Microneedle technology integrated with diverse therapeutic modalities for hair regrowth in alopecia

Alopecia profoundly impacts an individual's appearance, quality of life, and social well-being, with its prevalence increasing with age. Conventional treatments, such as topical minoxidil and oral finasteride, suffer from limitations like inefficient drug delivery, side effects, and inconsistent efficacy. Other therapies, like hair transplantation, biologics and low-level laser therapy (LLLT), also face some constraints in practical application. Microneedles (MNs), as an emerging transdermal drug delivery system (TDDS), enable efficient local delivery of therapeutic agents to hair follicles in the balding scalp by physically penetrate stratum corneum. Through enhanced drug permeability and activation of follicular regeneration pathways, MN-combined strategies have ignited considerable research interest. This review outlines the advances in MN-mediated alopecia treatments over the past five years and underscores their potential to enhance hair regrowth efficacy, including MN-assisted delivery of chemical drugs, natural compounds, biologics, nanomedicines, stem cells, and LLLT. Additionally, this review also summarizes the advances in clinical trials of MN-combined therapies for alopecia over the past five years, highlighting the noticeable disconnection in research focus between basic research and clinical trials. In summary, this review aims to provide critical insights and future perspectives for the development of MN-integrated therapies for alopecia management.