and filing information service platform and disclosed for public access.

Testing should be performed by accredited third-party laboratories or institutions with documented clinical testing capability, generally operating under ISO/IEC 17025 quality management systems and following Chinese national standards and NMPA technical requirements for efficacy evaluation.

Testing Samples

Creams, Lotions, and Emulsions

Leave-on emulsion systems are the most commonly tested category. These products are evaluated through both single-application and continuous-use protocols on defined test zones of the volar forearm or the face, covering immediate and sustained moisturizing performance.

Serums, Essences, Gels, and Oils

Low-viscosity water-based systems and anhydrous oil formulations require standardized application dosage per unit area to ensure reproducible dosing. These products are frequently tested with extended time-point schedules to demonstrate rapid absorption combined with lasting hydration.

Facial Masks and Sheet Masks

Occlusive products are applied for a defined contact period, typically 15 to 30 minutes, after which instrumental measurements are taken at successive intervals. Wash-off mask variants include a standardized rinsing step before measurement.

Body, Hand, and Foot Care Products

Products intended for larger body regions are tested on forearm or calf test sites using identical measurement principles, with dosages adjusted to reflect real-use conditions.

Sample submission requirements typically include the final marketed formulation from a representative production batch, usually 30 to 60 retail units or a minimum of 500 g or 500 mL per study, supplied in sealed original packaging within shelf life. The test sample formula must be identical to the formula submitted for filing and should be accompanied by the full ingredient list, product specification, and available safety data.

Testing Items

A standard moisturizing efficacy evaluation covers the following instrumental and observational endpoints:

• Stratum corneum hydration, measured as skin capacitance in arbitrary units
• Transepidermal water loss (TEWL), expressed in g/m²·h, reflecting skin barrier function
• Immediate moisturizing effect at 15 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, and up to 8 or 24 hours after a single application
• Long-lasting moisturizing effect after 1, 2, and 4 weeks of continuous twice-daily use
• Optional supporting parameters, including skin pH, skin elasticity, and epidermal desquamation assessment
• Dermatological tolerability monitoring and adverse reaction observation throughout the study

Testing Methods

Study Design and Subject Panel

Trials apply randomized, self-controlled, split-body designs with untreated or base-formula control zones. Healthy adult volunteers aged 18 to 60 are recruited according to defined inclusion and exclusion criteria; subjects with active skin disease, relevant allergies, or pregnancy are excluded. Enrollment exceeds the required number of valid completing subjects, commonly 30 or more, and all participants sign informed consent under an approved ethics review.

Environmental Control and Preconditioning

Measurements are conducted in a controlled climate room maintained at 20 to 22 °C and 40 to 60 percent relative humidity. Subjects acclimate for 20 to 30 minutes before each measurement, and the test area must remain free of cosmetics, washing, and intense physical activity prior to assessment.

Instrumentation

Stratum corneum hydration is quantified with a capacitance-based corneometer, while TEWL is measured with an open-chamber or closed-chamber evaporimeter. All instruments are calibrated before use, and three to five replicate readings per test zone are averaged to minimize measurement variability.

Application Protocol and Measurement Time Points

Fixed test zones, for example 3 x 3 cm sites on the volar forearm or defined cheek regions, are randomly assigned to product, control, or blank conditions. A standardized dose, commonly 2 mg/cm², is applied with a gloved finger or spatula. Single-application studies measure at baseline and successive intervals up to 8 or 24 hours; continuous-use studies apply the product twice daily for one to four weeks with instrumental assessments at weekly visits.

Data Analysis and Claim Substantiation Criteria

Hydration and TEWL values are compared against baseline and control zones using paired t-tests or analysis of variance, with statistical significance set at p less than 0.05. A moisturizing claim is substantiated when hydration increases significantly and meaningfully versus both baseline and control at the declared time points. Duration-specific claims, such as 24-hour or 48-hour moisture retention, require statistically significant data at the corresponding intervals. The final report documents the study protocol, subject demographics, raw data, statistical analysis, conclusions, and any adverse events.

Applications

Moisturizing efficacy test reports support multiple regulatory and commercial objectives across the product lifecycle:

• Filing and notification of general cosmetics in China, both domestic and imported, carrying moisturizing claims
• Preparation of the efficacy claim evaluation summary published on the national registration and filing platform
• Substantiation of label claims such as moisturizing, hydrating, long-lasting moisture, or 24-hour hydration
• Compliance documentation requested by domestic e-commerce platforms and live-commerce channels
• Research and development benchmarking, including formulation comparison and active-ingredient optimization
• Evidence packages for international registration and marketing claim support

FAQ

Is human efficacy testing mandatory for moisturizing claims?

Under the efficacy claim evaluation specification, moisturizing claims may be substantiated through literature research, research data analysis, or efficacy evaluation tests. Human instrumental trials remain the most widely accepted and defensible route, and any claim tied to a specific duration, percentage, or performance level must be supported by corresponding test data.

How many subjects are required?

Studies commonly require at least 30 valid subjects who complete the full protocol. Enrollment typically includes additional volunteers to compensate for dropouts, and larger panels provide stronger statistical power for marginally performing formulations.

How long does testing take?

Single-application studies generally require 2 to 4 weeks including recruitment, while continuous-use studies of one to four weeks require 5 to 8 weeks. Total turnaround from sample receipt to final report is typically 6 to 10 weeks.

Which instruments are used?

Capacitance-based corneometers measure stratum corneum hydration, and open-chamber or closed-chamber evaporimeters measure transepidermal water loss. Both techniques are non-invasive, repeatable, and suitable for longitudinal time-point measurements on the same test zones.

Can overseas test reports be used for Chinese filing?

Evidence generated abroad may be considered if it is scientifically sound and complete, but the published efficacy claim evaluation summary must be presented in Chinese. Conducting trials in accredited third-party laboratories in China under NMPA-aligned protocols typically reduces the risk of technical queries and filing delays.

What documentation is needed to initiate testing?

Required materials include finished product samples in final packaging, the complete formula with ingredient percentages, the product specification, available safety assessment information, the intended claim wording, and the desired protocol type and measurement time points.