On July 31, 2025, the National Institutes for Food and Drug Control (NIFDC) released six Technical Guidelines, including the Technical Guidelines for the Study of Hair Dye Cosmetics (Trial) (Draft for Comments), to solicit public opinions. The following is a detailed interpretation of the Technical Guidelines for the Study of Hair Dye Cosmetics (Trial) (Draft for Comments) and the Technical Guidelines for the Study of Quality Control Standards for Hair Dye Cosmetics (Trial). This aims to assist enterprises in keeping up with regulatory and policy changes in a timely manner, ensuring smooth adaptation to regulatory developments.
I. Technical Guidelines for the Study of Hair Dye Cosmetics (Trial) (Draft for Comments)
1. Scope of Application
Hair dye cosmetics refer to cosmetic products intended to change the color of hair, where the original hair color cannot be restored immediately after rinsing following application.
2. General Principles
The research focuses on technical aspects such as safety, quality, efficacy, and labeling claims.
3. Main Content
(1) Mechanism of Action Study
Hair dye cosmetics are categorized into oxidative and non-oxidative types:
- Oxidative hair dye cosmetics typically consist of two components—dye precursors and oxidizing agents (e.g., hydrogen peroxide)—and involve redox reactions.
- Non-oxidative hair dye cosmetics are usually single-component products that do not involve oxidation reactions.
Hair dye products used for bleaching generally contain only oxidizing agents and are classified as oxidative hair dye cosmetics. Non-oxidative hair dye cosmetics primarily achieve hair coloring through mechanisms such as dye penetration and adsorption.
For products that differ from the above categories (e.g., single-component oxidative types), the mechanism of action must be thoroughly studied, with a clear explanation of the hair dyeing mechanism and supporting scientific evidence.
(2) Study on Quality Controllability
Raw materials:
- Use hair dyes permitted in the Safety and Technical Standards for Cosmetics (STSC), and pay attention to the specific requirements for different hair dyes. For example:
- Quality specification requirements: For the hair dye N,N-Bis(2-hydroxyethyl)-p-phenylenediamine sulfate, the “Other restrictions and requirements” are: “Do not use in nitrosating systems; maximum nitrosamine content: 50 mg/kg; store in containers free of nitrites.”
- Other restrictions and requirements: When GALLA RHOIS extract is used as a hair dye in hair dye cosmetics, it must be used in combination with ferrous sulfate.
- Usage limit requirements: The maximum allowed concentration of p-phenylenediamine in oxidative hair dye products is 2.0%.
- Oxidizing agents are generally hydrogen peroxide, sodium perborate, etc. Their use must comply with the requirements of the STSC. For example: When hydrogen peroxide and other compounds or mixtures that release hydrogen peroxide are used in hair products, the maximum allowed concentration is 12% (calculated as present or released H2O₂).
- Use of new ingredients during the monitoring period requires authorization and must comply with the requirements specified in the registration or notification information of the new ingredient.
Formulation:
- The formulation includes the base formula and functional ingredients. Pay attention to the compatibility between the base formula and functional ingredients. For example, since hair dyes are easily oxidized, antioxidants (such as ascorbic acid) are generally added.
- Oxidative hair dye cosmetics are usually in two-component systems. Dye formula: contains hair dyes, antioxidants/reducing agents, chelating agents, pH adjusters, etc. Oxidant formula: contains strong oxidizing agents, chelating agents, pH adjusters, etc.
- Colorants prohibited for use in hair dye products according to the Technical Specifications must not be used. If permitted colorants are used, it must be clearly indicated whether they participate in the dyeing process; for oxidative hair dye products, the stability of organic colorants under oxidative conditions should be thoroughly studied.
Manufacturing Process and Quality Control:
- Manufacturing process: Highlight key steps, such as the emulsification process for cream, lotion, and similar formulations. Special attention should be paid to the processes and parameters related to hair dyes, such as dosing accuracy and temperature control.
- Quality control: In principle, the physicochemical and microbiological items set for quality control should not be fewer than those required in the Testing Specifications.
(3) Safety Assessment
Product registration testing: The testing items should be no fewer than those required in the Testing Specifications. Microbiological testing is exempted for oxidative hair dye cosmetics.
Safety assessment:
- Based on all ingredients in the declared formulation and known risk substances, while also considering relevant information such as product usage method, application site, and exposure level.
- Organic colorants may participate in redox reactions; therefore, studies should be conducted to determine whether their chemical structures and concentrations change under oxidative conditions.
- For products that require the combination of two or more components for use, the ingredient content after mixing should be assessed according to the usage method. If multiple mixing ratios exist, the actual usage amount of each ingredient under each ratio should be evaluated. Additionally, literature or experimental data should be used to analyze potential chemical and/or biological interactions between ingredients that may pose safety risks.
(4) Efficacy Evaluation Study
For hair dye products that differ from oxidative (two-component) and non-oxidative (single-component) types, the product efficacy should be thoroughly evaluated based on its hair dyeing mechanism.
(5) Label Claims
Classification code: Must include at least “hair dye”; the site of action must be limited to hair only. The target user group must not include infants or children.
Product name: Misleading product names such as “plant-based hair dye” are not allowed. In principle, product names that may mislead consumers into thinking the hair dye is a general cosmetic—such as “shampoo” or “conditioner”—should not be used.
Label claims:
- The “net content” must clearly indicate the specific net content of each component. The instructions for use must specify the mixing ratio of each component when used.
- For claims involving skin allergy testing, the test duration should be no less than 48 hours.
- Misleading claims such as “plant-based hair dye,” “wash and dye,” “perm and dye,” or “one-wash black” are prohibited. Oxidative hair dye products should not claim to be “mild” or “safe.”
II. Technical Guidelines for the Study of Quality Control Standards for Hair Dye Cosmetics (Trial)
The implementation of product-specific standards is intended to guide the cosmetics industry in adopting the “One Product, One Standard” approach.
1. Scope of Application
Includes testing items, specifications, quality management measures, and brief descriptions.
2. General Principles
Quality control measures should be practical, compatible with manufacturing processes, and capable of ensuring the stability and consistency of product quality.
3. Main Content
The research on quality control standards for hair dye cosmetics primarily covers product stability, quality control items and specifications, and quality management measures.
(1) Stability Study
Indicators that affect product quality, safety, and efficacy—such as product appearance and the content of active ingredients—should be selected as evaluation parameters. The influence of factors such as temperature, humidity, and light on these indicators should be assessed. Furthermore, the impact of packaging materials on product quality should also be taken into consideration.
(2) Research on Quality Control Items and Specifications
The quality control items and specifications shall be no less comprehensive than those outlined in the Inspection Specifications, and should include indicators for hazardous substances, microorganisms, and active ingredients (hair dyes).
For products involving two or more components mixed for use, quality control items and specifications should be determined separately based on each formulation.
Physicochemical Items and Specifications:
- Hazardous Substances: Mercury, lead, arsenic, cadmium, etc., must comply with the Technical Specifications. For formulations containing ethoxylated structures, dioxane must be included as a control item. When the combined content of ethanol and isopropanol is ≥10% (w/w), methanol must be included as a control item.
- Active Ingredients (Hair Dyes): The upper limit of content must comply with the Technical Specifications. If the content exceeds the reasonable control range, sufficient justification must be provided to demonstrate the stability of the manufacturing process and the controllability of product quality. For two-component mixtures, the expression of control ranges for hair dye indicators must be standardized (e.g., expressions like “2±20%” or “2%±20%” are not acceptable). Pay attention to the conversion between “Toluene-2,5-diamine sulfate” and “Toluene-2,5-diamine”.
- Other Items: If the formulation contains thioglycolic acid or its salts, the product standard should include control of items such as pH and oxidant content.
Microbiological Items and Specifications:
- For oxidative hair dye products, microbiological control is not required.
- For non-oxidative products, microbiological control must be implemented.
(3) Research on Quality Management Measures
There should be a clear correspondence between the "Quality Management Measures" and the "Brief Description" for each item and specification.
Testing Methods:
In principle, methods specified in the Technical Specifications should be used. The specific name of the testing method must be clearly indicated (e.g., “Test according to Chapter 4, Section 7.2 of the Technical Specifications for 32 components including p-phenylenediamine”).
For methods not included in the Technical Specifications, validation should be conducted against the specified methods in the Technical Specifications. For items not yet covered by testing methods in the Technical Specifications, methodological validation should be performed for the methods used.
Non-Testing Methods:
When hair dyes are used as active ingredients, relying solely on “control of raw material-related indicators” is insufficient to ensure compliance with hair dye specifications. Quality management measures may include “control of manufacturing process flow” or a combination of non-testing and testing methods, such as “control of manufacturing process flow + testing method” or “raw material indicator control + testing method.”
For hair dyes without established testing methods, control through manufacturing process flow may be adopted.
When the content of a hair dye is below the quantification limit of the testing method, a combination of testing and manufacturing process control may be used.
4. Other Requirements
Product quality control studies should take into account sensory indicators (such as color, appearance, odor), storage conditions, and shelf life.
About CIRS
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