Rohto's Original Milk Peptide Found to Act on Growing Muscles, Not Just Bones and Blood

Rohto Pharmaceutical Co., Ltd. (Headquarters: Osaka City, President: Hidetoshi Segi) is advancing research on its proprietary ingredient Oligomil® (milk-derived hydrolyzed peptide, hereinafter referred to as milk peptide) towards the realization of the Rohto Group Integrated Management Vision 2030, 'Connect for Well-being & Longevity.' In a joint research project with National University Corporation Mie University (Location: Tsu City, Mie Prefecture, President: Masaaki Ito) (Principal Investigator: Professor Norihiro Nishimura, Graduate School of Regional Innovation Studies; Research Lead: Lecturer Yasuhito Shimada, Graduate School of Medicine / Zebrafish Research Center, et al.), the company has revealed the potential of milk peptide to act on muscles, in addition to bones and blood. These research results were presented as a poster at the 99th Annual Meeting of the Japanese Pharmacological Society. We will continue to accumulate research results that can support the growth of children who will lead the future. ◆ Key Research Findings - Focusing on bones, blood, and muscles, which form the foundation of physical development during the growth period, we have previously confirmed that Oligomil (milk peptide) promotes bone formation and increases red blood cells. This time, we have newly confirmed its effect on muscles (motor performance). - Oligomil (milk peptide) was suggested to enhance the expression of genes related to fast-twitch muscles, which are involved in explosive movements and rapid exercise, indicating an effect on muscles responsible for quick power. - These research results are expected to be utilized in future product development as material research supporting healthy physical development during the growth period. Research Background Oligomil was developed as a raw material in 2009 and has been found to have immunostimulatory and anti-allergic effects. Oligomil contains numerous peptides (chains of 2 to 50 amino acids), and since peptides have the function of regulating living organisms, we believe it holds significant potential for health maintenance. Focusing on the growth period, which is key to supporting healthy physical development, we have previously clarified through joint research that it promotes bone growth and increases red blood cells. This time, we investigated its effects on muscles during the growth period and, furthermore, on motor performance. Results Oligomil was administered to juvenile zebrafish, a model of the growth period, and their swimming ability was observed after 8 days. Compared to the control group that did not receive Oligomil, the Oligomil-administered group showed an increase in the speed of explosive movements (maximum swimming speed) (Figure 1). Furthermore, gene expression analysis in skeletal muscle revealed increased expression of gene groups involved in promoting skeletal muscle formation and gene groups related to fast-twitch muscles, which are responsible for explosive power (Figure 2). Figure 1: Effect on Maximum Swimming Speed (Critical Swimming Speed) Three-month-old zebrafish were fed feed containing Oligomil twice a day. After 8 days, the critical swimming speed (Ucrit) was measured. Student's t-test was used for comparison between the two groups. Compared to the control feed group without Oligomil, the Oligomil-containing feed group showed a significant (p<0.05) increase in critical swimming speed, suggesting the promotion of explosive motor performance. Data are presented as mean ± standard deviation. (Conducted by Mie University) *Critical swimming speed refers to the maximum speed at which a fish can no longer swim against a gradually increasing water current, and is a standard indicator of endurance swimming ability and overall motor performance. Figure 2: Evaluation Results of Gene Expression Analysis in Skeletal Muscle Three-month-old zebrafish were fed feed containing Oligomil twice a day. After 14 days, skeletal muscle was collected and gene expression analysis was performed. Student's t-test was used for comparison between the two groups. Compared to the control feed group without Oligomil, the Oligomil-containing feed group showed a promoting effect on the increased expression of myosin, a protein involved in muscle contraction, and significant promotion of gene expression for pax3a (a transcription factor for muscle differentiation), myod (a master gene inducing differentiation into muscle cells, a myogenic regulatory factor), and srf (serum response factor), which are related to the induction of myoblast differentiation (p<0.05). Furthermore, it was revealed that the expression levels of tnnt3b and tnni2a, which are related to fast-twitch muscles, were significantly increased. Data are presented as mean ± standard error. (Conducted by Mie University) Impact of This Research on Society (Significance of This Research) This study demonstrated that milk peptide acts on muscles from multiple aspects, including motor performance, muscle structure, and the molecular mechanisms involved in muscle formation. In addition to the previously clarified effects on bones and blood, this suggests the potential of this ingredient to be broadly involved in functions important for physical development. (Reference Material) ・Rohto's original milk peptide discovered to promote bone growth and increase red blood cells during the growth period! https://www.rohto.co.jp/research/researchnews/technologyrelease/2023/1222_01 Background of This Study This research is one of the outcomes of a joint research agreement signed between Mie University and Rohto Pharmaceutical in 2018. Special Notes These research results were presented as a poster at the 99th Annual Meeting of the Japanese Pharmacological Society. Conference Name: 99th Annual Meeting of the Japanese Pharmacological Society (March 16-18, 2026) Title: "Body-building promoting effects of milk-derived hydrolyzed peptides (HMPs) ~ New developments in skeletal muscle following effects on bone and blood" Misa Nakai1, 2, Jotaro Inaba3, Liqing Zang1, 2, Kazutake Fukada2, 4, Norihiro Nishimura1, 2, Yasuhito Shimada2, 3 1) Graduate School of Regional Innovation Studies, Mie University, 2) Zebrafish Research Center, Mie University, 3) Department of Integrative Pharmacology, Graduate School of Medicine, Mie University, 4) Rohto Pharmaceutical Co., Ltd.