AI Utilized to Evaluate Skin Sensitization Risk

Hoyu Co., Ltd. (Head Office: Nagoya City, Aichi Prefecture, President & CEO: Yoshihiro Sasaki, hereinafter referred to as Hoyu) is pleased to announce that the results of its joint research with the National Institute of Health Sciences (Location: Kawasaki City, Kanagawa Prefecture, Director: Yoshitaka Saito) and Nagoya City University (Headquarters: Nagoya City, Aichi Prefecture, President: Kenjiro Kori) have been recognized with the Excellent Paper Award at the 51st Annual Meeting of the Japanese Society of Cosmetic Chemists (June 24-25, 2026).

Research Background and Results

This research aimed to achieve a quantitative risk assessment that does not rely on animal testing, by utilizing AI (machine learning) for the evaluation of skin sensitization (the property of causing skin allergies) of chemical substances, an evaluation that has traditionally depended on animal testing.

In the safety evaluation of cosmetics, establishing methods to evaluate skin sensitization without relying on animal testing is a challenge. In recent years, in addition to growing concern for animal welfare and animal protection, regulations on animal testing in the cosmetics field are progressing globally. Therefore, there is a demand for the establishment of new evaluation methods that ensure safety without relying on animal testing.

In this research, we developed an evaluation approach that predicts the strength of skin sensitization from information about chemical substances using machine learning. Furthermore, through a case study targeting bandrowski's base, which can be generated in hair color formulations, we demonstrated the potential for quantitative risk assessment that does not rely on animal testing.

Key Points of This Research

- Proposes a quantitative evaluation approach for skin sensitization using machine learning

- Presents an example of Next Generation Risk Assessment (NGRA) that leads to safety evaluation independent of animal testing

- Verifies the potential for practical application using hair color-related substances as targets

Goals of This Research

Some ingredients used in cosmetics and hair colors have excellent functions but are difficult to utilize from a safety perspective.

If skin sensitization risk can be quantitatively estimated using this technology, it may lead to product development that utilizes useful ingredients more safely by devising formulation amounts and design.

Furthermore, this research is expected to contribute to the advancement of new safety evaluation methods that do not rely on animal testing.

Future Initiatives

Hoyu will continue to develop advanced safety evaluation technologies and strive to create products that can be used with greater safety and peace of mind.

Award-Winning Paper

Paper Title

Next Generation Risk Assessment Case Study: A Skin Sensitization Quantitative Risk Assessment for Bandrowski’s Base Existing in Hair Color Formulations

(Japanese Translation: Next Generation Risk Assessment Case Study: Quantitative Skin Sensitization Risk Assessment for Bandrowski’s Base in Hair Color Formulations)

Journal of the Japanese Society of Cosmetic Chemists Vol. 48, No. 2, pp. 73–77 (2024)

Authors

Takao Ashikaga1, Kota Hatano2, Honoka Iwasa2, Kei Kinoshita3, Nobuaki Nakamura2, Kaori Abe3, Masahiro Atamakin3

1 Department of Genomic Safety Science, National Institute of Health Sciences

2 Hoyu Co., Ltd.

3 Graduate School of Pharmaceutical Sciences, Nagoya City University

Collaborative Research Structure

This research was conducted under industry-academia-government collaboration among the National Institute of Health Sciences, Hoyu, and Nagoya City University. The lead author, Takao Ashikaga, is engaged in research in the field of safety science at the National Institute of Health Sciences and is also in charge of the operation of the Japan Center for the Validation of Alternative and Complementary Methods (JaCVAM). Additionally, co-author Kaori Abe is engaged in research in the field of regulatory science at Nagoya City University and is currently affiliated with the Graduate School of Data Science at Nagoya City University.

About the Japanese Society of Cosmetic Chemists

The Japanese Society of Cosmetic Chemists was established in 1976 and is a society where dermatologists, cosmetic researchers, pharmaceutical researchers, and others discuss medical and scientific issues related to cosmetics, fragrances (cosmetics), and their related substances.

The Excellent Paper Award is presented every two years to research that is judged to have made a particularly significant contribution to the advancement of cosmetic science, selected from papers published in the Journal of the Japanese Society of Cosmetic Chemists.

About IKIWAKI WAKUWAKU VISION 2030

Hoyu has set forth "IKI WAKU WAKU VISION 2030" and aims to realize a sustainable society by creating value in three aspects: customers, environment, and employees. Based on the corporate slogan "COLOR YOUR HEART," this vision consists of the "Customer Coloring Vision" that brings color to customers' lives, the "Environment Coloring Vision" that promotes reduction of environmental impact and 4R, and the "Employee Coloring Vision" that creates an environment where employees feel healthy and fulfilled both physically and mentally.

About Hoyu Co., Ltd.

Since its founding in 1905 (Meiji 38), Hoyu has been engaged in the business of hair color and hair care cosmetics for home use and professionals. It boasts the No. 1 domestic market share*1 in the retail hair color market and has been involved in the manufacturing, sales, research, and development of hair color-related products for many years.

Celebrating its 100th anniversary in 2023, the company continues to move towards the next 100 years with its unwavering commitment to creating new things, including aggressive overseas business expansion and challenges in the allergy field with a forward-looking approach to safety research.

*1 Survey Period:

Intage SRI Hair Color Market: Cumulative sales amount for each year from January 1996 to December 2017 Intage SRI+ Hair Color Market: Cumulative sales amount for each year from January 2018 to December 2025

Hoyu Co., Ltd. Company Overview

Head Office: 1-501 Tokugawa, Higashi-ku, Nagoya City, Aichi Prefecture

Representative: Yoshihiro Sasaki, President & CEO

Founded: 1905 (Meiji 38)

Established: 1923 (Taisho 12)

Capital: 110 million yen

Number of Employees: 1,036 (as of October 31, 2025)

Consolidated Net Sales: 52.7 billion yen (Fiscal year ending October 31, 2025)

Domestic Production Sites: Seto Factory (106-2 Yamano-da, Seto City, Aichi Prefecture), Sakuragaoka Factory (985 Anada-cho, Seto City, Aichi Prefecture)

Business Activities: Manufacturing and sales of hair color and hair care cosmetics

HP Address: https://www.hoyu.co.jp/

About the National Institute of Health Sciences

The National Institute of Health Sciences is a national research institution that conducts research on ensuring the safety of pharmaceuticals, foods, chemical substances, etc., and promotes research in the field of safety science, including toxicity evaluation and test method development.

About Nagoya City University

Nagoya City University conducts education and research in a wide range of fields, including medicine, pharmacy, and data science, and promotes diverse research, including the safety evaluation of pharmaceuticals and chemical substances.