Japan does not (yet) have a dedicated legal category or standalone registration regime for plant biostimulants (as exists in the EU under the Fertilising Products Regulation or various national legislations). As a result, biostimulants are currently not defined as a separate product category in Japanese law.

To market your biostimulant on the Japanese market, you will have to first identify in which existing legislative framework your product fits, namely:

- Fertilizer / plant nutrient

- Soil conditioner

- Other agricultural production material

- Agrochemical (PPP)

The definition of fertilizer is clearly stated in Article 2 of the Act on Assurance of Fertilizer Quality ([https://laws.e-gov.go.jp/law/325AC0000000127]): (1) To provide nutrients to plants; (2) A substance applied to land with the purpose of bringing about chemical changes in the soil to contribute to plant cultivation; and (3) A substance applied to plants with the purpose of providing nutrients to plants. There are two types of fertilizers: "special fertilizers" and "ordinary fertilizers." Special fertilizers are those made from rice bran, compost, etc., while ordinary fertilizers are anything other than that.

The Fertiliser control law (肥料の品質の確保等に関する法律) covers the definition of fertilizers, quality standards, permitted ingredients and labeling requirements. In case your product fits under these categories of products, you will have to comply with these provisions (source: [https://biostimulant.jp]).

Should your biostimulant claims plant growth regulation, pest control, disease suppression, or similar effects, Japanese authorities may interpret it as an agricultural chemical (pesticide) subject to the registration under the Agricultural Chemicals Regulation Law (Plant protection products, out of scope of biostimulants and fertilisers).

With biostimulants being more and more present on the Japanese market, a Japanese Biostimulant Council was founded and a voluntary non-binding but highly recommended guidelines on labelling of Biostimulants was issued in May 2025: In May 2025, the Ministry of Agriculture, Forestry and Fisheries (MAFF) released a non-binding guideline titled:

バイオスティミュラントの表示等に係るガイドライン

(Guideline on Labeling etc. for Biostimulants), which can be found here: [https://www.maff.go.jp/j/jas/jas\_kikaku/attach/pdf/tokusai\_a-5].pdf)

Because there's no formal registration requirement, the Japan Biostimulant Association (日本バイオスティミュラント協議会)([https://www.japanbsa.com/index.html]) has developed voluntary standards that many producers follow. It is not a law, but is increasingly used by industry and government as a reference for compliance. These self-regulating rules include product classification, safety information disclosure, avoiding pesticide-like claims and quality standards and documentation.

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The sciBASICS Team.