Discovery: Minoxidil Forms Vascular Networks and Improves Hormone-Induced Dermal Papilla Miniaturization

Taisho Pharmaceutical Co., Ltd. [Headquarters: Toshima-ku, Tokyo; President: Shigeru Uehara] (hereinafter "the company") has discovered through joint research with Professor Ken-ichi Mizutani of the Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, that the hair growth ingredient minoxidil may enhance blood circulation by increasing vascular density around the dermal papilla and reconstructing vascular networks. Furthermore, it may improve dermal papilla miniaturization caused by male hormones, thereby contributing to improved hair growth environments and healthy hair development in androgenetic alopecia (AGA). These findings have been published in the international academic journal Scientific Reports, issued by Springer Nature.

◇ Research Background

Minoxidil is an approved active ingredient used in hair loss treatment due to its recognized hair growth effects on androgenetic alopecia (AGA), also known as male pattern baldness, and is widely used both domestically and internationally. As a pioneer in minoxidil research in Japan, the company has conducted extensive research for over 40 years, spanning from basic to applied studies.

As part of these efforts, the company has collaborated with Professor Ken-ichi Mizutani of the Graduate School of Pharmaceutical Sciences, Kobe Gakuin University, to elucidate new mechanisms of action of minoxidil※1.

In this study, we focused on the "dermal papilla," known to act as the command center regulating hair growth and involved in determining hair thickness※2. We investigated how minoxidil affects the dermal papilla and surrounding blood vessels, yielding the following research results.

◇ Research Findings

①: Minoxidil increases vascular density around the dermal papilla

②: Minoxidil suppresses male hormone-induced dermal papilla miniaturization

③: Minoxidil inhibits male hormone-induced suppression of vascular network formation

【Research Finding ①】

Minoxidil increases vascular density around the dermal papilla

Blood vessels are vital organs that supply nutrients and oxygen to all tissues and cells and play an extremely important role in hair follicle growth. When minoxidil was applied to genetically modified mice capable of visualizing blood vessels, analysis of skin tissue revealed increased blood vessels around hair follicles compared to untreated mice, with a particularly notable increase in capillary density surrounding the dermal papilla (Figure 1). These results suggest that minoxidil selectively enhances blood vessel formation near the dermal papilla, creating an environment where the dermal papilla can more easily receive oxygen and nutrients, thereby supporting hair growth.

Figure 1: Increased vascular density around the dermal papilla (DP) following minoxidil application

【Research Finding ②】

Minoxidil suppresses male hormone-induced dermal papilla miniaturization

In AGA, it is known that male hormones cause "follicular miniaturization," resulting in only thin, short hairs growing. Since male hormones are believed to inhibit dermal papilla cell proliferation, contributing to shortened hair cycles and hair loss, we examined the effects of male hormones on the dermal papilla and the impact of minoxidil.

When male hormones were applied to mice, the dermal papilla became miniaturized. In contrast, when minoxidil was applied, male hormone-induced dermal papilla miniaturization was suppressed (Figure 2). These results suggest that minoxidil improves dermal papilla miniaturization caused by male hormones and may contribute to healthy hair growth.

Figure 2: Inhibitory effect of minoxidil on male hormone-induced miniaturization of the dermal papilla (DP)

【Research Finding ③】

Minoxidil inhibits male hormone-induced suppression of vascular network formation

Furthermore, to clarify the effects of male hormones on blood vessels surrounding the dermal papilla, cultured human vascular cells were used. When human vascular cells were cultured on a special gel, they formed vascular networks. However, treatment with male hormones reduced vessel length and branching, inhibiting vascular network formation. In contrast, treatment with minoxidil increased vessel length and branching, suppressing the male hormone-induced inhibition of vascular network formation (Figure 3). These results suggest that minoxidil improves functional impairment of vascular cells caused by male hormones, increases vascular density, and reconstructs vascular networks, thereby potentially suppressing dermal papilla miniaturization.

Figure 3: Inhibitory effect of minoxidil on male hormone-induced suppression of vascular network formation

◇ Summary

From the above three research findings, it was demonstrated that minoxidil may improve the hair growth environment in AGA and support healthy hair development by increasing vascular density around the dermal papilla, reconstructing vascular networks to regulate blood flow, and improving male hormone-induced dermal papilla miniaturization. Further research is expected to provide deeper insights into the mechanisms of action of minoxidil.

To address various hair-related issues, the company will continue its research activities in hair science under the motto of "Taisho Pharmaceutical's Hair Care Research: Scientifically Enabling Hair Growth," contributing to a richer life for consumers.

※

Ying Zeng, Akinari Abe, Satsuki Takashima, Miyu Kono, Reina Kagiyama, Mariko Komabayashi-Suzuki, Mariko Moriyama, Hiroyuki Moriyama, Tadashi Okamoto, Hideya Ando, Masaki Tanaka, Masamitsu Ichihashi, Masatsugu Ema, and Ken-ichi Mizutani, “Preferential Crosstalk between Perifollicular Capillary Vessels and Dermal Papilla Cells during Hair Cycling Homeostasis.”, Scientific Reports, 16:15328, 2026.

DOI: https://doi.org/10.1038/s41598-026-46001-2

【Supplementary Information】

※1

Released on September 1, 2023

Discovery of a New Mechanism of Action for the Hair Growth Ingredient Minoxidil ~Increased Capillary Formation Around Hair Follicles~

URL: https://www.taisho.co.jp/company/news/2023/20230901001380/

※2

Elliott K., et al., J. Invest. Dermatol., 113(6):873-7, 1999.

※3

Bg (Bulge region): The upper region of the hair follicle where hair follicle stem cells, the origin of hair, accumulate.

※4

VEGFR1: A receptor that transmits signals of vascular endothelial growth factor (VEGF), which plays an important role in capillary formation, into the cell. It is primarily present in vascular cells.

※5

HG (Hair germ): Tissue containing cells that generate new hair.

※6

K15 (keratin 15): A representative marker of hair follicle stem cells present in the bulge region of the hair follicle.