No, the ingredient is not automatically prohibited. Japan's regulatory system operates on a principle of entrepreneurial responsibility. This means that while the government provides positive and negative lists for common ingredients, companies are ultimately responsible for ensuring the safety and compliance of their products. Unlisted ingredients may be used in cosmetics at the company’s discretion, provided their use is safe and compliant with applicable regulations.

Quasi drugs are a product category unique to Japan, which falls in between pharmaceuticals and cosmetics. They contain active ingredients approved by the Ministry of Health, Labour and Welfare (MHLW) and have stronger efficacy. Common examples include deodorants, depilatories, hair dyes, hair perms, products promoting hair growth, and medicated cosmetics (whitening, anti-acne, anti-aging products, etc.).

Japan mainly adopts the following 10 lists to regulate the application scope and use limitations of quasi-drug ingredients:

1) List of Additives for Quasi-drugs

2) List of Additives for Hair Dyes

3) List of Additives for Permanent Wave Products

4) Standards for Marketing Approval of Hair Coloring Agents

5) Standards for Marketing Approval of Permanent Wave Agents

6) Standards for Marketing Approval of Medicated Oral-care Products

7) Standards for Marketing Approval of Bath Additives

8) List of Active Ingredients for Medicated Cosmetics

9) Instructions for Application of Marketing Approval for Medicated Soaps

10) Instructions for Application of Marketing Approval for Medicated Shampoo and Hair Conditioner

In the Cosmetic Ingredient Search Tool, the data in the first three lists above has been integrated into the “List of Permitted Additives for Quasi Drugs”, and the data in the last seven lists has been integrated into the “List of Permitted Active Ingredients for Quasi Drugs.”

The most significant difference between quasi-drugs and cosmetics is whether they contain “active ingredients” that claim specific efficacies. If the products do not contain an active ingredient, it will be considered cosmetics. In terms of effectiveness, it will be relatively mild than quasi-drugs. 

Only products containing active ingredients approved by MHLW can be marketed as quasi-drugs in Japan. For such products, their efficacy claims shall be consistent with the efficacy of the active ingredients used. For example, a product can claim whitening efficacy if it contains a whitening active ingredient. A product can claim anti-acne efficacy if it contains an anti-acne active ingredient.

Quasi-drug active ingredients are defined as “ingredients that have specific efficacies and are approved under the Pharmaceuticals and Medical Devices Act”. The concentration, quality and safety, approval systems of active ingredients are subject to strict regulations and reviews.

The additives refer to ingredients other than the active ingredients in quasi-drugs, such as excipients, stabilizers, emulsifiers, buffer agents, adhesives, colorants, fragrances, corrective agents, etc.

Yes, but they need to apply to MHLW for new ingredient registration and get approval. It is noteworthy that MHLW implements a strict approval system for new ingredients. For details about New Quasi-drug Ingredient Application, please refer to Cosmepedia: Japan Quasi-drug Regulation.