Soy Isoflavones Quality and Labeling Standard
JHFC-S-049 Enacted: 8 September 2026 / Effective: the same day
Japan Certified Health Food Council (JHFC) — English translation of the standard. In case of discrepancy the Japanese text prevails. Japanese original
Japan Certified Health Food Council (JHFC)
Enacted: 8 September 2026 / Effective: the same day
Preamble (Rationale for Enactment)
Certificates of analysis for soy isoflavones contain values measured as glycosides, aglycone values, and converted totals. Composition also changes in raw materials subjected to heating or enzyme treatment, and even identically described totals may not cover the same constituents. This Standard is established to link the forms measured with the labeling basis and to prevent errors in transcribing raw material weight as constituent amount.
Article 1 (Purpose)
This Standard provides for verification of quantification by form, conversion, and ingredient descriptions for soy-derived isoflavones using consistent documentation. JHFC-A-001 shall serve as the standard for information disclosure, and this document specifies additional requirements for handling quantities of glycosides and aglycones.
Article 2 (Scope)
Products Covered
This Standard applies to isoflavone-containing raw materials obtained from soybeans, soybean germ, and similar sources, and to tablets, capsules, powders, beverages, and similar products declaring their amounts. It includes materials with a history of extraction, fermentation, or enzyme treatment. Isoflavones derived from plants other than soybeans and equol shall not be added to the totals under this document.
Article 3 (Terms and Definitions)
- 1. Aglycones: In this document, the forms of daidzein, genistein, and glycitein without attached sugars.
- 2. Glycoside groups: Groups of constituents distinguished as glycosides of the above aglycones and their acetylated and malonylated forms.
- 3. Aglycone equivalent amount: The amount obtained by converting the measured amount of each form into the mass of the corresponding aglycone and summing the amounts with the included constituents specified.
- 4. Conversion during sample preparation: A change in the form measured due to hydrolysis or similar processes during preparation of an analytical sample.
Article 4 (Requirements)
1. Quality Requirements—Soy Origin and Composition by Form
The soybean parts used and the separation process shall be verified through receipt documentation, and analytical profiles of raw materials shall be compared with reference materials. The relationship between aglycones and glycoside groups shall be made verifiable by reference to the [composition explanation in official assessment documentation](https://www.mhlw.go.jp/shingi/2006/05/dl/s0531-8c01.pdf). The business operator shall establish specifications for content by form, residual solvents, and foreign matter, and shall present supporting evidence based on the parts used and the production method.
2. Quality Requirements—Process Control Involving Sugar Removal
Where glycoside composition is changed through fermentation or enzyme treatment, results by form before and after treatment and records of reaction completion shall be compiled. The operations performed for enzyme or microbial cell removal, inactivation, concentration, and drying shall be verified. When different lots are blended to adjust composition, the composition by form as well as the total amount shall be calculated and reconciled with input records and post-blending analysis.
3. Testing—Direct Quantification and Quantification after Hydrolysis
The request to the third-party institution shall specify whether the method measures each form directly or measures aglycones after hydrolysis. Conversion during extraction, completion of hydrolysis, and loss of analytes shall be investigated by recovery testing. Aglycones originally present and values obtained after hydrolysis shall not be counted twice in the sum. The institution name, method, sample stage, relevant lot, and contact point for inquiries shall be disclosed.
4. Labeling Requirements—Conversion Tables and Daily Amounts
The soy isoflavone amount per recommended daily intake shall be stated with an indication that it is expressed as aglycone equivalents. Where the measured weight of glycosides is also provided, it shall be labeled as a separate value. The correspondence between molecular weights, purity corrections for reference materials, and the constituents included in the sum shall be recorded in a calculation sheet. Proofreading shall verify that the formulation amount of the extracted raw material, the raw material specifications, and the values in the product have not been confused.
5. Quality Requirements—Coexisting Soy Constituents
The residual presence of soy proteins, lipids, and sugars shall be examined through raw material documentation and reflected in the assessment of effects on analytical extraction and in ingredient descriptions. The business operator shall select test items such as pesticide residues and microorganisms and shall present assessment specifications in accordance with the purification route. Cautionary statements concerning soy origin shall not be omitted solely because the material is an extract; their inclusion or omission shall be verified against the product formulation and supply documentation.
6. Quality Requirements—Tracking Individual Forms during Storage
Moisture absorption shall be recorded for powders, and liquid properties and heating conditions shall be recorded for beverages. The total equivalent amount and composition by form shall be verified after storage. For formulations exhibiting precipitation or adhesion to the container, sample preparation capable of recovering the entire amount shall be verified. The business operator shall establish specifications for storage duration, content variation, and appearance, and shall label storage methods and handling after opening in accordance with the supporting evidence.
7. Precautions for Intake
Routine consumption of soy foods shall be distinguished from additional use of concentrated raw materials, and guidance shall advise caution regarding concurrent use of other isoflavone-containing products. Official cautionary information concerning pregnancy, breastfeeding, and children shall be reflected in labeling of intended users, and the documentation adopted shall be retained. Packaging proofreading shall verify the inclusion of a statement advising persons undergoing treatment or taking medication to consult a physician and of a soy allergy cautionary statement.
8. Documentation Management
Certification of reference materials for each form, the rationale for selecting direct quantification or quantification after hydrolysis, conversion tables, and original analytical profiles shall be retained together. The business operator shall establish the retention period, and when calculation methods are updated, a version allowing previous label values to be reproduced shall be retained. If a conversion error is identified, the affected manufacturing lots and public disclosure media shall be identified, and a correction history shall be retained.
Article 5 (Evaluation Categories)
- Conformity: All requirements are satisfied, and calculations can be reproduced from measurement of each form through conversion to the daily amount.
- Partial conformity: Origin, conversion, and cautionary statements have been verified, and deficiencies limited to guidance on accessing documentation are remedied within a specified deadline.
- Nonconformity: Glycoside weight is incorrectly labeled as the equivalent amount, values before and after hydrolysis are counted twice, or soy origin cannot be verified.
Article 6 (Implementation)
The business operator shall prepare a self-declaration of conformity using a list of the constituents included in the conversion. The Council shall focus its verification on analytical sample preparation and labeling calculations for the product covered by the application. Reevaluation shall be performed when enzyme treatment, composition by form, or conversion formulas change, and periodic review shall be conducted together with a review of official cautionary information.
Supplementary Provisions
This Standard shall apply from 8 September 2026. Inquiries concerning equivalent amounts shall include the category of sample preparation used before measurement.
※ This Standard sets out evaluation criteria for information disclosure and quality management practices and does not guarantee the effects, efficacy, or safety of individual products.